Brown Algae on the sand?

[Haelstrom]

I've had this redish brown algae looking stuff on my sand bed for a couple of months now. It pretty much disappears when the lights are off and comes back when the lights are on. But it seems to only be in the shaddy areas. Never out in the open on the sand bed. It is under the edge of rocks and under corals in the shadows.

 

 

 

 

[FlowerMama]

Dinoflagellates more than likely but if you have a friend with a microscope have them check it out. Dusty, right? Like you can rustle up the sand and it just falls back into place.

[ndrobey]

Vacuum it up. But if it is dinos, you've got a problem.

[amphipod]

Dinoflagellates more than likely but if you have a friend with a microscope have them check it out. Dusty, right? Like you can rustle up the sand and it just falls back into place.

 

that or if not dinoflagellates its probably cyanobacteria.

[FlowerMama]

Yep, I have both.

[dillct]

Look like diatoms to me...no big deal. I wouldn't do anything other than change out my di resin (if needed)...usually an indication silicates are getting through. If it were dinos you would definitely know as you'd have brown snot with bubbles everywhere.

[Steve973]

It also looks like diatoms to me. Dinoflagellates are fuzzy and slimy and they develop floating strands with bubbles. I don't see any of that in your pictures.