1 gal of 10% every 2 days?

[Watermom]

Test in the evening when the sun is off the pool and then again in the morning before the sun is on the pool. If you are losing more than 1ppm overnight, then you are fighting something in the water and need to take the cl level up to shock level and try and keep it there until there is no more overnight loss greater than 1ppm.

[CarlD]

I agree with Watermom.

Also, your TA is very high as well. That is, in part, a function of how high your pH is, and, if you test TA when the pH is (briefly) in the right range, you'll see it's lower, but still too high.

What you need to do is get your TA 'way down, which means adding a LOT of Muriatic Acid. I'm guessing you have a shotcrete/gunite/plaster pool (as opposed to vinyl or fiberglass). This allows you lower your pH safely to levels in the high 6's without danger of harming the surface. I'm not sure how much acid you need, but you can figure that out easily. Your waterfall will aerate it back up. But you should aim for the low end of TA--probably 80 at the highest. This should help keep pH down.

I strongly suggest you consider the 50ppm level for borates in your pool as well. With the lower TA, a borate level of 50ppm, you should have the dual effect of controlling your pH better and fighting off algae better. It seems to really help pools with your problem. This will use a lot of both borax and Muriatic Acid, and you have to get your FC under control as well.

Since you are still swimming, I'm guessing you are in the more Southern regions. Therefore you should consider raising you CYA to a level of at least 50ppm and trying to maintain FC there. Even up here in NJ, I frequently raise my CYA to the 40-50 level because of UV chlorine loss. And aylad, my fellow Mod, keeps hers in the 70-80 range in Louisiana because otherwise she faces what you face, with FC.

But you gotta get that pH down because with pH that high, the chlorine is far less effective, as well.

[waterbear]

you should consider raising you CYA to a level of at least 50ppm and trying to maintain FC there.

Exactly my first thought.

[CarlD]

See? I DO have good ideas once in a while!

[aylad]

In my climate, with a CYA of 30, a gallon of 10% every 2 days is very believeable. That's why I keep mine higher--I like to keep it at 80-90 for that very reason. With my current CYA at 90, I'm using about a gallon of 6% twice weekly and keeping my FC at 8-10. I go through a LOT less chlorine that way!

Janet

[CarlD]

What progress have you made? Has the advice we offered been any help? Good luck!