[Newbie Needs Direction]

The ozonator (if working properly) should shock your pool water so you will not need to use non-chlorine shock. So in that case, lowering the TA is the way to go for sure. Keep in mind that the use of an ozonator will breakdown some of the chlorine as well so even with more Dichlor you may still see significant chlorine usage. That's just part of the price of using an ozonator with chlorine. It doesn't have this problem with bromine and can reactivate bromide (but can produce some bromate by-products).

The standard Taylor K-2006 only measures down to 30 ppm, but it's somewhat easy to see that the black dot is going to disappear somewhere beyond 30 ppm. Besides 30 ppm isn't horrible. Taylor does sell a separate test kit just for CYA that measures to 20, but that's more expensive. Yes, you add the Dichlor in increments over time -- just add what you need for raising FC and realize that you add to CYA by almost the same amount.

You should get the Taylor K-2006 test kit since that will test everything you need including Free and Combined chlorine separately (the chlorine test is called FAS-DPD and is drop-based where you count the drops and multiply by 0.2 or 0.5 depending on the sample size). Yes, Free Chlorine doesn't smell (or smells very faintly like the "clean" smell of bleach) and is the active form of chlorine (though some of it is bound to CYA and is in "reserve" and not on the "front lines" so to speak) while Combined Chlorine is chlorine that is attached to organics or ammonia and is no longer active and may smell (chlorine attached to ammonia is called chloramine and smells bad).

For bringing down the TA it's the following sequence of steps:

1) Add acid to lower pH to 7.0

2) Aerate (run spa jets) and monitor the pH. When it gets to 7.2, add acid to lower the pH back to 7.0 and repeat this process and periodically measure the TA. It should be dropping. When the TA gets to where you want it (say 60), go to the next step.

3) When you reach your target TA level continue to aerate, but don't add any more acid. This will cause the pH to rise with no change in TA.

The reason this works is that aerating raises the pH with no change in TA while acid lowers both pH and TA so the combination just lowers the TA.

If you don't understand something, it's my fault, not yours. I'm the one who needs to be patient so don't be afraid to ask questions.

[Newbie Needs Direction]

I suggest just using Dichlor until you get your CYA to around 20 ppm or so. This is around 2.25 ounces weight of Dichlor. My guess is that this is somewhere around 1-2 fluid ounces so that's 6-12 teaspoons total (cumulative). Then you can switch back to your bleach. 5 fluid ounces of Ultra bleach, if it's 6% bleach, (Ultra store brand is usually 6%; Clorox Ultra may be 7-8%; Clorox Regular is 6% -- see what your bottle says on it, if it does) should result in 5.7 ppm FC so that's how much you seem to be using which is high, but that's partly because you don't have enough CYA yet to keep the chlorine from outgassing so much. This should get a little better over time, though I still expect you to use a lot of chlorine if you use the hot tub as much as you indicate -- that's no problem, just add it after you get out. It might be interesting for you to see how much chlorine is lost in between when you get out, turn off the jets, and add chlorine until the next time you take off the cover and measure chlorine again (before you turn on the jets and get in). I suspect most of the loss is during your time in the spa, but this can verify that.

You do not need to use spa shock. Instead, you should buy non-chlorine shock, potassium monopersultate, and use that weekly (scale down the amount for your spa -- it might only list pool quantities).

You won't need to check on the CYA level again once you've added your Dichlor and gotten it to around 20 ppm (your test kit might only test down to 30 ppm anyway, so it's somewhat of an estimate based on adding 20 ppm FC worth of Dichlor cumulatively). You could check it after a month just to see that it's still there, but it should be (if not, add more Dichlor).

NOTE: The non-chlorine shock will be acidic so it's weekly use will likely take care of at least part of the pH problem, but read below for a procedure to lower the TA, BUT first get to using the non-chlorine shock since that will help somewhat. Though I describe lowering the TA to 50, you should probably lower it to 60 first and see how that is for you. If you go too low, then the non-chlorine shock you add might make the pH go lower than you want.

As for the pH rise, you can lower your TA level quite a bit. Ironically, the easiest way to do that is to run your jets (i.e. to aerate), but do so at low pH (7.0). It will take 1.5 ounces weight (about 0.6 fluid ounces or 3-4 teaspoons) of dry acid (sodium bisulfate) to lower your pH to 7.0 and then you'll need to run the jets (which will make the pH rise) and add acid to keep the pH at 7.0 and continue this until you get your TA to 50 ppm. It will take about 4.4 ounces weight (about 1.7 fluid ounces or 10 teaspoons) of acid cumulatively (not all at once, of course). Once your TA is at 50, stop adding acid but continue to aerate. The pH will then rise so stop aerating when the pH gets to 7.5 and could actually use 7.7 as a target pH since the pH rise should be less at that pH (especially with the lower TA).

At this lower TA, you should have a lot less outgassing of carbon dioxide and a lot less of a pH rise. I am assuming that you have no exposed tile with grout or anything like that -- the lower TA will be corrosive to plaster/gunite/grout unless the pH and CH are kept up. Most hot tubs don't have that, but I thought I'd ask to be sure. Over time, you can monitor your TA and increase it since it may go down some over time (or might not -- you'll have to see).

