Re: Cyanobacteria scourge
#2
Me too! I have a serious cyano problem in one of my tanks. I've tried manual removal, various remedies (Blue Exit, Boyd's Chemiclean, Ultralife), reduced lighting, total blackouts, increased flow and it just comes back. However, there is some evidence that it is caused by low nitrate. The tank in question has had a very low level of stock (5 2 inch fish in 180 litres) and thus very low nitrate. About a month ago another of my tanks sprang a leak so all the fish from there were added to the tank with cyano and I'm seeing higher levels of nitrate now so am hoping that after another extensive manual removal it won't return. I'll update this post after I've done that and waited a while to see if it comes back again.
If low nitrate is the issue in your case, then planting heavily and dosing ferts including nitrate for the plants may help. Or possibly using tap water instead of the bottled water if your tap has nitrate in it. I can't dose with nitrate as it's an unplanted tank (Tanganyikan cichlids).