Black patches on live sand

[k1ngofthrones]

A few weeks ago I started noticing black patches on my live sand, it causes a small layer of sand directly underneath to clump together, sorry if the pictures are blurry. Is it algae, and if so, what kind? How can I prevent it? I had a huge cyano problem, but Herbtana worked like a charm so now I only get a little bit on the glass. I think it started after I got a piece of live rock but I am not sure.

 

[bsr2430]

Looks like Cyano, just not red, is your sand bed deep?
Are you moving your sand when doing maintenance? That could be causing this issue.

 

[k1ngofthrones]

Looks like Cyano, just not red, is your sand bed deep?
Are you moving your sand when doing maintenance? That could be causing this issue.

My sand bed is not very deep, it’s a 40G breeder with 40 lbs of live sand as the only substrate so it’s probably 2 inches at the most at its deepest parts. I try not to disturb the sand bed because I’m afraid of there somehow being ammonia pockets, since my tank is relatively small I’d imagine it wouldn’t take much to ruin my tank

 

[bsr2430]

That’s actually a lot of sand. You should only have 1/2-1 at most. Your sand is probably hiding all kinds of problems. As long as you never mess with it. Then it shouldn’t be that bad, as far as the black patches, that will remain unless you make change. You could easily take sand and cover the black spots, but that’s like putting a bandage on it.

what’s your flow like right now? Is your tank getting enough flow to pick up junk off the sand without destroying your sand bed?

 

[k1ngofthrones]

That’s actually a lot of sand. You should only have 1/2-1 at most. Your sand is probably hiding all kinds of problems. As long as you never mess with it. Then it shouldn’t be that bad, as far as the black patches, that will remain unless you make change. You could easily take sand and cover the black spots, but that’s like putting a bandage on it.

what’s your flow like right now? Is your tank getting enough flow to pick up junk off the sand without destroying your sand bed?

Really? I always thought it was shallow. I don’t have a power head so my flow isn’t the strongest but it’s enough so that there’s not really any food left on the bottom, I turn the filter off when I feed and when it comes back on it does a good job of keeping food off the bottom. I don’t have a lot of livestock (3 small fish, a coral banded shrimp, emerald, and scarlet hermit) so I don’t put in a lot of food anyways. Do you know what exactly the black spots could be?

 

[ca1ore]

Naah, 2” of sand isn’t a problem. You’ve got to go to at least 4”, maybe closer to 6”, before you start getting anaerobic nasties. The black patches look like cyano to me.