Fishless Cycle - Sand Bed Turning Brown?

[EternalNY]

Hi, long time lurker, first time poster.

I recently tore down a 55 gallon freshwater tank and set up a saltwater tank.

I am currently doing a fishless cycle. I put in about 4 inches of crushed coral and another inch of live aragonite sand. I have a couple live rocks, and added ammonia to kick off the cycle. So far, so good.

When I returned from the July 4 holiday, I noticed that my sand bed had turned from white to a brownish color anywhere it had direct light (it is still white in areas around my rocks where there is less light). The ammonia has run through its complete cycle, and I am now waiting for the nitrites to come down.

Should I be concerned about this, or is it normal for a sand bed to turn colors when the tank cycles? The fact that its only in areas with direct light makes me concerned, because I thought the cycling bacteria don't thrive off light, only ammonia and nitrite.

I am running only 2x15 watt Coralife lights right now, with upgrade plans in the near future. I guess I am concerned about algae or some other unwated growth.

Thanks!

[Gem Tang Rider]

Sounds like brown diatom algae. Usually goes away after a couple of months. Certain snails will eat it, but research that they won't eat your additions later on.

[Astros]

I agree with prugs. I have some astrea and turbo snails that love the stuff, but will only take it off the rocks and glass, not the sand. Nassarius are good for your sand bed, and won't kill anything in it, but I don't know how well they would do in a newly cycled tank. You probably want to wait to add anything though, until your nitrites are at 0.

Paul

[Sari1501]

I agree. Definitley sounds like diatoms. I had the exact same thing happen when my tank was nearing the end of its cycle. Some of it went away with time, the rest was taken care of by the cerith snails (one it was cycled).

Don't worry about it. Your tank will go through its own "algea cycle" and this is just the beginning...

It's an ugly thing to look at but as the posters above me said ~ Just the natural process... it will get better in time. In a few months for a sand bed clean up crew~ Nassarius, Cerith and Conch snails will keep the surface of the dsb sparkling.
Along with a mature bed of worms=spaghetti, bristle ect...

[EternalNY]

Thanks for the comments all.

It's great to have a place like this where you can get a quick answer from people who have seen it before. I guess I won't worry about it, and I'll pick up some snails when the cycle is complete.