brown spots on sand?


My 55 reef tank has developed brown spots on the sand. It has been up for about 2-3 weeks. I bought live rock that had been cured for awhile, so I've bought 2 cleaner shrimp, a pajama cardinal, and a firefish golby, clove polyps, and green mushroom coral. what is this from? if a picture would be helpful I can post one, let me know. thank you.


I can probably bet that what you have is a small diatom bloom. Its natural and occurs occasionally. It will go away on its own eventually by natural causes. No worries.
Feel free to post a pic, though. I could be wrong.


I had the same problem until I got some Nassisarus snails(sp?). I had to stur my top layer of sand everyday. Now I don't even have to do that anymore. A queen conch or two will also help.


I have the same problem with my 55. It occured right after I put in my first batch of LR. It looks like a brown blanket on my LS. is it bad?? unfortunatly I don't have a camera to post a pic.

nm reef

Active Member
Definitely sounds like a diatom bloom...very common with newly cycled tanks and will normally go away on its own. Of even more concern is the rapid stocking of a newly cycled tank. Lots of stuff added to a 2-3 week old system in my opinion.I'd urge you to closely monitor your water chemistry and watch for any problems to develop.:thinking: