Algae

[silverfish]

I have a 55 gallon saltwater tank that I have had for ten years. The
live rock have been in for ten years. I have h/o lights. Protein skimmer
and a sump. I developed a algae that looks like brown cotton candy.
I am using r/o water. I removed the few coral and fish I had in the tank
and moved them to a smaller tank which is doing fine. I checked the
nitrates, nitrites and amonia levels and they are where they should be.
I turned off the lights and the algae went away. I turned the lights back
on for 7 hours a day and the algae is back. I do have an assortment of
crabs and snails in the tank. Any suggestions?

 

[SquishyFish]

Isnt it cyano that reacts to the light like this. I maybe off on this one, but that sounds right. Mabye someone can clear it up.

Another possibility is "light shock." Just like you can bleach corals when you upgrade from p/c lighting to m/h unless you acclimate the tank to it, you may have starved the bad algae then fed it a huge meal (so to speak). No light for several days...then straight back up to 7hrs a day.

Also..what kind of bulbs do you use? Im assuming h/o was suppose to be N/O lighting. It sounds like you have been around long enough to know not to use shop lights because of the spectrum problems.

Have you considered putting a fuge on the tank to suck up the excess nutrients in the tank?

The one parameter you didnt mention was PO4.

Sorry for all the different options..just trying to cover all the possibilities.

Squishy

 

[steve-s]

Sounds like you have a case of excess dinoflagellates aka "snot algae".... That link should help if it is, maintaining a constatnt slightly elevated ph is key in defeting it.

Cheers
Steve