Your test results look very good. I might suggest more CYA than you are planning. Use the bleachcalc but about 6 more lbs should get you about a 25ppm increase up to 40....that's the level I would shoot for.
Black algae is a tough customer. I have no experience with it but I believe the common method is constant high levels of chlorine and brushing as many times daily as you can. Others with more experience can help more.
Bookmarks