Okay, thought of one. If you have cyanobacteria, after taking the recommended preventative steps and siphoning off as much as you can, 250mg of erythromycin per 25 gallons of tank water, 2 treatments, 2 days apart, will cure your tank. No adverse affects on any sps, clams, lps, softies, fish, inverts, etc. that I have noticed in any treatments. And, the cheap way to do it is if you know a doctor (I use my dad), get a prescription if you have a prescription plan and save big money (it's just like Menards!). Can't beat $5 for enough erythromycin to treat over 600 gallons of saltwater several times over!