[jpmwjm]

I have had my 75 glln tank up and running now for almost a month. The air pockets in the sand had all been worked out. I now have 52 lbs of LR and 10 lbs of caribean dry base rock. I noticed about a week ago I started to see lots of bubbles coming from the sand. If you look at the sand bed along the glass there are lots of very small bubbles thruout the top inch of the sand layer. I was wondering what would cause this since the sand had already settled out a couple weeks earlier?? I checked the water all seemed in line. I added a small cleanup crew for the algae (a little diatom and moderate amount of hair algae.) They have all survived well for four days. P.S. - the clean-up crew was added after, not before the bubbles started to appear.)

[glampka]

Probably nitrogen bubbles.

[barbra]

Nitrogen is my guess too.

[teajay33]

+3

[jpmwjm]

Thanks. That was what I was leaning toward, but I just wanted to see if anyone knew of any other gases that could do this. Is that a sign that the sand is becoming "Live"? I used the LR to seed it.