How long should it take to clear black algae

[joecus]

Sorry, I wrote the wrong computation, I am multiplying by 7 and getting 14. Normally I take 3 parts water and multiply by 4. Today I did 6-1 and used a calculator and messed it up, So My number is 14, not 33. I will raise it up to at least 20 for the next three days and see what happens.

[Watermom]

OK. Try and sustain that high reading without letting it fall. I know that is not totally possible, but the more often you can add bleach and get back up to 20, the better.