Water Chemistry, Nj

[Dnice]

Someone please assist me and set me straight. I had my water tested, and the results were: TA=120, pH=7.6, CA=100, TH=280, TC=4 and FC=4.

According to pool store, the TC and FC are high. Should I be alarmed? I haven't used the pool too much so far this year, so maybe it will go down with some swimming? Will it hurt people?

Also, it seems like the TA, pH, and CA are at the high end of normal. In other words, a few more points and they too would be a deemed high. Should I be worried about any of these?

I would appreciate anyone's assistance. Thanks.

[PaulR]

Is CA calcium (more commonly abbreviated CH) or cyanuric acid (more commonly abbreviated CYA)? If it's calcium it's no problem, actually 100 is pretty low. If it's cyanuric acid (stabilizer) then it is high, and really the only way to reduce it is to drain out some water and refill.

FC 4 won't hurt anyone. If your CYA is 100 then it's not doing much good either, though; see the Chlorine/CYA chart in Pool School.

What kind of chlorine are you using? If it's dichlor (sodium dichloro-yadayada) or trichlor (sodium trichloro-yadayada) then your CYA probably is very high and needs to be fixed.

TA is higher than the usual recommendation but really what matters is whether your pH is stable. If pH is constantly rising, then lowering TA will help that. If it's stable, then the TA is fine.

Finally, if you want to be in control of your pool you need to do your own testing. Pool store results can vary widely because different people do it each time and they have different levels of training and attention to detail. When you do it yourself the test results will be more consistent and useful.

--paulr

[Dnice]

Thanks PaulR! Yes, CA is really Cyanuric Acid, CYA. I assume I would not have to drain the whole pool, but just how much? 10-25%?

[PaulR]

Well, if your CYA is 100, and you want it to be 60, you need to replace 40%. If you live in a really sunny place then some people like it a little higher, like 70. If you have a sand or DE filter, you'll lose and replace some water over time due to backwashing, so the CYA should (very) slowly go down that way; I still think you should replace a chunk of water up front.

But you have to stop using dichlor or trichlor as your chlorine source. Bleach or liquid chlorine (they're the same stuff just different strengths) will add nothing to your water except chlorine, and a teeny amount of salt not enough to worry about.

--paulr

[imnay]

Well, if your CYA is 100, and you want it to be 60, you need to replace 40%. If you live in a really sunny place then some people like it a little higher, like 70. If you have a sand or DE filter, you'll lose and replace some water over time due to backwashing, so the CYA should (very) slowly go down that way; I still think you should replace a chunk of water up front.

But you have to stop using dichlor or trichlor as your chlorine source. Bleach or liquid chlorine (they're the same stuff just different strengths) will add nothing to your water except chlorine, and a teeny amount of salt not enough to worry about.

--paulr

Okay - I get into threads like this and get told off often by those that always know better. All I can share our personal experience of over 20 YEARS of having perfectly clear and fine water for swimming across all of those years.

We self test our water often. We only ever use a simple 4-way test kit.

We keep our PH where it should be and we keep our Alkalinity where it should be. We have an in-line chlorinator and we have used tri-chlor stabilized three inch tabs for all the years and have never had a problem - ever. If chlorine appears bound which we have always understood to mean too much stabilizer we use liquid chlorine to shock away the problem and it always very simply shocks away.

We use a good two week rated algaecide and we NEVER have algae.

Maybge there is actually a good reason to get more complicated with your water testing and I don't want to argue chemistry with Subject Matter Experts BUT we continue to use the testing and procedures given to us by our installing pool contractor and they have been simple rules to follow and have ALWAYS worked - as in always worked.

Or course if you care to test for Total Chlorine and Free Chlorine and add only non-stabilized liquid chlorine or grocery store bleach and then try to be a chemist and carefully add stabilizer (cyanuric acid) please choose that method - I am not saying that is wrong but that there is a more simple way - how do I know - cause the 22k gallons in our pool @ 94 degress is perfect. We are simple people and began pool maintenance back in 1986 where there was no internet access to forums like this and the SMEs that post on them and all I can share in good fellowship and personal experience is simple 4-way test kits WORK and the off the shelf pool products you can buy at your corner hardware store work just fine so use the KISS (keep it simple, stupid) method or make it as complicated as you care to all I am trying to share is maintaining pool water is not rocket science and the fewer steps you must use to have crystal clear water to me is better than more steps that accomplish the same thing.

Tri-chlor tabs work just fine - if they didn't they wouldn't sell so many.

A good algaecide will keep you from having any algae.

A 50 lb bag of Sodium Bicarbonate @ $ 19.95 will work great to increase Alkalinity instead of way too expensive "Alkalinity Plus".

A 50 lb bag of Soda Ash @ $19.95 will work great to increase PH instead of PH Plus in a spiffy plastic 4 lb container for $ 8.00.

Liquid chlorine - in our experience - is a very cost effective shock though we don't have to shock often.

The above is all you need to have crystal clear water that is not only safe to swim in but probably okay to serve at the table. We know this is true cause it has been for over 20 years. Other ways are fine too. We aren't arguing with anyone - just offering a different opinion.

Sorry for rattling on so long - You can pick your path to good pool water - just know that there's more than one way to get there and some are easier than others - LOL but it's true!! Cathy and I are not chemists - just happy pool owners having great water for over 20 years - probably more years than some have been old enought to own a pool.

Good Luck whatever you choose to do!!

Jim

[chem geek]

Jim,

You are getting closer at providing more details about your pool as I list in this post, but you failed to mention the shocking to clear cloudy water in your pool every 4-6 weeks and the fact that your algaecide is copper-based and that your pool is vinyl (so less likely to show any metal, copper, staining) and that you get rain overflow so more dilution of water, etc.

Yes, an awful lot of Trichlor gets sold and there's also an awful lot of people reporting algae problems with their pools (this includes SWG pools where people have 1-2 ppm FC with 60-80 ppm CYA and get algae growth). An algaecide will help prevent such problems if the algaecide (or phosphate remover) is used regularly, up to a point. However, CYA doesn't go away so if you don't have water dilution (or bacteria converting CYA into ammonia if you let the FC get to zero), then continued use of Trichlor will continue to build up CYA. It's not just algae that would then become an issue, but the chlorine won't oxidize bather waste (and suntan lotion, etc.) as quickly leading to cloudy water. Shocking will help for a time, but after a while even that won't be enough. So then one could buy enzymes, etc., but why not just manage the CYA level in the first place?

Some pools can be reasonably managed using Trichlor pucks, but those with less water dilution cannot, at least not in the long run -- such as those with cartridge filters, larger pools, pool covers, no rain overflow.

Richard