Is My Water "old" - Time To Change?

[simonc]

My situation:

I have a small (3 person) Jacuzzi Brand spa. It has has an ozonator and I use chlorine. My wife and I use the spa about 4 times per week. When I start out with "new" water, I find the chemistry (chlorine and ph levels) easy to maintain. As my water gets "older" I find it harder to maintain. I have to add ph+ often. The test strip chlorine colors are off (after a few seconds the patch turns dark brown instead of the normal colors I get when the water is "new"). I have to stop using the test strips and use the droplet kit which shows that the chlorine level is OK, even though the strip turned a weird color. It seems that as the water gets "older", the more frequently I have to add chemicals to keep the water from going cloudy.

My thinking:

It seems to me that over time, as I add chlorine, ph+, non-chlorine shock, etc.. the water gets saturated with chemicals, i.e. the water is getting "old". This takes about two or three months of use. Since I live in California and we are having a drought, I feel guilty about using a few hundred gallons of water to change my spa water.

My questions:

How do I know when to change the water? Is there anything (procedure/chemical/device) that will prolong the "life" of my spa water?

Thanks,

- Simon

[chem geek]

Are you using the Dichlor-then-bleach method? If not, then read this post since that method can usually have you go about twice as long before changing the water.

[simonc]

Are you using the Dichlor-then-bleach method? If not, then read this post since that method can usually have you go about twice as long before changing the water.

Chem Geek -

Thank you for the link to Nitro's writeup on spa chemistry. No, I'm not using the Dichlor/Bleach method.

In all honesty, I found the writeup somewhat overwhelming ... seems like a lot of work just to soak my tired body at the end of the day. I don't think all the chemicals & testing are for me. Is there a simpler method that will work?

One of the things that I found interesting about Nitro's writeup is that he states that spa pH has a tendency to drift up over time - to the more base values. My spa is always drifting down toward the more acid levels. As my water gets older, I'm adding pH+ a couple of times a week. Is there something I'm doing wrong that would cause my spa to behave in the opposite manner of most others?

I should have mentioned that I live in hard water area. My water is from a municipal source but their water comes from well water. Also, I use a floater to dispense the chlorine tablets (trichloro). I supplement it with granular (dichloro) after heavy use or if the water starts to turn cloudy. Also, the temp range is usually 97-100. When we are actually in the spa, we increase the temp to 104, then let it drop back down when we get out.

So ... assuming that I'm NOT going to do all the work Nitro suggests (I admit it ... I'm lazy) ... my new questions are:

1. After refilling my spa and getting the chemistry right, would I better off using bleach instead of the chlorine tablets/powder?

2. Why does my spa pH constantly drift down requiring me to add pH+ frequently after the water is about 2 months old? (Note: I adjust my alk level before adding ph+.)

3. Any other tips that would make spa care both more effective and easier?

4. I assume the major reason for switching to bleach is that it does not contain stabilizers. I've heard that stabilizers build up and then the chlorine is not as effective and therefore greater amounts are required. Correct???

Thanks,

- Simon

[Dnepr Dave]

I use Nitro's Diclor/ Bleach method, and only check the tub with test strips about once a week. My tubs readings don't change much, if at all, in a week, so why waste strips?

I think Nitro was just being very thorough with his description, it is not as complex as it might seem.

I use rainwater collected from my roof and filtered through a whole house sized charcoal filter. I add Dichlor until the CYA level it about 30 to 50 ppm, then switch to Clorox bleach, I pour a little bit in after each soak, the free chlorine and total chlorine stay the same (<5ppm) and the PH stays right at 7 and I have been changing water about every 6 months. I could go longer, but after a good rain, my cistern is full and I figure it is a good time to freshen up the spa!

Dave

[chem geek]

Simon,

Your use of Trichlor is the primary cause of the pH tending to drift downward. If you used more Dichlor and less Trichlor, then the pH would be more stable (though the rate of Cyanuric Acid increase would be faster).

After refilling your spa you do NOT want to use bleach initially. You can initially use Dichlor and then after a couple of weeks switch to using bleach. That's really the core of what Nitro described. However, to minimize the rate of pH rise after switching to bleach, you would need to keep your Total Alkalinity (TA) lower. Right now because of the Trichlor, I suspect you are adding pH Up frequently so that also increases TA. Adding 50 ppm Borates from Gentle Spa also helps.

Your pH is dropping faster after a couple of months because more of your measured TA is composed of Cyanuric Acid (CYA) from your continued use of Trichlor and Dichlor. So there are less carbonates in the TA and these would counter the pH dropping from the Trichlor. You could let your TA target increase over time to compensate for this, but really having so much CYA in the water makes the chlorine less effective so yes, you are correct about that.

