chem geek
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Posts posted by chem geek
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Just remove the foam by scooping it out. It will eventually dissipate. You can drain/refill if you want -- up to you. It's the thickeners in the splashless bleach that cause the foaming.
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You need to understand that the active chlorine (hypochlorious acid) level is proportional to the FC/CYA ratio so your cover will have no problem with an FC higher than 5 ppm when the CYA is as high as your 260 ppm. Even 10 ppm FC with 260 ppm CYA is the same as only 2 ppm FC with 50 ppm CYA in terms of the active chlorine level which is what reacts with the pool cover (and your skin and hair, kills bacteria, prevents algae, etc.).
Unless one of your algae nutrient (phosphate, nitrate) levels is quite low, you could get algae growth at the low FC/CYA ratio. This may not show up at first as visible algae but may be a higher-than-normal chlorine demand as chlorine tries to kill algae faster than it can grow. Then, again instead of visible algae, the water may turn dull/cloudy before it the algae clumps enough to look green. Different algae behave differently in their growth, but green algae often develops in this high chlorine demand --> dull/cloudy water --> green algae bloom sequence.
The BioActive product is very hit-and-miss, mostly a miss. It's very hard to control the bacteria growth (with its enzymes) especially when chlorine is present.
I suggest you keep your FC higher to keep the FC/CYA ratio reasonable (above the level where you notice unusual chlorine demand or water not crystal clear) and over time dilute your water to get the CYA lower. I presume you may get winter rains in your area so should definitely use those to help dilute the water.
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Why don't you buy a Taylor K-2006 test kit and do the testing yourself to be sure? The first place probably has more accurate results, but it also depends on the care of the person who is doing the test.
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1 cup of 8.25% bleach in 400 gallons would be 13.5 ppm FC or over 30 ppm bromine so it's possible this is high enough to bleach out your bromine test, depending on what sort of test you used. Try diluting your spa sample by 1 to 5 with distilled or filtered water (without chlorine or bromine in it) and see if you get a reading.
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The active chlorine (hypochlorous acid) level is proportional to the FC/CYA ratio. This is because CYA is a hypochlorous acid buffer. So if the FC/CYA ratio is lower then there is a lower hypochlorous acid concentration so slower chlorine reactions.
If you had no CYA at all then the hypochorous acid level would be much higher and therefore much faster. It will be limited from hypochlorite sources by the pH rise, but it will still be much higher than with no CYA. So high that if kept longer-term it would damage spa components such as degrading hot tub covers faster. This is one reason the industry says never to use bleach. That's simpler than having to explain the full reason which is not to use only bleach and instead make sure there is some CYA in the water.
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Yes, your numbers are lower than the 10% I assumed so would be proportionately slower -- figure twice as long.
MPS oxidizes bromide to bromine the most slowly (ozone is in between in its speed). I don't have actual rate numbers for MPS but was told by Dupont that it is slow which is why MPS in a bromine spa will tend to have the MPS oxidize bather waste first.
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The paper in this link gives the rate of reaction of chlorine oxidizing bromide to bromine. It looks like it's roughly a conversion of 4% of the bromide every minute when the FC/CYA ratio is 10%, but that's at cooler temperatures (i.e. 77ºF). At 95ºC it would likely be about double the rate plus the HOCl concentration is nearly triple so net that's 24% per minute. So figure the conversion is mostly done within 10 minutes.
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Since the foaming also occurs with outdoor tap water from the well, is your well water treated with any chemical? Perhaps a disinfectant was used that causes foaming. Something along the lines of a linear quat, but probably not that specifically.
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Yes, chlorine oxidizes bromide to bromine rather quickly. Ozone does it more slowly and MPS even more slowly.
MPS is net acidic, more so than even Dichlor.
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I also assume that when you used BBB or Nitro's method that for chlorine you initially used Dichlor to build up some CYA and then switched to using bleach though once a month would use Dichlor for a day. Most people doing that find their spa water lasts at least double the time compared to Dichlor-only. Also, since you seem to have more trouble than most, you may be introducing more chemicals into the spa that need to get oxidized -- perhaps you aren't going in as clean as others and may have more oils or lotions that build up faster. Or it could just be that you have more chemical sensitivity so require less chemical buildup than most. Chlorine won't oxidize or eliminate every chemical though does do a better job than bromine or non-chlorine shock (MPS).
