12-15-2016, 03:58 AM
Join Date: Apr 2006
| | Re: Refugium input wanted!
Originally Posted by ChrisKane
My current concern is the color I'm seeing in the substrate (red? and cyanobacteria?). It's my fault for allowing my bounce cards to be kicked out from the refugium which then bounced light at the soil. Since then I've removed the bounce cards until I can cut a slim piece of black foam core and tape it to the bottom.
What type of alga is the strawberry red I'm seeing?
It might be oxidized iron. In my bottle tests, I often got a pretty pink layer in the soil layer just under the top sand layer. This happens in the dark. Iron in the soil solubilizes under the anaerobic conditions at the soil bottom and percolates upwards. In the meantime, oxygen penetrates through the sand layer and percolates downward. When the two meet in the middle, the iron oxidizes and forms a layer of pinkish-colored oxidized iron.
In your case, since light seems to be a factor, it could be the purple photosynthetic bacteria, which require light. Some of the purple bacteria oxide toxic H2S (hydrogen sulfide) to non-toxic sulfate. These are very good soil bacteria that there is no reason to discourage.
I agree that you have a very impressive setup!