Quote Originally Posted by BigDave View Post
I don't know what that is, do you? I don't put anything unknown into my family's pool.

Fresh bleach or not, to shock a pool with 60ppm CYA the FC must be kept above 20 until it loses less than 1ppm FC overnight and CC <= 0.5ppm.

Mustard algae is often greenish yellow to brownish yellow and it seems to prefer the shaded side of the pool and aggregate in seams and small pits in floor. It often disperses easily with a brush or even a wipe of a hand. Mustard algae takes much higher FC levels to kill.

Do you think maybe it's just dirt that's too fine for your filter or never gets in the filter? Did the trouble start after a period of heavy usage - July 4 pool party?
I need to take a photo... I will try if it returns... I have a water proof camera and I just thought of that.

But I can describe it... It is mostly green, and it is thin wispy following the bottom pattern of my pool. (LOL) My pool liner is not wrinkled but it's imperfect due to what's underneath. I put it on solid ground, no sand.

The safe MA I refer to is what they call SAFE muriatic acid. It's supposedly more safe than regular MA and does not smoke when poured into the pool. Does that help? Ace Hardware sells it.

When I brush I see small clouds of green, and again I say we are not talking a lot of algae. I am certain it's algae and not sediment as I am really good about vacuuming. I usually get in and create a whirlpool and suck up all the debris with the hose as it's easier.