As for bacteria, if you always maintained the proper chlorine level in the spa then there shouldn't have been any bacteria, especially assuming you used Ahh-Some just before a water change to remove any biofilm.
As for MPS, some people are sensitive to it. It's not really the MPS itself that is an irritant but the minor by-product in it potassium persulfate (not monopersulfate). People using the Nature2 system with MPS don't have a problem with this because the silver ions react with persulfate to eliminate it and produce sulfate radicals and divalent silver ions (see this link for the reference on this).
Another way to remove chemicals from water would be coagulation/filtration, but if the enzyme approach is working for you then that's fine.
I would definitely like to speak to Cal regarding their enzymes and urea particularly in the cooler water found in pools. Urea is the largest nitrogenous component of sweat and urine and is normally fairly slow to oxidize from chlorine so it builds up. In spas, the hotter temperatures may handle it OK, but not so much in pools. If enzymes can be used to help oxidize urea, then that's a plus especially in higher bather-load pools (e.g. commercial/public) since chlorine oxidation of urea tends to produce nitrogen trichloride that is volatile and irritating. Most enzymes do a decent job increasing oxidation rates for a variety of organic chemicals but they tend not to handle urea (there is an enzyme "urease" that is found in bacteria and requires nickel or other heavy metals to be activated, but I haven't seen any enzyme products using it or any alternative to get rid of urea).
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The key is not to use bleach alone since that will have too high an active chlorine (hypochlorous acid) level. The idea is to build up the Cyanuric Acid (CYA) level first, most easily done by using Dichlor initially before switching to bleach. With CYA in the water, chlorine's strength is significantly moderated so will not harm spa components.
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Do you not have an ozonator? It sounds like you build up slow-to-oxidize organics in your spa possibly from heavy bather load with no ozonator. In that case supplemental oxidation can be helpful. Enzymes are one way of achieving that by allowing oxidizers such as dissolved oxygen to oxidize the bather waste more readily.
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Ahh-Some is better than Spa Flush.
You need to maintain disinfectant (e.g. chlorine or bromine) in the spa at all times. Bacteria can double in population every 15-60 minutes.
You need to add enough oxidizer after your soak and still have a disinfectant residual through the time of the start of your next soak.
It sounds like you may have relied on MPS too much and let bromine get to zero. That was the main mistake.
Green usually means copper. Are you using a copper ion product of some sort -- products with "Blue" in the name? -- or using "mineral sticks" that may have copper in them?
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There are only a small number of chemicals that get oxidized by MPS and not by chlorine. Many people use chlorine alone with no problems. You can certainly use MPS if you want to and it is net acidic so can help bring down pH or maintain it, but it's up to you. It's not necessary, but not harmful either.
Even users of Nature2 with MPS find that they usually need to use chlorine on occasion to keep the water clear, particularly if they do not have an ozonator.
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Total Bromine will measure as Free Chlorine in a DPD or FAS-DPD type of test. The reason is that monobromamine (i.e. inorganic combined bromine) is in equilibrium with monobromammonium ion that may release a positively charged bromine ion that reacts with DPD. Since this is also how this combined bromine is still effective as a disinfectant, it is not necessary to measure true Free Bromine and there isn't an easy way to do that anyway.
The factor of 2.25 applies to any chlorine reading to convert to the corresponding bromine reading though as I wrote you can convert from Free Chlorine to Total Bromine using this factor (a factor of 2 is approximate and reasonable).
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Enzymes alone usually won't foam, but it's possible the product has some surfactants that may foam. You normally should not need to use enzymes if you are dosing with sufficient amounts of chlorine. To avoid foaming, avoid getting soap into the spa -- thoroughly rinse any swimsuits you wear in the spa.
If you do get foaming, skim it away from the surface. You can also use a scum ball which will remove surface organics including oils and soap film.
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By the way, calcium stearate is also one of the main components of soap scum; magnesium stearate is another common component of soap scum. When hard water (calcium and magnesium) combine with soap (sodium stearate) it produces soap scum.
Calcium stearate is found in some lubricants but I'm surprised there's enough of it to have as much continual flaking as you are seeing.
