I am indeed doing a cryptic fuge (let's say harvesting any algae after a while gets old!!). I have always had a lot of luck with sponges, etc. and after reading a thread at the Central site I became very interested in the concept of the cryptic fuge. Basically, it is a DSB with a raised eggcrate platform with live rock for growing things that do better in the dark (read less heat from lighting, no algae, etc.). The theory is (and no I can't prove anything scientifically here) that the sponges, feather dusters, etc. will clean the water as well.

No matter what type of fuge you run, DON'T put predators in the fuge that defeat the purpose. People often drop off unwanted hitchhikers, sand sifting stars, etc. that eat the things we are trying to grow in a fuge. Calfo's book "Reef Invertebrates" gives an outstanding discussion of this whole topic.

I will post some pics of the my cryptic fuge tomorrow on my build thread. I don't want to hijack this thread because it is a great discussion. I did "T" off from my drain to this fuge and then I have (2) 1/2' bulkheads (they were what was already drilled on the tank) near the top. I put threaded/slip adapters that I turned sideways to skim off the top. This tank is taller than my sump so it gravity feeds the sump. I did this to avoid another pump and I wanted to use the "refuge" section of my sump as a frag tank.

Hope that helps.

Lee