I have a 55g Malawi tank, I'm just running a standard 50 gallon filter. African cichlids, despite what you may hear are actually quite low maintenance don't be too concerned with chemical balance. I would recommend a pleco (they're the only algae eater armored enough to stay alive) to keep your tank clean. Cichlids like to dig so fine sand might be a good idea. As for types/numbers I would recommend over crowding to prevent targeted bullying (African cichlids won't refrain from breeding or stop growing do to over crowding). Female Kenyis, yellow labs, cobalt blue zebras, red zebras, auratus(male or female) and Acei are some good types. Make sure to get at most one male per 3 females. To keep cichlids healthy and active create as many rock coves and caves as you can. Don't be too particular on the decorative arrangement because the fish will dig and move things around.