Filtration for a deep tank like that with such a heavy bioload IMO should be an AC110, and the rena xp3 if you like that. Possibly backed up by another HOB if the budget permits. Would also recommend a 250 watt heater minimum. The list 850R suggests is, as stated, a start but the only way to really learn about the temperament of the fish is to research them individually. It's not as hard as it sounds, just a bit of reading. I chose to overstock my tank in the beginning when I first had mbuna and it resulted in losses, so be careful as escamosa has mentioned. In a newly cycled tank it can cause ammonia spikes to add a large number of fish. However, I currently have 18-20 or more fish(anywhere from a half inch to 4.5'+) in my 75 and it really spreads the aggression out, the affect is noticeable. Now, as has also been mentioned, the tank does not have the appropriate footprint which is the main factor in determining whether or not a fish is appropriate for your tank. I would again go with escamosas advice here, but I personally believe you could get away with adding UP TO 4 more fish, for a grand total of 12.
I also have syno cats, which I would suggest looking into if you like bottom dwellers.
The difference between petricola and multipunctatus is, essentially, price and availability. I payed 25 dollars a piece for my Synodontis Multipunctatus which adds up quickly with schooling fish. Also I am not 100% positive but I think the petricola cats stay a bit smaller.
Also, make sure you use some sort of aragonite sand or african cichlid sand just to aid in keeping the water hardness and such in check between water changes.
Last edited by Northerly; 12-04-2012 at 02:13 PM.