What do you think of this?
I can easily make a tower 60cm tall x 30cm x 16cm out of acrylic. Within this tower, there will be a few 1.5cm x1.5cm acrylic bars cemented on that will allow me to make shelves inside of it.
Water pours in the top, and I drill holes in the bottom 6cm. This allows (forces) water to through the tower and out the bottom.
The top layer would be coarse pad, with some less coarse pad under it, followed by sponge or fine pad. The top couple of layers are there to catch particulate and prevent the the subsequent layers from getting clogged up (and can be easily cleaned/maintained)
Middle layer- 6-10cm coarse substrate, sitting on top of the very coarse pad.
Bottom layer- 10-15 cm medium grain substrate —> small grain substrate on top of a final pad or sponge.
Bottom layer would be 6cm off bottom of filter. Holes drilled in acrylic along bottom of tower beneath bottom layer.
I could run any volume through I want, but it seems like maybe ~400 lph would be a good start.
Don’t you think that by the time that volume of water percolated through ~30cm of pads, sponges, and then coarse substrate that pretty much all the available O2 would have been used, and then the bottom 10-15cm of substrate would facilitate anaerobic activity?
I kind of want the bottom of the refugium to just be some fine substrate and then just let detritus from the tank settle in. I want to keep that ‘mud’ layer unencumbered, so I don’t want any rock on top of it. I can even install plastic grid baffles a couple of cm off the bottom to allow the macro-algae to anchor w/o anything actually being on the bottom. Extra live rock can be piled in the chamber downstream of the refugium chamber...for sponge growth, micro-inverts/detritivores, etc etc.
If you look at the pic of the sump, you can see that at one point I had made a 5cm hole between to two boxes. This height is approx where the current skimmer effluent line is. Thinking of running the effluent water back into the other side into...whatever. And I guess there is nothing stopping me from raising the skimmer off the bottom of the sump and then running some of the effluent back to the drain chamber and dump it into the bio chamber.
Thoughts?