Purging sand

[asylumdown]

So I know there's different ideologies on dealign with sand beds, but not so long ago I got the bright idea to turkey baster my sand. My logic was a) I have no siphon vac and I never siphon water from my display so I wasn't going to do that and b) my sand was getting disgusting from where I could see it through the glass, bubble algae was actually growing BENEATH the surface of the sand, cyano was starting to cover it, dinos bloomed and faded on it on a regular basis, all while my rocks were algae free and my corals were growing like gangbusters. I figured there must be something in the sand that was feeding the algae that wasn't making it in to the water column, so I decided to turkey baster the heck out of it to hopefully fluidize the gunk so my filter socks and skimmer could suck it out.


Fast forward about... 2 months? I've now done it three times (tonight being the third). I've noticed that in the sections where I've done a thorough turkey bastering so that all algae of any kind is completely removed and the sand looks new, I'm seeing TONS of bubbles forming inside the sand against the glass. Sometimes as shallow as 0.25 inches below the surface.

At its deepest, my sand bed is maybe 3.5-4 inches, and that's only in a couple of spots. I didn't think that was deep enough for anoxic denitrification, and I certainly didn't think you could get denitrification a quarter inch down. Are the bubbles I'm seeing nitrogen, or O2, or CO2?

Further more, the bacteria that do the denitrification, are they a specific group of anaerobic-only species, or are they also facultative anaerobes that will consume oxygen if it's present, but switch to anaerobic consumption of nitrate if O2 levels fall too low? In the former case, I'd be torpedoing any denitrification potential my sand bed has by blasting with a turkey baster and fluidizing everything, but in the latter case denitrification should start up again within less than a day of disturbing it.

[darkreef]

I do this to my rocks every night before bed and before water changes .
Also hit corners where stuff builds up on my sand !

[toytech]

Don't know what the bubbles are but I had them in my 2 inch sand bed as well just under the surface and algae growth on the sand too. Tried manually moving the sand and that didn't work so I got a fighting conch and cerith snails that fixed it in about a month . Fighting conches I think are a must have , they do such a great job on a sand bed without causing harm to sand fauna.

[asylumdown]

Yah I've got 5 fighting conches, they're pretty awesome at keeping any sort of macro algae at bay, but they won't touch dinos or cyano. I've pretty much only got 3 kinds of algae in my tank - cyano, dinos, and this small vine like plant with teeny tiny little serrated leaves that only grows in between corals where my tang and rabbit fish can't reach.The cyano recently has been getting a little out of hand and it's starting to drive me batty, which is why I thought I'd try fluidizing the sand to get as much garbage out of it as I could. It doesn't seem to harm any of the sand dwelling life, within an hour of doing it I can see the burrows of tiny worms starting to form again, and it sure makes the sand look cleaner, just not sure what it's doing biochemically...

[Leah]

I always siphon my sand whenever I do a water change. I like my sand bed white.

[Slyguy00]

Originally Posted by Leah

I always siphon my sand whenever I do a water change. I like my sand bed white.

+1. I always syphon my sand and keep it white. Usually have no issues at all. Except the last time i did it. I did an extra good syphoning and it appears to have disrupted something because i have a thin brown layer forming on sand. Not sure why though. Perhaps started a mini cycle by disrupting to much at once?

[FishyFishy!]

Hey adam, this is a cool read on sand. It's a long one, but it does a lot with the chemistry aspect of things.

http://www.reef-eden.net/DSBs.htm

My guess on the bubbles would be nitrogen.