How to put a UGF in an 8' Tank?

[wookish]

I am building a similar setup with an old lobster tank, pictures and thread to come soon. I think they are right, use your canisters or externals as themselves (ie not attached to UG filter) or better when attached to a dual water column and surface skimmer. If your using it for an aquaponic system, you need bacteria to break down waste into useable nitates for the plants. And yes an UG flter will do so, but as they mentioned inefficiently. And why filter poo out before your plants get at it? I suggest using a pump from aquarium to a (possibly elevated) chamber containing biomedia, aeration, then directly into grow beds.. then perhaps collect and run it through your mechanical and/or chemical filtration and finally returning to the tilapia tank. Use the plants as your filter workhorse, that's the beauty of the system. And note you will never want to fully interrupt the bacteria growing on the filter media if you have plants in the growing trays. And keep the water in the dark, algae bad.

I have a glass 80 gall FW for show not for aquaculture, and I need the Undergravel filter for safety, not filtration, to support the weight of large rocks in the tank. I have used UGs in reverse with powerheads in the past; but as Fat Homer said, do not attempt this with any fine substrate. I believe I have read that it is good for planted aquariums to do this, or to use snails to turn up the gravel. I currently use just a Fluval 404 with the surface skimmer attachment, a thin layer of sand on the UG filter, and vaccum and water change every month with no problems.

thats my $0.04

 

[Veil-o's]

Eggcrate at the bottom for even dispersion of weight from the rocks on the bottom. Add a nice sand bed (pool filter sand requires less washing and doesn't cloud the water as much when first setting it up.) Buy yourself an FX5 and a couple of well placed power heads and you'll never have to worry about dead spots.

There are people who swear by UGF systems and people who despise them. It's really up to you how you would like to do it. There are UGF inserts that can fit a variety of systems. RUGF systems that are well thought out can keep debris suspended in the water column until your main filter picks it up (youtube reverse undergravel system). An FX5 going to a RUGF system is no different than running a gate valve on the return to slow flow because of the added head going deeper into the tank. If you do end up going with an UGF you will want to use gravel as a substrate because as other people have stated sand can clog the plates and will get continuously sucked up the powerheads. The choice is yours.