Redoing an African Cichlid Tank

Hey Guys

First time poster long time lurker. I've kept aquariums as a hobby since I was about 5 or 6 years old (currently 28) and have upgraded tanks throughout the years. I ended up buying a 110 gallon tall tank about 6 years ago on craigslist, kept it in my folks basement for awhile until a few years back when I redid the whole thing (sanded down the crappy dull paint - built a canopy for it, repainted the whole thing black with gold accents). I've had it running smoothly in my apartment in NYC for while now but after 4 years its time for a reboot. All but a few of the cichlids have died off - and I was hoping to get a bit of advice in regards to upgrading the filtration, enhanced automation (i work in finance and time can be limited at times), tips on re-doing the gravel etc. I have been running it with two penguin biowheel 350's (so theoretically enough filtration) but it clearly needs an upgrade.

I would like to redo it while keeping the African Cichlid theme. I am trying to put together a shopping list so any feedback would be greatly appreciated.

Cheers!