First time pool owner - CYA Loss

[Asuli]

Hey everyone,

I just moved into my house with a pool the beginning of March and since Leslie's pool supply is nearby I use them to test the water and the BBB to balance the pool chemistry. The pool had been neglected since the house foreclosed a year ago so I hired a cleaner who emptied it out, cleaned it up, then refilled it.

Of course now I know I should of vacuumed it out and balanced it instead, then used the saved money to buy a TF-100 but live and learn I guess. The problem I'm having is with the cyanuric acid levels. When I refilled the pool I brought the CYA to 50, kept the CL at around 2 by adding ~ 1/2 gal 6% bleach per day, and CH to 27. I admit I haven't tested it within the past week and a half but noticed after adding the usual chemicals the pool took on a greenish tint.

I had Leslies test the water and came out with these results: 0 FAC, o TAC, PH 8.0, TA 120, CH 270, CYA 0, TDS 550, Phosphates 0. I'm worried about the dramatic cyanuric acid loss since I was under the impression that once added it stays the same unless diluted or splashed out. I've only swam in the pool three times and use a cartridge filter so no backwash loss could occur.

Any suggestions on what to do and how to prevent loss in the future. By the way, I do plan on purchasing a liquidator and TF-100 as soon as I have some extra funds, perhaps even when that $300 rebate check comes in.

 

[duraleigh]

If you put 50ppm CYA in there and there's nothing you've done to remove it, it's still there.

I suspect you have some testing errors.

BTW, I hope you are still putting chlorine in your pool. If not, you need some.

pH is too high, muriatic acid will lower it.

 

[JasonLion]

On the CYA I would assume testing error at Leslie's. Do you at least have a basic test kit that measures chlorine and PH? You need to check and adjust the chlorine and PH levels once a day and that is almost impossible without some kind of test kit.

 

[Asuli]

Yep, I have a very basic taylor kit at the moment and I have been taking measurements every morning and night this week. The chlorine is always at 0 FC and TC at the end of the day and was at 5 FC this morning (~5 am). How much rain would it take to dilute 50 CYA? I think it's only drizzled three times in the past two months.

 

[JasonLion]

To get CYA down from 50 to near zero would take something like a 90% water replacement. That doesn't seem at all likely unless you have a leak and an autofill system. Perhaps the earlier test where it showed 50 ppm was wrong? How did you bring the CYA level up to 50 originally?

FC vanishing when it is sunny will happen with CYA is zero, but it can also happen if you have algae. Low levels of algae aren't always visible right away, so we need more evidence to be sure which it is.

 

[Asuli]

I added a full 8lb stabilizer bucket from leslies after dissolving it bit by bit in warm water. I did notice that not all of it was dissolved when I would pour it slowly over the return. Out of curiousity, if it is algie growth will I only lose the FC during the day or should it be a consistent loss?

 

[JohnT]

CYA is very slow to dissolve. Some people report it takes nearly a week.

Algae will consume chlorine day and night. Accelerated loss during the day is due to sunlight.

 

[Asuli]

Thanks everyone. I'm beginning to think the CYA test was wrong since the chlorine held today for the first time after I shocked the pool last night. Guess it's time to have it rechecked and to order that TF-100. Why is it that sometimes CYA levels 20 or below don't always register?

 

[JasonLion]

Turbidity tests always have trouble reading low levels. You would need to fill the test vial so high that it would use lots of reagent and be much more difficult to use.

 

[Asuli]

Well I feel much better now. I just went to warehouse pool supply for some cleaner parts that Leslies did not have in stock and of course had them run a water test. After shocking it last night, the tests show 5 FC, 5 TC, 0 CC, 8.2 PH, 75 TA, and 50 CYA. I'll run the pool calculator and fill it up with muriatic acid then fix the alkalinity. Apparently I did have some algie problems .