Be sure and let us know your progress and if this works for your pH rising problem.

[I Got My Test Kit....now Some Questions]

You can get Calcium Chloride from a pool store -- it's the product used to increase Calcium Hardness. But you don't want to add too much. You don't need to go above 200 ppm with that and don't want to go much above 300 ppm or else you could get cloudiness and scaling. As for adding regular salt (sodium chloride), you can get that as either "pool salt" from the pool store (used with saltwater chlorine generator pools) or "water softener" salt probably sold at hardware stores. Just make sure whatever salt you use is very pure (the two I mentioned are). You will probably notice a nice feel of the water at 1000 ppm for regular salt. Basically, this is similar in concept to adding bath salts to your bath. It's completely optional.

To raise your Borate level to 50 ppm using Borax, it takes 4.5 ounces weight per 100 gallons which is around 2.4 fluid ounces per 100 gallons. Borax is basic/alkaline, so it will take 3.8 ounces weight per 100 gallons of dry acid (sodium bisulfate) which is 1.5-3 fluid ounces (please weigh it or add it in increments and retest the pH since I'm not sure of the density of granular dry acid). You can add the Borax first, then the dry acid and then after mixing measure the pH to see where it's at.

Though you could try and keep your FC higher at the higher CYA level, that's going to be very hard to do -- that is, keeping around 12 ppm FC. You'll be losing lots more chlorine each day, but it's certainly an option for you. Remember that this is just to minimize the risk of hot tub itch and my numbers were intentionally conservative. You might do just fine at your CYA level with 4 ppm FC (though it's around the level when people started reporting hot tub itch after two months of Vermont-style Dichlor usage). Also, not everyone is sensitive to the bacteria that causes hot tub itch. So you shouldn't be overly concerned if you wanted to just wait until your next drain/refill before having the better (20 ppm) CYA amount.

[I Got My Test Kit....now Some Questions]

I will answer your questions (which I have put in italics below):

Ok, I have had the new tub for about 2 weeks now. I finally got my Taylor kit via the mail order yesterday. I have been using a cheapo kit from my local Home Depot (not the strips but a test kit that used drops for PH and also Chlorine).

Congratulations! You'll love your new kit. It just feels better knowing that the results are more consistent and accurate than other methods.

Here is what I got last night with the Taylor. I had put that morning (approx. 9 hours earlier) the prescribed amount of the sodium dichloro as we had not been in the tub in 4 days. I have as of today switched over to the liquid bleach.

Test Results:

Free Chlorine 2.2 ppm

Combined Chlorine 1.8 ppm

Calcium 30 ppm

The Combined Chlorine (CC) will need to be taken care of. Have you been using a weekly dose of non-chlorine shock (potassium monopersulfate, KMPS)? I suspect not or else you wouldn't have CCs.

CY 65 ppm (This one is hard in my opinion as the more I stare at the tube the more I think I can see the black dot at the bottom but I think this should be fairly accurate.

This is higher than what I normally recommend which is 20 ppm. Did I give you the wrong amount of Dichlor to add? It should have been enough for around the equivalent of 20 ppm FC which would give you 18 ppm CYA. I don't recall if I gave you an amount, but you can calculate it based on label instructions (they say how much to add in weight to raise the FC by a given amount per so many gallons).

PH 7.0 or possible slightly lower

That's on the low side. I'll explain that below when you ask the question about it.

Ok, if I have an understanding of this all I am pretty sure the FC is ok considering it had been sitting all day. I think it should be slightly higher.

With a CYA of 65 ppm you would need to maintain the FC level at around 12 ppm to be equivalent to the CYA of 20 ppm and FC of 4 ppm that I normally recommend. You can certainly run at lower FC, but run a risk of getting hot tub itch. It may be a low risk since the numbers I calculated are theoretical and though we know that the standard use of Dichlor for months leading to nearly 100 ppm CYA or more did cause hot tub itch for several users, I don't know the precise cutoff. You might consider a partial drain/refill to reduce the CYA level closer to 20 ppm and then maintain the FC at a 4 ppm target.

CC I have no idea what this should be normally and I have no idea how to raise or lower this so any help is appreciated.

This should normally be zero. I suggest you shock your tub with a high level of chlorine (say, 20 ppm FC) and keep it uncovered. If you can expose the tub to sunlight, that will help a lot since the same UV radiation that breaks down chlorine appears to also help breakdown CCs.

Calcium is this considered around normal?

Since you didn't add any extra calcium (via calcium chloride) then a low calcium is normal for soft waters. It's around 50 ppm for my tap water. You have to have higher calcium and total alkalinity when you have the water touching ANY plaster/gunite or even grout between tile, but I assume you have none of that in your tub so don't need to add more for that purpose. You can, at your option, add calcium chloride or even sodium chloride salt if you want a silkier feel to the water and less dry skin or folded skin that often happens from being in water for a long time. That is up to you. If you increase salt level, then the CH should not go above 300 ppm and the regular salt level (chloride measured as ppm sodium chloride) will likely feel good at around 1000 ppm. This is purely optional.

