Thinking about a new bed style?

[misterguppy]

Currently I have a 4' x 10' DWC raft bed and 12 55 gallon half barrels filled with rock. The media are divided with 6 constant flow and 6 siphon. I am thinking of turning the Media beds into a combination bed with about 10" of water space and 6 inches of rock on the bottom for the bacteria. Will this work, or do the bacteria need oxygen for conversion? I am tired of the individual small beds with each one having its own fill and drain system. Currently I have 4 barrel halves in each table (3 tables). I am wanting to convert them to one fill/one drain per table beds to make it easier to manage. Any thoughts/information?

[eddiemigue]

Do you have dedicated solids and bio filtration? If so, I'd just convert everything to constant flow, whether media or DWC. A combination DWC/media bed might make it difficult to clean.

[misterguppy]

I have a solids filtration system in the form of one 55 gallon drum as a radial flow filter flowing into a 55 gallon drum swirl filter and then into the sump tanks. I do not have bio balls. My thought was to reuse the expanded shale I already have as a biofilter in the bottoms of the new raft tables. Would I be better to use a couple of drums filled with the shale and and run air into the bottoms as a bio medium?