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Saltwater chlorine generators are generally designed to have enough output to provide a background level of chlorine but are not usually enough to handle heavier bather loads. Some have a "shock" feature that keeps them on longer, but even that may not be enough. You may need to add an oxidizer after your soak -- either chlorine or non-chlorine shock -- and let the saltwater chlorine generator take care of maintaining chlorine between soaks. If you had an ozonator, that would hep oxidize the bather waste though still may not be enough and it would deplete chlorine shortening the life of the chlorine generator as it would need to output more to keep up.
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You may have sensitivity to halogens in general so both chlorine and bromine. If you think it's only chlorine, then you can try oxidizing your bromide to bromine by using another non-chlorine oxidizer such as non-chlorine shock (MPS) though some people have sensitivity specifically to it.
If you had a sufficient bromide bank and you waited a bit after adding chlorine before entering the spa, then it's unlikely there was any chlorine left when you went in because chlorine converts bromide to bromine rather quickly and the chlorine gets consumed (it becomes chloride salt).
As for Dichlor, it produces chlorine though the Cyanuric Acid (CYA) with it will moderates chlorine strength. As for a salt water system, it just generates chlorine or bromine depending on the salt in your spa.
The only residual chemical specific to Clorox bleach is sodium polyacrylate. So it's more likely to be a reaction to halogens, both chlorine and bromine. Your doctor could do a patch test to be more definitive.
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Your used Jacuzzi may have biofilm, greases and oils in it consuming oxidizer (bromine). I suggest you get Ahh-Some to do a thorough cleaning.
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If you removed the jets, you can disinfect them with anything so long as you rinse them thoroughly before and after disinfection. You just don't want chlorine and biguanide to mix, but rinsing the removed jets with water should work.
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I suggest you use 50 ppm Borates for additional pH buffering. There is probably a lot of aeration on this spa AND I'll bet there is undissolved chlorine gas outgassing from the saltwater chlorine generator. If you can somehow direct the bubbles from that generator downward so they have a longer chance to dissolve (the chlorine bubbles will dissolve, the hydrogen gas bubbles will not) then that could help. The additional pH buffering won't lower the amount of acid you need, but it will slow down the rate of pH rise to help keep the pH in check. Keep the TA low -- not above 50 ppm.
As for chlorine loss, that is not related to the higher pH unless the spa is exposed to sunlight in which case hypochlorite ion does degrade from the UV in sunlight much faster than hypochlorous acid. Also, it sounds like you might not be using any Cyanuric Acid (CYA) in the spa. Since this is at a hotel, so a commercial spa, you may not be allowed from regs to use CYA, but if they don't prevent it then I suggest targeting 20-30 ppm which will help reduce chlorine loss from outgassing. You can then target a higher FC level to compensate -- say 4-6 ppm FC (i.e. 20% of the CYA level) which should be plenty of disinfection/oxidation even for a commercial spa.
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You don't need a bromide bank when using tabs TO MAINTAIN A BACKGROUND LEVEL, but you definitely need it at first if you want to shock to raise the bromine level quickly. Over time, the spent bromine from the bromine tabs will build up a bromide bank BUT ozone oxidizes some bromine to bromate so there is a battle going on between the bromine tabs adding bromine going to bromide and the ozonator both creating bromine from bromide AND turning some bromine into bromate where it remains as such. So as for what goes on with your bromide bank is unclear -- who wins out, the ozonator creating bromate or the bromine tabs adding more bromide from spent bromine. Unfortunately, there's no easy test for testing bromide explicitly.
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The high CYA will not affect the bromine. Only chlorine significantly bonds to CYA.
Palin vs Taylor
in Swimming Pool Water Chemistry
Posted
I have compared the Taylor K-2006 pH against an Oakton pH 5+ meter I calibrated with 3 standard solutions and I can tell you that the Taylor is absolutely accurate.
The problem may be that you have higher chlorine levels and the Palin pH test might not have appropriate chlorine neutralizers in it. If you add sodium thiosulfate drops to try and neutralize the chlorine, then that solution itself and the reactions with chlorine can lead to higher pH. Taylor has a special proprietary blend of chlorine neutralizers in their pH reagent so up to around 10 ppm FC their pH will still be accurate.
As for the FC test, you should use the Taylor K-2006 or similar test kit that has a FAS-DPD test since that is by far the most accurate for chlorine testing. Here again I have tested numerous solutions of chlorine that I standardized and the Taylor always came out very, very accurately -- within the 0.2 ppm resolution of their 25 ml sample size and about 5% of total FC value (Taylor claims 10%, but if you're careful you can usually get to within 5%).