My PH has been low off and on so I was using the PH up and it seemed to take care of it. Does the spa products PH up mess with anything else when you add that? Is there something else that is recommended that is better to raise the PH? Is is more common to have to raise the ph than say lower it? Just curious.

The use of Dichlor is actually acidic because the initial addition is only very slightly acidic but the usage of the resulting chlorine is more acidic so the net result is a drop in pH. However, in a hot tub, the pH usually rises from higher TA and the use of jets (more on that later).

I know the dichlor is raising the CY. Is my level ok or too high? I think the liquid bleach does not raise the CY so I should not be raising it anymore as I will just be using the liquid bleach.

See my comments earlier about the CYA level. You are right that Dichlor adds to CYA -- every 1 ppm FC raised by Dichlor also raises the CYA by 0.9 ppm.

What keeps dropping my PH?? Is this a result of the dichlor?

Yes, but there may be other chemicals that are acidic. The non-chlorine shock you mention below is quite acidic.

I have non-chlorine shock that I have used once. Should I used that or do the high concentration of the liquid bleach to "shock"?? Or do you have to switch back and forth?

Well, I am very surprised you have measured CCs if you used non-chlorine shock, but if you used it only once and not weekly then perhaps it got used up. I would stick with a maintenance level of non-chlorine shock. With that, you shouldn't get any significant CCs and won't ever need to shock with chlorine.

We use the tub around 3-4 times per week with 2 people. How often should you shock? I thought about once per week would do it.

You can add a maintenance dose of non-chlorine shock once per week. Remember that this is acidic. HOWEVER, normally with using the tub 3-4 times per week you would experience a rise in pH, not a drop, even with the weekly use of non-chlorine shock. You didn't post your Total Alkalinity (TA) number and I suspect that it might be too low. Normally the problem is that the pH keeps rising too quickly and people need to lower their TA to avoid that, but in your situation you have the opposite problem so your TA is probably too low. Adding a pH Up product should normally take care of that since it not only raises pH, but also TA (if it's sodium carbonate). Please measure your TA number and if it's too low, then add pH Up to adjust pH and if the TA is still too low you can add some Alkalinity Up which is the same as Baking Soda or sodium bicarbonate.

Anyway, look over my numbers and and suggestions are appreciated.

I hope I helped out.

[Water Chemistry And Pool Cleaning Companies]

Maintaining the water chemistry of a pool is actually very easy. It's only when the water is not maintained that it becomes more difficult such as when the chlorine level gets too low relative to the Cyanuric Acid (CYA) level and an algae bloom appears. Using fill water that is high in metals or very high in CH and TA also present special problems, but these can all be resolved.

Pool chemicals vary in their toxicity or danger and are only a problem when in concentrated form. Probably the most dangerous (after chlorine gas, which is usually not used in a residential environment) is Muriatic Acid (31.45% Hydrochloric Acid). Next would come chlorinating liquid (12.5%). I've bleached several pairs of jeans with the latter! Being more careful in pouring, not putting your face near the bottle to avoid inhaling fumes, wearing goggles, and wearing clothes you don't care about are common sense safety methods. And yes, you should not mix concentrated chemicals together in general, but particularly not acid with base (and that includes Trichlor with either Cal-Hypo or bleach or chlorinating liquid). Cal-Hypo, especially at higher concentrations, is flammable and can be dangerous (48% is safest, 65% is just OK, 73% is more dangerous).

The biggest problem you will find is that your training probably doesn't tell you the complete truth. For example, I doubt very much that it says anything about the relationship between chlorine and Cyanuric Acid (CYA) in terms of chlorine's effectiveness. The pool chemical industry claims that only chlorine matters. Let me give you some posts you can look at to learn more. Generally speaking, you should read everything you can on the various pool forums including this site and the Pool Forum and Pool Solutions. You can read more about the chlorine and CYA relationship at this thread and going up one level to the China Shop you can find other topics that might be of interest.

[Help For Newbie]

Essentially, the EcoOne products are enzymes that help break down organics in the water, but as said in the post, chlorine is still needed daily for sanitation. So they essentially replace using non-chlorine shock (potassium monopersulfate, KMPS) for that purpose. I do not know, however, if the enzymes would prevent the production of disinfection by-products of chlorine combined with organics -- I know that KMPS will prevent such by-products. I also haven't compared pricing for EcoOne vs. KMPS.

So it's really about comparing EcoOne vs. non-chlorine shock since both are added once a week and both require daily chlorine addition. Thanks for bringing that option up. I think that anyone using the "Dichlor for a week, then switch to chlorine" will be reducing their disinfection by-products anyway so probably either EcoOne or non-chlorine shock would be effective. I'm not quite sure what problem EcoOne is trying to solve since I didn't think spa users generally complain about combined chlorines or a buildup of organics unless they aren't using a weekly non-chlorine shock. The main advantage I see with EcoOne is that it probably does not build up sulfates in the water (which KMPS does).

