That should be PLENTY. Just watch your feeding (don't overfeed/skip a day twice a week even, cichlids are TOUGH, and it's better for them like in nature).
Air driven sponge filters are SOO much more beneficial that people realize. Slow biological filtration TRUMPS high flow ANYDAY other than for "looks".
I've over bought filters for YEAR's (because I like to experiment), and I can't say ANY of them were really any better than the others as long as you have enough bio media (HydroSponge is an EXCELLENT BIO Filter, I use them religiously), with a good water change schedule that you STICK TO. Of course the LOWER your stock the longer you can get away with less frequent water changes/gravel vac's.
Next to adequate bio filtration, regular water changes are THE SECRET to a beautiful aquarium, NOT the name brand , or amount you spent on the filter you use.
Hope this helps!