I think the undergravel filters aren't too good these days ya know. Your better off with the hang on back filters. I highly reccommmend canister filters as well
UGF are actually a fine way of filtering an aquarium for those who are on a tight budget or do not want to deal with things hanging on the back of their aquarium. But 3-4 inches is much too deep IMO. The flow will be restricted and will be less efficient. 1-2 inches is enough.
I would advise looking at finding a reversible powerhead sometime in the near future if not now. RUGFs are excellent!
actually i am already usind canister filter in my discus tank, but just wondering wht will be the result of using thick gravel with ung. just want to know
you can either use UGF or RFUG.
the filtration system themselves are not bad..many experienced fish keepers use them with few problems.
with rfug/ugf the entire bed becomes a biofilter.
you do have to be diligent with your cleanins tho.
and I much prefer RFUG over UGF..but I have to admit..my 55 with UGF powered with powerheads is the cleanest tank and remains the easiest to maintain.
yep one more thing, is it possible tht some colonies of nitrate digesting bacteria will might grow there coz i think tht there will be less oxy present in the bed due to thick layer of gravel like 4 inches