Bubles rising off sand bed are back

[Ronny#66]

just returned from overroad trip to Michigan. Checked 25 gal tank and the bubles are on all pipes heater ect. When I left monday there were no bubles none on sat or friday amonia 0 ph 8.4 nitrite 0 nitrate 0 . why do they come and go and they seem to apear with full lighting none hardly with moon lighting.

 

[drummereef]

Is there any algae associated with the bubbles? Brown, stringy? Bubbles in the substrate are a normal part of the nitrogen cycle.

http://www.ronshimek.com/Deep Sand Beds.htm

 

[Ronny#66]

Had a green algea outbreak last week but mostly gone now. Bubles went away for a while . How come you never see them in LFS tanks?

 

[Gdevine]

It's just oxygen given off by bacteria. Usually happens later in the evening with lights on for a while.

Totall normal and really...not a big concern.