[Which Solar Heater Is Better]

The solar disks and solar blanket are very similar. The solar blanket probably retains heat better since there are no holes (open areas) of water exposed to the air. However, a solar blanket requires a reel for storage and is harder to roll and unroll compared to the disks. I have an electric opaque pool cover and it works great, cutting down heat losses at night in half and virtually eliminating chemical losses (from outgassing and breakdown from sunlight) including chlorine during the day (except when we're using the pool, of course). A solar blanket is even better at cutting down heat losses -- probably cutting heat loss to a third or a fourth of what they would be without the blanket.

The solar panels are absolutely, without question, the fastest way to heat your pool water, BUT you almost always want to use solar panels with a solar blanket or else your water will be cold in the morning while being warm in the late afternoon. You can easily lose 4-6 degrees Fahrenheit overnight without a solar blanket if your nights are 50-60F and you keep your pool 85F or so. I have solar panels and they keep the pool at 88F most of the time, though I still lose 2-3F overnight with the thinner electric opaque cover (which is convenient, but less efficient than the solar blanket).

As for whether you need both a solar panel and a solar blanket or whether you can just use a solar blanket alone depends on how warm you want your water, how long a swim season you want, and how hot the weather is in your area.

[Chlorine Options?]

Just a couple of additional comments. If you have an outdoor pool that is exposed to sunlight, then the amount of combined chlorines and disinfection by-products you will get will be minimal. With a salt-water chlorine generation (SWG) system, they will be virtually nil. For an indoor pool or a pool not exposed to sunlight then using an ozone system to oxidize organics is more reasonable, but even then you can use a weekly maintenance dose of non-chlorine shock (potassium monopersulfate, KMPS) instead.

You could also use an SWG system indoors, but need to make sure to use Cyanuric Acid (CYA) in the pool even though it is indoors. The CYA will reduce corrosion rates for metal from the chlorine in salt water.

You should keep in mind that in a pool with Cyanuric Acid (CYA) in it, the amount of disinfecting chlorine in the pool is very low and the production of disinfection by-products is also very low. All reports of asthma and respiratory problems with competitive swimmers and small children have been with INDOOR pools and such pools are not exposed to sunlight and have no CYA in them (and have poor air circulation) even though they probably should (have CYA in them, that is, but the industry currently just thinks that CYA is only useful to protect chlorine destruction from sunlight).

[Yellowish-brown Staining On Steps, Skimmers, Etc.]

It sounds like you were told to add BioGuard Balance Pak 100 which is sodium bicarbonate (same as baking soda). By any chance, was the shock BioGuard Smart Shock? If so, then this is Dichlor which adds both CYA and chlorine, but also has copper in it.

An excess of sodium bicarbonate make your water cloudy and the shock with copper can turn it green. You are seeing yellowish-brown which is usually associated with iron, but the higher pH from what you added could have precipitated that out. They say that you have no copper or iron in the pool, but do you trust your pool store at this point?

If the stains are truly metal, then the way to remove them (other than vacuum to waste for the "easy" stains on the vinyl) is to first add a sequestrant to the water and then to use ascorbic acid (Vitamin C) on the stain (for up to an hour). However, it is necessary to have the chlorine level very low or near zero and to turn off the pump while this is done since chlorine will react with ascorbic acid.

[Is My Ozonator Doing Anything?]

I've been hesitant to respond because I don't have a good answer for this, but since it's been a while with no recommendation, here's my two cents worth. The ozonator should be best at breaking down organic compounds, that is oxidizing, but if you also have an SWG system in addition to an ozonator you'll have to turn off the SWG since it too is good at oxidizing.

I would take a small amount of dye typically used for pools (e.g. "Party Blue") and put one drop in the skimmer with the ozonator running. See if you can see dye color coming out of the returns after allowing enough time to circulate through the system. Perhaps you can first do the test with the ozonator turned off since it should be obvious when the dye color comes out of the returns and how long that takes. Then, turn the ozonator on and repeat the experiment. If you notice a significant difference in having less or no visible dye come out of the returns when the ozonator is on, then this proves it is working very effectively.

On the other hand, one drop of dye might be so much as to overwhelm the ozonator in which case the test may not show the ozonator "working", but that doesn't mean it's not doing anything at all -- just that it can't handle one drop of dye's worth of organics in one pass.

[How Much Bleach Per Gallon?]

The Total Hardness tests for both Magnesium and Calcium. Typically, Calcium Hardness is around 70% of Total Hardness (when both are measured as ppm calcium carbonate which is the typical way these are measured), but this depends on the source of the water.

Only the calcium in the water affects the calcium carbonate water balance that is what you want to achieve in plaster/gunite pools. The magnesium has no effect and is far more soluble. So it is the Calcium Hardness that should be used for pool water balance, not Total Hardness.

[How Much Bleach Per Gallon?]

Yes, you can certainly use your existing test kit for chlorine level (and for pH). It is just harder to know the true free vs. total chlorine level with an OTO kit, but to get a rough idea of chlorine level it's fine. It also doesn't bleach out at very high chlorine levels (say, for shocking) though it won't tell you exactly how much chlorine you have (i.e. it'll just be > 5 ppm).

