The only draw back on the tube filter is that your water may not be as crystal clear as you would expect with a canister filter. I would suggest using filter socks for your sump over flow when it hits the sump. It will help a lot with mechanical filtration. You can get some more help cleaning the water with a big sponge on the intake of your return pump. Just make you change them regularly so they don't fill up (especially with the return pump - don't want to starve the pump).
For bio media, any of the stuff will work, like the Eheim stuff, BRS stuff, aquaclear bio pellets, etc. Since you are stuffing this stuff inside a tube filter, you need to make sure a) it doesn't pack and b) it promotes random flow through the filter. The best stuff for that (IMO) is the rod/cylinder shaped stuff. I prefer tri-pelitized carbon from Hiatt -tons of surface area for bacteria to grow and carbon source to help establish the bacteria. I think I got a pound of it somewhere if you are interested.
The big question is how much? We'll, think about how many cubic inches you would expect to need in a canister filter, and it will be about the same. The BRS bio media and tri-pelitized carbon have a fair amount more surface area than the stock canister filter stuff, so you can get by with even less space. Then figure out what diameter tube you want to use. If use 3" diameter pipe, then 11" of pipe (1 foot less 1" for filter floss) would give you roughly 78 square inches of bio media, which is a lot (area of cylinder = PI * Radius squared * length = 3.14*1.5*1.5*11 = 77.71square inches). Use 2" diameter, and it is 34.5 square inches. The benefit of smaller diameters is it minimizes the potential for flow issues like dead spots and channeling through the bio media, and you usually use a smaller pump. But you will be limited by the size of your sump.
Make sure you plan something that helps keep the tube and pump off the floor and sides of the sump or you can get a fair amount of noise. I used nylon rope to suspend it from the top of the stand. It is still fully submersed, but it is not touching anything but water.
Bio balls seems to generate nitrates quicker than just about anything else. I always thought it was the whole wet/dry thing. On the flip side, it is ripping any ammonia and nitrites out of your water faster than most. So it is a double edged sword. IME, cichlids can tolerate some pretty crummy water conditions, so you have a lot of flexibility. You are much better off getting the ammonia and nitrites out of the water as quickly as you can (i.e. a very efficient biofiltration set up, whichever way you go) and dealing with nitrates as they occur. The good news with African cichlids is that San Diego tap water runs Ph in the low 8s (at least it has for me), and they generally like higher Ph. So water changes are a breeze, as long as you get the temp right when doing fill ups (tons of articles out there about the problems with using water warmed by your hot water heater...better to use separate container, fill up, hit it with dechlorinator/heater/small power head, and then pump into system).
If you do go tube filter, PM me and I'll give you some suggestions on how to make it. For instance - put a screen over eggcrate at the end of the tube to keep the media from pouring out.
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Originally Posted by Sailor Seth