Richard

[simonc]

Richard -

Thanks for the very helpful info. Like most things in life ... there is no free lunch ... If I want my water to last longer, I'm going to have to do some work - giving up on the chlorine floater and more monitoring/testing.

My wish for my spa and for California is that we have a normal winter that will end our drought ... not too wet ... or parts of California will slide away.

Thanks,

- Simon

[Nitro]

Simon,

My writeup may seem overwhelming at first, but the process is really not. As a mater of fact, after reading the full post, the summary at the end is all you really need to refer back to. Think of it like driving a car. It is a bit of a learning curve, but once you learn it, it becomes easy. Not to mention, if you don't learn it, you're going to continue to have problems and spend more time maintaining your water.

After my inital startup balance (takes a day) and Dichlor addition (for a week or two), I add Bleach after each use (3-4 times a week). I check pH once a week, and add Acid if needed (which btw is rare). I sometime use MPS during hot tub partys to help out the Chlorine, but it's not needed. My water is going on 5 months old and I have zero problems. The bottom line is, if you use your tub often there is no easier way to maintain your tub.

Hope that helps.

[simonc]

Nitro -

Thanks for taking the time to look at my situation. Also, I appreciate your knowledge and experience with the rest of us.

In your writeup (Nitro's approach to Water), you say:

"Important: if you're not willing to test your tub everyday, at least for the first month or two, this method is not for you. I'd recommend another sanitation method"

So I figured this in not for me, but I'm willing to see if it might work, if I can simplify the process, if possible.

Some questions:

1. "clorox unscented" is clorox "regular" liquid bleach that one buys at the supermarket. Correct?

2. I'm a little confused as to how to determine when to switch to bleach. You recommend 20-30 ppm of CYA. Hitting this target seems to require constant testing of FC. Can I just "ballpark" it? Use Dichlor for 2 weeks then switch to bleach? I have a small 3-person Jacuzzi brand hot tub. I think it holds about 250-300 gallons. It would be nice if based on 100 gallons, one could know how much dichlor needs to be added to reach the CYA goal. For example, if 1/x cup of dichlor would produce 25 ppm of CYA in a 100 gallons of water, then I would put 3 x 1/x cup in a container. I would add dichlor (as needed) from that container everyday until the container is empty, then switch to bleach. Maybe I'm just dreaming?

4. I assume that CYA level does not change significantly once I stop usng dichlor. Correct?

5. For a small tub like mine. About how much bleach do I need to add on a daily use basis? 1/8 cup? 1/4 cup?

Thanks for your help,

- Simon

[simonc]

Dave -

Your experience with the Dichlor then Bleach method is encouraging. I think I'll give it a try.

- Simon

[Nitro]

Nitro -

Thanks for taking the time to look at my situation. Also, I appreciate your knowledge and experience with the rest of us.

In your writeup (Nitro's approach to Water), you say:

"Important: if you're not willing to test your tub everyday, at least for the first month or two, this method is not for you. I'd recommend another sanitation method"

So I figured this in not for me, but I'm willing to see if it might work, if I can simplify the process, if possible.

When you first learn this method it's recommended to test FC everyday for at least a month, so you learn how much Chlorine you're using. After you get the hang of it, you can test FC less frequent. You can even use Test Strips to get quick FC estimates. That only takes 15 seconds. Then main thing to remember is to ALWAYS have FC above zero. If you do that, your problems will be few.

1. "clorox unscented" is clorox "regular" liquid bleach that one buys at the supermarket. Correct?

Correct

2. I'm a little confused as to how to determine when to switch to bleach. You recommend 20-30 ppm of CYA. Hitting this target seems to require constant testing of FC. Can I just "ballpark" it? Use Dichlor for 2 weeks then switch to bleach? I have a small 3-person Jacuzzi brand hot tub. I think it holds about 250-300 gallons. It would be nice if based on 100 gallons, one could know how much dichlor needs to be added to reach the CYA goal. For example, if 1/x cup of dichlor would produce 25 ppm of CYA in a 100 gallons of water, then I would put 3 x 1/x cup in a container. I would add dichlor (as needed) from that container everyday until the container is empty, then switch to bleach. Maybe I'm just dreaming?

Not recommended to add it all at once because the FC will be too high. You don't have to measure FC everyday to calculate CYA. Just remember for every 10 ppm FC you add, you also add 9 ppm CYA. So after ~30 ppm FC, you should be good to go. Use the Pool Calculator to calculate how much Dichlor is needed. BTW, this doesn't have to be exact. Anywhere between 20-50 ppm CYA is fine.

