Grey spots in sand

[Dr]

I was cleaning the tank the other day and noticed that my sand bed has some areas that are grey. Could this be the sand bed crashing? Should I remove all the sand and start over?

Thanks

[bertoni]

It could just be some cyanobacteria. Is the gray area a film that blows off easily, or is the sand forming into chunks? A search on cyanobacteria should turn up some information.

[Dr]

It's forming into chuncks under the surface of the sand bed.

[Teremei]

BTW what's all this about the sandbed "crashing" I've heard people say Shallow Sandbeds need to be replaced every so often or it "crashes". .

[bertoni]

Okay, how deep is the sand? What sandbed animals have you stocked?

The clumping is probably a sign that the tank needs more animals in it.

[Dr]

That's funny because I've heard that deep sand beds tend to crash after 4 to 5 years.

The tank has been set up for 1 1/2yrs and bed is about 1" ,some spots more, some spots less. I had nassarius snails but all of them died. So I tried adding more, then they all died. Now I have 3 scarlet hermits, 1 large brittle star, 12 astrea snails, and 1 turbo snail.

[Teremei]

Not enough sand sifters for a 75 IMO. I have a 55 and have 13 astreas, 8 nassarius, 20 blue legged hermits, 3 scarlets, and 1 emerald crab. (and will probably get more nassarius). .

I have heard some people say if you can keep SSB stirred up more often it is good for it's health. But I still don't understand what people are saying about sandbeds crashing. People link to that article ofcourse but it doesn't get right to the point about what actually happens.

[bertoni]

I'd just remove the sand and replace it. You should be able to siphon most of it out fairly easily, or you could just remove the areas that have hardened.

[Dr]

Thanks Teremei and bertoni,

I think that I'm going to remove the bed and start over. When I add the new sand, should I add like a cup per day?

[bertoni]

If it's clean, you can add it all once, IME. If you want to be careful, you could try smaller additions. It's really up to you. I added a 6" sandbed once to a tank with no problems.

[Teremei]

What I plan to start doing is every once in awhile vacum up the top layers of sand (whichever parts I can get to that aren't blocked by rock). . This will not only lead to super clean white sand but will also allow me to replace with new sand, little by little. I think this is the best way.

[Dr]

Thanks for all the help!