The FAS-DPD drop-based chlorine test has a precision of 0.2 ppm or 0.5 ppm depending on the sample size you choose to use (so you use the smaller sample size that increments at 0.5 ppm for each drop when you know you have lots of chlorine, say after shocking).

[How Much Bleach Per Gallon?]

The same test kit is used for both pools and spas. The two kits I referred to only differ in their testing of chlorine vs. bromine. What are you testing for (chlorine or bromine) and what kind of "pool test kit" do you currently have or are referring to?

[How Much Bleach Per Gallon?]

The test kit referred to is the Taylor Technologies K-2006 kit you can see at this link direct from Taylor for $71.05. There are other test kits available from other manufacturers as well, but the important thing is to have a test kit that has a FAS-DPD drop-based chlorine test, plus tests for pH, Total Alkalinity (TA), Cyanuric Acid (CYA) and Calcium Hardness (CH). You can often find the Taylor kit at somewhat lower prices at certain retailers including on-line. For example, this link sells the same kit for $59.90 while this link sells the kit for $53.14 and this link has it for $49.00. I have not purchased from any of these retailers and have only purchased from Taylor directly.

If you have a bromine spa, then the Taylor K-2106 is the kit to get instead. It tests for total bromine (using a FAS-DPD drop-based test) instead of free and total chlorine and it does not have the CYA test since that is not needed. Taylor sells the kit for $66.75 and again, I'm sure you can find it online or at some stores for less.

[How Much Bleach Per Gallon?]

Don't worry about the mistake. If I got paid for every time I made a mistake, I'd be a very rich man indeed.

If you kept your spa covered and did not have the jets running, then yes your ozonator is probably working because normally the chlorine wouldn't drop quite that much that fast. If you use the spa, however, then the chlorine can drop very quickly as the combination of heat and aeration can outgas quite a lot of it and much will also get used up by sweat.

[How Much Bleach Per Gallon?]

Something is not right about that. 3 fluid ounces (that's 6 tablespoons) of 6% bleach in 300 gallons should raise the FC by 4.8 ppm (about 5 ppm). You saw double that. That either means that the bleach was closer to 12% (unlikely, unless you use chlorinating liquid which indeed is around 12.5%) or the spa is closer to 150 gallons. It is also possible that the chlorine was not fully mixed in the water, though if you had the pump circulation on it should get mixed rather quickly.

I think I found at least a partial answer. Look at this link where it says that your Catalina CL Series 300 spa has a water capacity of 190 gallons, NOT 300 gallons. Of course, this link could be wrong. Next time you refill your spa, see if you can measure its capacity. If it's filled with a hose or through some inlet, time how long it takes to fill a large bucket and then time how long it takes to fill the spa.

[Asthma From Bromide?]

Some people do report a sensitivity to bromine, but if that turns out to be the case for you all is not lost since there is very little sensitivity to chlorine so you could switch to using chlorine instead if you had to. Chlorine has its own issues, mostly in being harder to maintain levels so you have to add it every day or two (depending on how frequently you use your spa). If you use chlorine, you'll need to use a non-chlorine shock as well and will want to start by using Dichlor for a week or two and then switch to bleach, until the next time you change the water.

[New Spa Owner]

Though the risk is low, when the chlorine is gone in the hot tub because the ozone has used it up, any bacteria or algae stuck to spa surfaces in biofilms can grow. [EDIT] The generation rate for most bacteria is from 15 minutes to one hour so that is how long it takes to double in population. One bacteria can turn into over 16 million bacteria in from 6 to 24 hours. [END-EDIT] Only water that circulates and flows through the ozonator gets hevaily zapped with ozone. The ozone does not leave a residual in the spa water.

I agree the risk is low, but the above scenario is part of the reason why chlorine is required with ozone systems. The main reason, however, is killing pathogens introduced by bathers preventing transmission from one to another. The ozonator doesn't help there -- only a residual amount of sanitizer (chlorine) takes care of that.

[New Spa Owner]

Ozone is beneficial with any chlorine or bromine schedule.

Ozone tends to break down chlorine while it does not do so for bromine (and in fact tends to reactivate bromide back to bromine). So I would say that ozone is quite compatible with bromine, but is less so with chlorine. It certainly works, but you may be adding more chlorine with an ozone system than without. If you've got lots of organics and potential algae in your water, then the ozone will take care of those instead of the chlorine so you would need less chlorine, but some users on this forum who have used ozone seem to report fairly high chlorine usage/loss with their systems (even when covered with no jets on which is when chlorine is typically used up faster).

[Is Bromine Out Of Style And Why?]

I'd like to add a comment to something Trigger mentioned about adding chlorine after getting out of the spa and letting the sanitizer drop to low levels while in the spa. Since the high levels of chlorine (ignoring the Dichlor CYA issue for the moment) will kill pathogens in the water, if you only use the spa by yourself then you are less likely to be introducing anything into your spa that will cause a problem right away. When you get out, any bacteria you introduce are then killed when you increase the chlorine level.