4. I assume that CYA level does not change significantly once I stop usng dichlor. Correct?

Not much. However, it can decrease over time, because of splash out and other reasons (I don't know.) Therefore it's good to check CYA every few months. If it's low, just use a little Dichlor to build it back up, then switch back to bleach.

5. For a small tub like mine. About how much bleach do I need to add on a daily use basis? 1/8 cup? 1/4 cup?

That depends on how much you use the tub, among other factors. This is why you need to test FC everyday for a few weeks until you figure it out. With two clean people using the tub for an hour, I'd guess it would be more like a half to a full cup per use, and 1/4-1/2 cup per day without use. Again, these are just estimates. Just remember, tub size doesn't matter. It still requires the same amount of chlorine regardless of the tub size, because the same amount of waste is put into the tub by the bathers.

[Nitro]

Dave -

Your experience with the Dichlor then Bleach method is encouraging. I think I'll give it a try.

- Simon

You really have nothing to lose. I think you'll find it much easier (less fuss or problems) than what you were doing.

[simonc]

Nitro -

Thanks for your detailed reply to my questions. I'll give the Dichlor/Bleach method a try.

If you (or anyone else) has the time/patience, here are a few more questions:

1. I have a ozonator about 4 years old. How do I know if it is working? When I capture the bubbles in an inverted glass, it just smells like regular air to me (and my wife). I thought ozone was suppose to have a a strong acrid smell. Do ozonators really reduce chemical use and if so, how do I know if mine is not just blowing plain old air bubbles.

2. The salesman at the spa store tried to sell me on using a silver nitrate cartridge (placed inside one of the large spa filters) as a way of reducing chemical usage/buildup. $35 dollars for a single cartridge that's suppose to last for 4 months. Silver nitrate is nasty stuff (can leave black marks on the skin) ... but then again chlorine isn't very nice either (possible chemical burns in high concentration). Any thoughts on using Silver nitrate to reduce chlorine usage and make the water last longer?

3. Your writeup mentions MPS (Potassium Monopersulfate - non-chlorine shock) as lowering pH. My water pH drifts down (toward the acid end). Maybe I'm using too much non-chlorine shock? However, the type I use is Sodium Persulfate (made by Spa-Kem). Is this the same as MPS and will it also lower pH? Maybe I won't need to use it as often with the Dichlor/Bleach methdod?

Thanks,

- Simon

[mcw53]

Hey Simon -

I'm a relative newbie to all this, but would like to share my thoughts and experience. I purchased a new 450 gallon Hot Spring Envoy spa in May. After a couple months of struggling with water quality using the BaquaSpa system, I discovered this forum. After a week of digesting Nitro's and chem geek's posts, I decided to switch to a chlorine based sanitizing system. My dealer provided me with new filters, Spa Purge, dichlor, a Nature2 cartridge and MPS. After decontaminating using Nitro's procedure, I initially started with the Nature2 low chlorine recipe. I also had the ozonator turned back on since it off while using Baqua. With the Nature2 cartridge installed in the circulation filter and maintaining the proper levels of MPS, adequate sanitation is achieved as evidenced by the EPA approval of this method. Even so, I decided to supplement with chlorine. My wife and I soak 20-30 min/day, 6-7 days a week. About every 3rd day, I use dichlor instead of MPS. After adding ~40 ppm FC (36 ppm CYA), I switched to bleach.

The ozonator and MPS takes care of the heavy oxidation work, thus allowing the silver ions from the N2 cartridge and very low levels of chlorine take care of the sanitation chores. As suggested by Nitro, I keep a squeeze bottle of regular Clorox (6% sodium hypochlorite) by the hot tub. I have well defined 1 oz marks on the bottle. After a soak, I squirt a couple oz into the hot tub (1 oz ~ 1 ppm FC in 450 gal). A side benefit to using bleach is that it will raise the pH. On MPS alone, I had to occasionally add sodium carbonate (soda ash) to up the pH and/or sodium bicarbonate (baking soda) to up the TA. Since using bleach I have not had to add either. pH stays in the 7.4-7.8 range with TA at 60-80 ppm. My CH is ~180 ppm.

Also, I would highly recommend adding 50 ppm borates. I use ProTeam's Gentle Spa for this.

I would also recommend using a high quality (pure) MPS product such as SeaKlear (45.2% with 4.7% active oxygen).

Be willing to test frequently, at least until you know the effects of what you put into your spa, including yourself. I'm on day 45 and now only test once or twice a week. Water still sparkles like on day one. You'll surprise yourself on how quickly you pick this up.

