Where'd the CYA go?

[usmarinemike]

I've moved to a house with a marginally well taken care of pool, and it's my first pool so I've been getting it and myself up to speed over the past few weeks. I think it must have been covered up right after hurricane Irene last year. I left it covered and opened it up several weeks ago to see it coated in green and all kinds of interesting crud lying on the bottom. It's all vacuumed out (finally) and I brush it every day. I have a few problems (it's green) but this post is only going to focus on one of them. I have also come to despise pool stores (Don't tell me there's no way I can truly understand all of these chemicals and tests (simply because you don't)). Anyway, that's another story. So I take my water a few weeks ago and my CYA is 20ppm. Low. Fine. I forgo buying the 3# for $25 of pool store stabilizer and go get the Aquachem for $12. Afterall, it's labeled 100% CYA so how messed up can it be? Add about 2.5# using a boot sock tied to the inside of my skimmer pot. I took more water in to the pool store about a week later and they still say the CYA is 20ppm.

What gives? Poor testing? Something metabolizing my CYA? Poor product? It was tested by the same person on the same machine.

17,500g 27' AG round Hayward Powerflow LX with Hayward Dreamline sand filter and I'm just about to pull the trigger on a legitimate test kit.

[Watermom]

If the original 20 was right, then you should have about 40ppm of CYA in there now. Don't add any more at this point until you do what you know you need to do -----pull the trigger and get the good kit! (You can get the Taylor K-2006 or2006C through the testkit link in my signature below.) Then, you will no longer have to rely on anybody other than yourself to test your water and you will know what your readings actually are.

Welcome to the Pool Forum!

[usmarinemike]

Another question (don't have other posting privileges yet). I'm working on getting rid of the green. Regardless of CYA level, should I keep dumping the Cl in throughout the day to keep it at shock level or just morning and night?

[aylad]

The chlorine that you put in in the evening is working more efficiently than what's put in during the day, because the sun is helping consume the daytime additions....but that being said, the more consistent you are about keeping it at shock level, the quicker the algae will die. If you are home and able, then by all means add Cl during the day, too....but if you're not home, then morning and evening will also work, it may just take a little longer.

[PoolDoc]

Don't add CYA, till the pool is no longer green -- algal biofims can incorporate bacteria that metabolize CYA to ammonia or worse. Since you have some CYA, go ahead and add plain 6% household bleach at the rate of 3 gallons per dose till you read the "orange" level on an OTO (yellow drops) kit. Hold your chlorine level there until you get a K2006, and can accurately test both chlorine and CYA levels.

Check your pH BEFORE the chlorine gets that high and adjust it to between 7.0 and 8.0. Use 20 Mule Team borax to raise; muriatic acid (see page link in my signature) to lower.

Put your sand filter on recirculate -- it won't filter that stuff and we're beginning to think those undersized over-driven AG sand filters actually fragment algal particles into an even finer and harder-to-filter slurry.

Read the test kit, muriatic acid, and Best Guess pages in my signature -- they all apply.

Just curious -- nothing to do with pools -- are you at Lejeune?

[usmarinemike]

OK. That's pretty much what I've begun doing. If the FC gets below the top level of the OTO test I use poolcalculator to figure out how much to take it back up to shock with the BGC. I have a giant bucket of 73% cal-hypo that I've been using to keep the level up that I bought before I became disgusted with the pool store. It was a long time coming, and she looked me straight in the face and told me that sodium bicarbonate and sodium hydrogen carbonate were not the same thing. She also told me that I couldn't test things myself. I had to use her machine. Our relationship was over even before I found your site.

I agree on the sand filter. I knew I was in trouble when I saw that the pump was rated at 70gpm, and the max rating for my filter was around 55. It says it right on the side in big numbers. Who comes up with this crap? Could this be the reason that although my water is green, it's not swampy and I can see all the way through it? My algae is just really fine?

[PoolDoc]

Who comes up with this crap?

The same sort of people that sell Lipitor instead of generic statins that work better for 1/4 the cost. I'm guessing you can think of a few similar examples that made it through the US Navy or Marine Corps supply chain. Deception, deliberate product ignorance, and outright lying are fundamental qualities of marketing in US society. The only thing unique about what's happening in the pool industry, is that I know enough about pools and pool chemicals to recognize most of it. With medical products or consumer goods, I can only recognize a little bit of it.

Could this be the reason that although my water is green, it's not swampy and I can see all the way through it? My algae is just really fine?

If it was green WITHOUT algae, it would probably be iron at low pH. But, green with algae on the sides, is probably still algae. If you've got a white five gallon bucket, you can test and see:

1. Fill a CLEAN white 5 gallon bucket to pool water, to within 6" of the top.
2. Add 1/2 cup of baking soda, and mix.
3. Add 2 cups of 6% bleach, and mix.
4. Cover and wait 24 hours
5. If you have brown or khaki sediment, it was algae. Red-brown or orange sediment, it was iron. Something else - tell us about it.