CYA still high after water change

[BarryY]

Well, I'm really frustrated. I was getting a lot of algae because ny CYA levels were so high I could not keep the chlorine levels high enough. So I drained the pool to about an inch below the bottom step (15,000 gal in ground, fiberglass). Refilled and CYA still tests way over 100!. Black dot dissapears about half way between zero and the 100 mark. What else can I do? I hate the thought of having to drain and refill again.

[CToon]

I feel your pain Barry. The reason I ever found this site was my HIGH cya and the problems it gave me. THe way I dealt with it was draining it until I got the cya down to 90 and bought Bens test kit so I could test the high cl needed.

I kicked myself more then once for listening to the clerk who sold me the stablized chlorine and the pucks to go along with it. But anyway...

I know its not really the solution you were hoping for , but my advice is drain some more to get it down and get a test kit that allows you to test cl at the needed range

If there is a silver lining , once you do get it under control , CL levels are pretty easy to maintain .. dont lose much to hot sun

[BarryY]

100 is the highest on the scale, but it takes the smallest amount of volume. In other words, adding more solution would result in a lower CYA reading, so halfway to the first graduation results in a reading way over 100.

[lagtime]

Barry, I had the same problem. Years of Dichlor left me with an initial CYA that sounds like yours, maybe 1/2" of water in test tube obscured the black dot. I bet it was close to 400 ppm. After the first drain it was still >100 ppm.

I ended up doing 2 drain & fills, removing ~75% of the water each time. My CYA is now between 50~60.

I'm fortunate in that I live in an area where the water table is very far underground so the pool popping out or the sides caving in ( it's 12000 gallon FB) isn't a big concern.

You have to drain & fill again.

[fcfrey]

Are you sure you are using your kit properly??!!

I have 2 different kits, 1 is part of a Taylor kit. Directions for that kit uses 7ml pool water and add another 7ml of 0013 reagent in a seperate tube----You shake and wait then add the mix slowly in the tube with the black dot on the bottom until the dot just disappears--then read the mark at the water level..100 is near the bottom. The more of the mix it takes for the dot to disappear --- the lower the CYA.

My second test kit uses a slide with a dot on it. Again equal quantities of pool water and 0013 reagent ---- mix with the slide, wait, and begin raising the slide till it just becomes visable and read the scale at the water line Not the slide bracket at the top.

If your CYA really is high --- use double the pool water compared to the reagent then double the reading for better accuracy.

Hope you are reading incorrectly and don't have to drain any more.

[BarryY]

fcfrey, my test kit is a Taylor like the first one you described. I loose the black dot entirely with about 1/2" of water, about halfway to the 100 mark.

[fcfrey]

WOW!!!

Do a Google search --- CYA Reducer ---- There is a product to do that but it is expensive ---- which is cheaper.

I really do not want to suggest it but a good dose of algae will lower the CYA also

[waterbear]

fcfrey, my test kit is a Taylor like the first one you described. I loose the black dot entirely with about 1/2" of water, about halfway to the 100 mark.

The test is not accurate above about 80 or 90 ppm so I would suggest diluting a sample of your pool water with an equal amount of distilled water and testing that. Multiply the results by 2. If it is still testing high then dilute with 2 parts distilled water and multiply by 3. This should give you some idea just how high your CYA is

I would also stay away from the CYA reducers...they are melamine, exactly the same thing you are testing your CYA with. Do you want your entire pool to turn that milky white color and have to vacumn it out? Besides at $50 to $60 a gallon,which will lower about 10000 gal 20 ppm CYA (in actual use) it is a VERY EXPENSIVE solution!

Since you have a fiberglass pool you will have to do multiple drains and refills no more than a foot below your skimmer!....Do about 3 of them and retest. Keep at it until you get your CYA down to about 50 ppm and NEVER use stabilized chlorine for routine sanitation again and you won't have this problem.

[BarryY]

Well, after my SECOND drain & refill (about 90%), I'm down to cya levels of around 80-100. Going to try to maintain it from there.

What about my calcium hardness in a fiberglass pool? The mfg recommends around 300. Right now its around 150. Is there any danger in increasing it to around 300?

[waterbear]

Depends on where you ALK is. If both are high you run the risk of cloudy water or scaling if the pH goes high. The general consensus is that calcium is not needed in a fiberglass pool but I have been finding some conflicting info with no hard data to back it up one way or the other.....Fiberglass is more prone to staining by metals and perhaps the higher calcium levels help prevent this. Don't really know. Mbar might have some input on this subject. Maybe she will see this thread and reply.