Hope this helps …

[simonc]

mcw53 -

Thanks for sharing your experience and advice.

A question about MPS ... you said:

"With the Nature2 cartridge installed in the circulation filter and maintaining the proper levels of MPS ..."

Isn't MPS the non-chlorine shock which is used to oxidize some of the left over chlorine chemicals and such? Is there "a proper level" of MPS and how do you determine/test for the level?

Lastly, do you think the Nature2 silver nitrate cartridge makes a real difference in lowering chlorine use?

- Simon

[chem geek]

The N2 won't change the chlorine usage since the metal ions are not oxidizers. They are weak sanitizers (weak in the sense that they kill more slowly than chlorine) so are like insurance in case the chlorine gets too low. That also helps protect you while soaking even if you soak with minimal or no chlorine. Many people add their chlorine right after their soak such that when they next get in the chlorine level is down to around 1 ppm or so. With N2, the time with the low chlorine levels at least has some auxiliary protection.

MPS, non-chlorine shock, is an oxidizer so will reduce chlorine usage, but it's more expensive than chlorine and chlorine can pretty much do the same thing. With N2, MPS at sufficiently high levels can be a sanitizer as well -- the combination of silver ion with MPS at high temperatures (100F-104F) is the key to the low or no chlorine recipe of Nature2 where chlorine is only used "as needed" if there is further oxidation required (i.e. if the water gets cloudy or dull). It's a different approach. One could use Dichlor-then-bleach by itself or use it in conjunction with Nature2 and in either case one need not use MPS. These are personal choices to make.

[simonc]

MPS, non-chlorine shock, is an oxidizer so will reduce chlorine usage, but it's more expensive than chlorine and chlorine can pretty much do the same thing ...

Richard -

Once again, thank you for sharing your knowledge and experience with me. It looks like I've got a lot to learn.

I thought non-chlorine shock's primary purpose was to remove (via oxidation) all those chlorine residuals that cause the water to smell bad. Am I wrong? I use the "non-chlorine shock" made by Spa-Kem - sodium persulfate 75%. I don't think this is the same as MPS. Am I using the wrong kind of non-chlorine shock?

Anyway ... here's my plan:

1. I'll get a better test kit like the one you recommended.

2. I just changed my water and I'm using Dichlor granuals now. No more Trichlor floater - except when we go on vacations for more than a couple of days.

3. When I get the right CYA level, I'll switch to bleach and see what happens.

I'm still debating whether or not to use a silver nitrate cartridge in ADDITION TO the above. If the $35/cartridge would help me reduce chlorine use and/or make spa maintenance easier, I would use it. However, it's hard for me to believe that in such low concentrations the silver will actually make a difference. I have nothing against saving money, but my primary concern is to keep my water "pleasant" and clean as long as possible - in excess of 3 months. I'm willing to spend the money for the silver cartridge if it really will help me do that.

Thanks,

- Simon

[chem geek]

Standard non-chlorine shock is potassium monopersulfate (MPS). What you are using is sodium persulfate which is an even stronger oxidizer that is very irritating to some people. In fact, it is the small amount of persulfate contamination in MPS that makes it irritating immediately after its usage. If you are going to use persulfate, then having a silver cartridge would help since silver catalyzes the breakdown of persulfate. Of course, if you used regular MPS then the silver wouldn't be as needed.

You are correct that if there is MPS in the water and you sweat (or urinate), then the ammonia and urea will get oxidized by MPS before chlorine gets a chance to combine with these to produce combined chlorine such as monochloramine that smells. However, as I said before, most people don't soak with high chlorine levels so don't get that smell. So using MPS along with chlorine is certainly an option so that you could soak with more chlorine and not get the side effects of chloramines. This is all a cost/convenience tradeoff.

MPS, as well as persulfate, will register as CC in the chlorine test and at higher levels (and possibly with even lower levels of persulfate) it will register as FC. So you'll need an interference remover when using MPS to really know the chlorine level. If you have a silver cartridge, then this isn't as important since the MPS will sanitize in that situation.

[simonc]

Chem Geek -

Thanks for the explanation. I think I'm going to stop using the non-chlorine shock. Also, I did not realize that there are two different kinds of the stuff.

I was under the misimpression that non-chlorine shock got rid of the build up of "old chlorine" chemicals that were no longer active (i.e., not contributing to the free chlorine that sanitizes). Based on this, I figured that the non-chlorine shock was getting rid of chemicals that made my water less pleasant. I guess I was really doing just the opposite.