The issue is more with what happens when multiple people share a spa. In that case, the main reason for maintaining a recommended chlorine level while in the spa is so that any bacteria that are introduced are killed rather quickly and not passed from one person to another. This isn't just about skin contact either, but is mostly the (I apologize for the terms) fecal-to-oral route as that is the path for many of the pathogens found in pools and spas that are not sanitized sufficiently. The generation rate for most bacteria is from 15 minutes to an hour so that means a doubling in the size of the population. A single bacteria can reproduce to over 16 million bacteria in 6-24 hours.

So, having higher levels of disinfectant is clearly important in a commercial pool or spa environment where many people are sharing the same body of water. It is less important in residential pools and spas, but I wouldn't say that it is of no concern. The people who got hot tub itch (which is often passed from place to place via swimsuits) I am sure would like to do whatever it takes to avoid it.

[Is Bromine Out Of Style And Why?]

104 Degrees,

Regarding the color on your chlorine test strips, ALL sources of chlorine will register identically on ALL chlorine tests because they all produce identical disinfecting chlorine in the water. The chlorine tests don't actually test the instantaneous disinfecting chlorine level, but rather the entire chlorine reserve which includes the chlorine attached to CYA. This is known as the Free Chlorine level.

So you don't need to get new chlorine tests, but I would suggest considering getting a good overall test kit such as the Taylor K-2006 or at least get a standalone FAS-DPD drop-based chlorine test kit. It is much more accurate than strips. Strips work well for some types of tests, such as borates or pH or salt, but aren't so great with the other tests.

[Is Bromine Out Of Style And Why?]

waterbear answered your questions, so I'll just add a little more. Due to the process of making bleach or chlorinating liquid (both are sodium hypochlorite), for every 1 ppm FC you get about 0.8 ppm of salt. When the chlorine breaks down or disinfects or oxidizes, it gets converted to chloride where you end up with another 0.8 ppm of salt, so the net effect is that for every 1 ppm FC you get 1.6 ppm of salt. By comparison, with Dichlor, for every 1 ppm FC you get 0.8 ppm of salt after the chlorine is used up (so using Dichlor introduces half the salt compared to bleach). And as waterbear said, there is a very small amount of sodium hydroxide (lye) as well that increases the pH slightly to help stability of the chlorine. Though the initial addition of chlorine is alkaline (makes the pH rise), the usage of chlorine is acidic (makes the pH drop) and the net effect is almost exactly neutral -- just an immeasurable rise in pH from the extra sodium hydroxide (1 ppm FC after usage has a net pH rise of only 0.002).

Even with relatively high CYA from using Dichlor exclusively and having only 1 ppm FC at times, your spa is still probably bacteriologically safe for "easy-to-kill" bacteria such as E.coli and other heterotrophic bacteria because they really are very, very easy to kill. Algae takes more chlorine to kill or keep away, but with spas that are generally covered so that there is no sunlight, this is less of an issue. The primary problem with spas is the bacteria Pseudomonas aeruginosa which causes "hot tub itch". As I said in an earlier post, it's a statistical probability, not a certainty, that by using Dichlor exclusively that you will get this bacteria. There is no such thing as spontaneous generation so if you don't introduce that bacteria into your spa then it will not appear out of thin air, but in your spa after a month or two of Dichlor, any such bacteria that gets introduced is going to have a decent chance of surviving. Finally, even if you have that bacteria already in your spa, it does not mean you will notice it since not everyone gets a reaction from this bacteria.

When I look at pool water chemistry I do not look at just data for my own pool or even a few friends. I scour every pool forum I can plus official studies of data to look for patterns. With bacteria and algae you can't say that a pool or spa that is free of it has conditions that prevent it, but you CAN say that a pool or spa that has measurable bacteria or visible algae has conditions that do NOT prevent it. Like much of science, no number of examples can prove a theory to be absolutely correct, but one clear example can prove a theory wrong (or can provide other dimensions or parameters that need to be taken into account).

One of the links I provided leads to this link that describes a Commercial Spa Study that showed that high CYA levels with insufficient chlorine are bacteriologically unsafe. Unfortunately, the study is small enough that one could also conclude that just having too low an FC level is a problem but this conclusion is inconsistent with the basic chemistry that is involved and with other studies. Though this study might conclude that a disinfecting chlorine level of 0.02 is sufficient, the actual CT (chlorine concentration times time) number for the hot tub itch bacteria (30-50 for 4-log kill compared to 0.08 for 2-log kill for most bacteria -- see this link for more info) would indicate that 0.10 is a better number to use. I do not claim that the 4 ppm FC and 20 ppm CYA recommendation I am making is ideal, but I believe it to be effective. Perhaps I am being too conservative, but if you look at the links of real spa users who used Dichlor for months and developed hot tub itch (or hot tub lung) then this would indicate that clearly the level of disinfecting chlorine in their spas was insufficient to kill this bacteria.

