my tank about 5 months old now, nitrates and phosphates are pretty much non existent .. Im running eco bak plus bio pellets and just recently starting to get cyano just on the sand . I have 2j ebao r'8s , , same lighting cycle , same amount of fish . I was target feeding with some coral frenzy and dosing acropower like every 4 days so I wasn't sure if that was causing it or not . Since then I stopped feeding and dosing and im still getting it to come back but strictly on the sand. Corals and everythin as happy as can be. I Read that sometimes you need a diverse amount of bacteria so I tried zeobak in hopes it would help the situation, I only have dosed that twice and it doesn't seem to be helping . Trying to avoid chemicals at all costs and a blackout if it all possible... any thoughts??