My preference is to add as few chemicals as possible/necessary. I'll try the dichlor then bleach method, as you (and Nitro) suggested. I don't see a need for MPS. If my water turns cloudy, I'll just "shock" the water with more chlorine (bleach) than usual.

I'm still debating the use of the silver nitrate cartridge. I posted a separate thread on this forum to get feedback from people who have actually used silver in their tubs - so far no responses. I'm a little nervous about silver nitrate in a cartridge. From my very limited experience in chemistry class, I remember it as nasty stuff that can turn your skin black. I don't know how the cartridge works or if it can fail (i.e., release too much silver nitrate at one time into the water) and turn my skin black ... the stuff of nightmares.

Happy soaking ...

- Simon

[chem geek]

There are quite a few spa users who use Nature2 which is a mineral cartridge (silver and copper, I believe), but it does not lower chlorine usage (unless you use MPS instead, but that's even more expensive) and it is not an oxidizer. It's purpose is to supplement sanitation. The absolutely least expensive way to sanitize and oxidize bather waste is to use the Dichlor-then-bleach method. However, the pH tends to rise when switching to bleach so it is best to use 50 ppm borates in the water, such as from Gentle Spa, and to have the Total Alkalinity (TA) be lower (as low as 50 ppm, if necessary). So factor that into total cost. You should be able to go twice as long before changing the water so the amortized cost of the Borates should be fairly low. You can also buy Boric Acid directly at possibly lower prices, but since the quantities are low it's probably easiest just to get Gentle Spa.

[mcw53]

A question about MPS ... you said:

"With the Nature2 cartridge installed in the circulation filter and maintaining the proper levels of MPS ..."

Isn't MPS the non-chlorine shock which is used to oxidize some of the left over chlorine chemicals and such? Is there "a proper level" of MPS and how do you determine/test for the level?

MPS is an oxidizer and will oxidize any bather waste (amonia, urea). Chlorine is an oxidizer and sanitizer. I think I read somewhere in this forum that 90% of chlorine demand is due to oxidation. So, a moderate level of MPS will allow lower levels of chlorine. Regarding the proper level of MPS, the Nature2 User Manual specifies this. According to chem geek, "To get rid of bather waste (ammonia/urea in sweat/urine), the rough rule of thumb is that it takes 3-1/2 teaspoons of Dichlor or 5 fluid ounces of 6% unscented bleach or 7 teaspoons of non-chlorine shock (MPS) for every person-hour of soaking.". I have found I need less than these amounts, probably due to the Nature2 cartridge and ozonator. I use Nature2's MPS test strips (LOW/OK/HIGH) to test my MPS level.

Lastly, do you think the Nature2 silver nitrate cartridge makes a real difference in lowering chlorine use?

Yes, it can. If you use Nature2's low chlorine recipe, routine chlorine usage is zero. As I stated in an earlier post, I maintain a FC level of 0.5-2.0 ppm by adding a squirt of bleach after each soak.

[simonc]

Mike (mcw53) -

Thanks for the information about Nature2 and MPS. I have decided not to use the Nature2 (silver nitrate) system for now. Here's my plan ...

1. I've drained my tub and added new water and adjusted levels.

2. I've ordered a good test kit - Taylor K2006.

3. I'm going to try the diclor-then-bleach method recommended by Chem Geek & Nitro.

I'll consider the Nature2 cartridge as an option for the future.

I would like to get some feedback from people who have used the silver nitrate cartridge. I recently posted a question on this forum asking people to share their experience with the system. No one responded. However, it seems that you are happy with Nature2.

Thanks,

- Simon

[mcw53]

You'll be happy with the dichlor-then-bleach method. It should definitely help keep your water "managable" for a longer period of time. The K-2006 kit is good and is what I use also. Don't bother testing for CYA until your calculated CYA is at least 30 ppm. The kit is not designed to detect levels below 30 ppm and you'll be wasting your CYA reagent, at 7 mL a pop. I used The Pool Calculator to determine how much dichlor was equivalent to 40 ppm FC (36 ppm CYA). I tested for CYA after adding that amount of dichlor. The test measured ~30 ppm CYA and I then switched to bleach.

You can add the N2 cartridge at any time if you choose to. I was originally attracted to N2 because of the low chlorine recipe, but have since switched to a mix of MPS and chlorine. Turns out that chlorine isn't as bad as my preconceived notions. Anyway, I am happy with N2 and have no thoughts of discontinuing using it. I like the idea of natural sanitation and the fact that I can take off for a week without worrying about bacteria infesting my spa. They are good for 4 months and you can get them online for about 20 bucks.