I have a two-month-old 37 gal tank w/ 14 various Mbuna averaging 3" in
length (and 1 plecostomus). I'm planning to return selected fish to
the LFS as they outgrow the tank. This will let me pick them out by
sex, coloration and sociability as they mature.

The tank has a Marineland "Eclipse3" hood. The lighting's nice (two
full-width flourescent bulbs) but I'm worried about overloading the
integrated filter.

I have a big bubble wand, so aeration's not a problem. And the
impeller seems to move an enormous amount of water. But the 10" long
filter floss/carbon cartridge is not very substantial. The
bio-wheel's about 8" long.

I've been thinking about pitching the Eclipse hood and getting a
300gph external unit. Is this necessary?

Though the ammonia appears to be under control, I have not been able
to get the nitrites to stabilize. Most of the time the nitrites are
at about 2.0 When they get to 3.0 I change out 1/3 to 1/2 of the
water. I've been trying to vary the amount of water changed, to see
if the bio-wheel can get on top of the nitrites, but that doesn't seem
to make any difference. A couple times when the nitrites have spiked
up pretty quickly I've changed 2/3 of the water. I'm averaging 3 to 4
changes per week. The fish do not seem to mind the changes -- there's
very little clamping, and they're all breathing well.

I lost three fish the first few weeks, but only one in the last month.

One of the girls at the LFS said that ammonia chips are almost a
necessity with Africans. So I've just put a bag of zoolite on top of
the filter cartridge. I suspect that this will eventually do the
trick. Should I count on always needing the chips, or can a biofilter
handle the nitrogen cycle unassisted in this tank?

Do most of you use ammonia chips for your Africans?

Should I ditch the Eclipse hood? It'd cost about $100 to replace it,
so I'm reluctant to abandon it if I can make it work.

Any thoughts?