Cyno I think

[bonniewoodruff]

I have a 90 gallon cube FOWLR tank that I have had running for about 1 1/2 years. I have a sump with filter pads, bio balls, protein skimmer,a refugium, and a phos ban reactor. In the tank I have live rock, 2 clarki clowns, 3 damsels, a coral beauty angel, and a blue hippo tang. My clean up crew is a serpent star, a sand sifting star, hermits, nassarius snails, 2 turbo snails, a emerald crab, a porcelain crab, and a cleaner shrimp. I do a 10-12 gallon water change weekly. I feed 1/2 cube frozen food ever other day. I have T5 Lights that the bulbs were changed 3 months ago.
I have been having an issue with cyno on my rocks and sand. I have been manually removing as best I can at every water change. I have tested and test show 0 nitrates and 0 phosphate. I am now learning that that is because the algae is consuming them. A few days ago I noticed what looks like air bubbles on top of the cyno.
I have had my lights off now for 36 hours straight and it looks alot better now. My concern is that is is going to come back as soon as I turn the lights back on. I usually run them for 8 hours per day. I can't figure out where the excess nutrients are coming from.

 

[pbrano97]

yea that's definitely cyano. i would take your water to a lfs to get re-tested. could be a faulty test

 

[bonniewoodruff]

Nitrates test at 0 that's what I can't figure out

 

[mike007]

I have also been dealing with this myself. I have tried everything and nothing has worked. I finally resorted to quit doing water changes every week,cut back on feeding. and reduced lighting period. What I found was I was dosing trace elements through dosing pump and when I was doing water changes the tank was not consuming all of this which caused excess nutrients. Also I would recommend increasing flow, rinsing your frozen food,and don't add anything to tank that will not be used up and create phosphates.