I'm a recent convert to the BBB method, having lost far too much money to the pool store. Water was finally replaced in March due to very high CYA. I think I have my water reasonably well balanced now but I think I have some black algae left over from before the refill. It's scattered around the pool in very small black spots that turn dark green if I scratch them.
I have been maintaining FC at about 8ppm and brushing periodically, however the plaster is really old and seems to be scratching off a little as I brush it (Stainless steel brush) so I don't want to brush too hard. Also the plaster is really rough so i think the algae can hide from the brush.
Is there anything else I can do to help kill it besides brushing and maintaining FC?
I have various chemicals left over from the previous owner and my pool store days (60% polyquat, black algaecide, copper algaecide, yellow out, phos free) but after reading TFP and pool school have been reluctant to use any of them.
So, since I have them anyway, would any of them help with the black algae or should I stick to bleach/brushing only? Is the black algaecide just a more concentrated version of copper algaecide or does it have something special that would help here, and if I use it what problems can it cause to my water balance, if any?
CYA 60 or 70
Daily FC drop is around 3 or 4 ppm. I am using the Taylor k2006 kit