If you added 3 ppm FC 2.5 times per week, then this would add 32 ppm CYA per month. That's not so bad, especially for the first month. However, by the end of the third month you are close to 100 ppm CYA and the combination of 100 ppm CYA and 1 ppm FC has less than 5% of the disinfecting chlorine as my recommendation of 4 ppm FC with 20 ppm CYA. The people who reported getting hot tub itch seemed to be adding more chlorine than you have -- they added about 3-4 ppm FC per day and they used their spas every day (which is probably why they used more chlorine -- running the jets has more chlorine outgas). So they were seeing monthly increases in CYA of 65 ppm CYA or about double what you were. So maybe the "cutoff" for a sanitary spa against hot tub itch is actually closer to where your spa is at the end of 3 months which would be around 1.5 months for these users. Or maybe you were just lucky with your spa or are not sensitive to this bacteria.

If the users who had hot tub itch follow my recommendations and again get hot tub itch, then this would prove that my recommendation is either wrong or insufficient to kill this bacteria. If they do not get hot tub itch, then it does not prove me right, but simply adds more evidence to support the theory.

[Is Bromine Out Of Style And Why?]

The bleach must be unscented without other additives. Clorox Regular bleach that says 6% on the label (it also says 5.7% available chlorine) is actually registered with the EPA for use in pools, though they didn't bother to do that with spas since the volume is so low. You can use other unscented bleach, but some really cheap brands may be only 3% chlorine and don't guarantee their concentration.

It takes 2.5 fluid ounces (5 tablespoons) of 6% bleach to raise the FC by 4 ppm in a 300 gallon spa. If you use a cheap brand with an unknown concentration of chlorine, then you'll have to experiment to see its effects. Since you use so little chlorine, I think just paying a little more to get the Clorox bleach is worth it.

By the way, for those who want the water to feel silkier and also to provide some additional pH buffering and algae prevention, you can use 30-50 ppm Borates which you can add from 20 Mule Team Borax. It takes about 8 ounces weight (about a half of a cup or 4 fluid onces) of Borax to get to 30 ppm in a 300 gallon spa. You also need to add about 7 ounces weight (about 2.7 fluid ounces or 5.5 tablespoons) of dry acid (sodium bisulfate) to compensate for the pH since Borax raises the pH. This has been done in pools with great success. You can read more about that in this thread. Thanks to waterbear for doing the research on this.

[Is Bromine Out Of Style And Why?]

I wouldn't say I'm a fan of using ozone (O3), but I'm not against it. If ozone didn't break down chlorine, then I'd say it was an excellent addition to using chlorine and would be simply a cost/convenience tradeoff. You can certainly accomplish everything that ozone does by using chlorine and MPS alone (in a spa -- in an outdoor pool MPS isn't needed, at least not as much, due to sunlight which, of course, has UV light). Unfortunately, because the ozonator breaks down chlorine, it makes the decision more difficult. I'm not really for or against it for that reason.

As for Nature2 (N2), that isn't as useful. It's not that it doesn't work, but that it can't be used alone and costs a lot so why bother. The system works by putting [EDIT] metal [END-EDIT] ions into the water. Copper ions are pretty good at preventing algae, but they also tend to make hair have a green tint. Silver ions kill bacteria, but rather slowly, and they don't kill other types of pathogens as well. So the N2 system requires the use of a chlorine residual as well, though such residual can be lower than if N2 were not used.

I'd say that if you aren't allergic to bromine, then that's an excellent option since it is relatively low maintainence though it does cost more than chlorine. If you want the lowest cost or are allergic to bromine, then using chlorine as I recommend (Dichlor initially, then switch to bleach) is an excellent option. Using Bacqua is expensive and has longer-term problems, but those are mostly mitigated by the changing of the water every few months in a spa (so the Bacqua issues are worse for pools since you don't change the water regularly). If you want the convenience of Bromine but are allergic to Bromine, then Bacqua may be a decent choice. Note, however, that some users have reported bad experiences with Bacqua while others swear by it. With bromine and chlorine, used properly, both sets of users tend to like these systems and the choice is more one of higher cost greater convenience or of allergic sensitivity.

[Is Bromine Out Of Style And Why?]

My responses to your questions below.

In esscence, your claiming that you need CYA (muble muble acid) in order to stablize the chlorine so that it can last longer and sanitize the spa (kill organic matter). Did I get that right?

Yes, this is essentially correct, but the CYA not only increases the life of the chlorine, but it decreases its effectiveness. So there is a tradeoff that must be balanced.

Dichlor doen't last that long in the tub, and your belive that it's effective time is too little to properly sanitize the tub? I raise my Cl to 5ppm after soaking and have good luck.

Actually, using only dichlor should have the chlorine last longer especially after a few months of use due to the buildup of CYA. The fact that you see the Free Chlorine (FC) level drop from 5 ppm to 1 ppm so quickly is unusual with high CYA levels (but explained below due to your use of an ozonator). So the way to think about it is that with using only Dichlor and adding enough to get to 5 ppm FC, you have a large "reserve" of chlorine, but the "active" amount of chlorine on the front lines, so to speak, is too low. I don't think your chlorine drop is due to it getting outgassed since you have high CYA levels (due to using only dichlor).

At high temps, it's my understand bleach is even less effective than dichlor, and I've heard it's damaging to the filter media. What was the benifit of bleach again?

