Your TA is a little bit high, but in a vinyl pool, is actually okay where it is, for now....the green water should be much higher on the priority list!

The CYA is a very subjective test, and because it relies on turbidity for results, an algae outbreak can definitely affect the reading. So can reading the test without letting the sample sit for a few minutes after mixing with the reagent. So can reading the test in dimmer lighting than the previous time. See what I mean? So....the best you can do right now is base your shocking on the higher CYA level, and then test for CYA again after you get the pool cleared up. The key is going to be getting that chlorine up to 25 and keeping it at that level until the algae dies off. You'll know you're getting there when your water goes to blue-cloudy, which will be the dead algae that needs to be filtered out.

As I said in my above post, I definitely wouldn't use any more stabilized chlorine in this pool. You didn't list a hardness reading--too little hardness in a vinyl pool is irrelevant, but if you really want to continue to used powdered chlorine, then you may be able to switch to cal-hypo granules for a little while, depending on your current CH level. YOu can't let it get too high, though, especially with TA and pH on the higher side because it can contribute to cloudy water. I would just use bleach, personally--it gets the chlorine in the pool, and doesn't add anything else that you have to watch out for!

Janet

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