Unless you used ONLY bleach, then such claims are just B.S. The chlorine in dichlor and in bleach when both are in the water ARE IDENTICAL. Dichlor is simply CYA plus chlorine combined into a single compound. When in water, both are there and it doesn't matter if the chlorine source came from bleach or from Dichlor, at least as far as the chlorine is concerned. But the Dichlor adds CYA and THAT causes the chlorine to become less effective as the CYA combines with chlorine to form new compounds (that I've called Cl-CYA in this post). If you didn't use Dichlor at all and had NO CYA in your pool whatsoever, then using bleach to get to, say, 4 ppm FC would be a rather high level of disinfecting chlorine and it would degrade swimsuits faster. It *might* slowly degrade cartridge filters a little faster, but I doubt it would do anything to sand or DE (speaking more generally about pools as well as spas). My wife experiences this problem with her swimsuits where she uses an indoor pool where they use no CYA and they deteriorate every winter. When using our own pool in the summer, where I have about 20 ppm CYA in the pool, her swimsuits show absolutely no sign of wear whatsoever.

This is one of several reasons why I suggest using SOME dichlor initially to get the CYA up to around 20 ppm. Then, if you maintain an FC level of 4 ppm minimum, then the amount of disinfecting chlorine is the same as if you used 0.23 ppm FC with no CYA. If you continued to use Dichlor, then your CYA would keep building up and the disinfecting chlorine level would continue to go down. At 100 ppm CYA and 4 ppm FC, the disinfecting chlorine level is only equivalent to 0.04 ppm FC with no CYA. At 200 ppm CYA and 4 ppm FC, the disinfecting chlorine level is only equivalent to 0.02 ppm FC with no CYA. That's over a factor of 10 less than the minimum level I recommend that ensures the killing of the bacteria that causes hot tub itch.

I think many poeople who have "hot tub itch" are really suffering from improper water balance (PH being off), or perhaps have a alergic reation to dichlor (I've heard the same that some folks react poorly to bromine). Other folks Ive found were simply soaking in too high concentrations (6pp plus), and it was just stripping the oils from the skin.

Though this is, of course, possible, I believe it very unlikely that people are allergic to dichlor as it is simply CYA plus chlorine and this combination is used in virtually ALL outdoor pools even though it is usually provided as trichlor or as chlorine and CYA separately. In the water, it all ends up being the same set of chemicals. You are right that some people have a sensitivity to bromine. As for 6 ppm plus, if they were using Dichlor for months, you could be in 20 ppm and not have any problem. There simply isn't enough disinfecting chlorine to attack your skin at rates fast enough to be a problem. Now 20 ppm isn't something you'd want to drink regularly since the chlorine attached to CYA will get released as it gets used up, but just remember we're talking two separate things here: the RATE of chemical reactions which is based on the disinfecting chlorine concentration and the RESERVE AMOUNT of chlorine that is available over a longer period of time as chlorine gets consumed.

By the way, the first day you add Dichlor to get to 5 ppm, the disinfecting chlorine level is equivalent to 2.2 ppm FC with no CYA. After adding more dichlor to get from 1 ppm to 5 ppm (so adding enough for 4 ppm FC) you now have the equivalent of 1.2 ppm FC with no CYA. After the third addition of Dichlor, you have the equivalent of 0.7 ppm FC with no CYA. After the fourth addition, you have the equivalent of 0.5 ppm FC with no CYA. After the fifth addition, you have the equivalent of 0.3 ppm FC with no CYA and are about where my recommendation is (you have accumulated 19 ppm CYA). In other words, in the first 4-5 times you are in your hot tub after refilling with water, you are actually exposed to higher levels of chlorine than what I am recommending you maintain after switching to bleach.

Just because your spa has too low a disinfecting chlorine level to kill the bacteria that causes hot tub itch, that doesn't mean that you are certain to get it. It's a statistical probability sort of thing -- it just increases the likelihood, that's all.

I never tested for cya, I use ozone and dichlor and shock with MPS ever 2 weeks, all in all I have good luck.

With the ozone and the MPS shock, you breakdown most organics before chlorine gets a chance to combine with them and that is a good thing. This helps prevent forming monochloramine and getting smell from that and even more importantly it prevents even worse (carcinogenic) disinfection by-products from forming. I recommend the weekly use of MPS shock, but that's for those without an ozonator. Your ozonator provides some of that oxidation capability so using less MPS is fine.

Now I understand why you are using up your chlorine so quickly even with high CYA levels after using only Dichlor. It's the ozonator. Ozone will breakdown chlorine. What I don't know is whether it will also break down CYA or the Cl-CYA compounds, but I suspect it might since it is rather powerful and CYA is technically just another organic compound.

Also, any free-floating bacteria that causes hot tub itch is probably going to get killed by your ozonator. So the primary reason you haven't had any problems with using only Dichlor is that you also have an ozonator. None of the people who reported hot tub itch (or hot tub lung) used an ozonator and they just used Dichlor exclusively.

Ozonators have benefits, as just described, but they also consume chlorine and overall cost more. Nothing wrong with that -- it's just a tradeoff between cost and possibly convenience, similar to the purchase of an salt water chlorine generator for a pool.