Going to set up a Cichlid tank have some questions first

[T&C Exotics]

So my son is obsessed with fish and I am going to be setting up a african cichlid tank for him. The reason I am choosing this kind of fish is due to the absolute beauty of them. Now that it has been decided what kind of fish we are going to have we had to choose a tank. We chose a 90 gallon. So first few steps were pretty simple. Next thing is setting up the tank and then making the purchase of the fish. So that is where need some help. I know there are 2 species, 1 from africa and one from south america. We are going with the african species. I have done some reading and still have no real idea what to do to set up the tank. I have not found anything stating what levels are acceptable for the tank and also not found anything saying what would be best for the substrate and for the hardscape. So some help there would be totally awesome. Also what is the rules for fish per gallon? I have read one inch fish to one gallon but also read that with cichlids it is 2 inches fish to one gallon water. No clue how to go about that and do not want to mess it up. Lastly what would be the best diet to feed them?

I hope I was clear on what I am planning on doing and what I need help with. Thank you in advance for any help here.

[DooLittle]

I would stick to one inch of fish per gallon. Cichlids are fun to watch. They will dig out and rearrange the tank to their liking too. Many of them will also get quite large.

[theNotoriousDUD]

for your substrate try to use some form of crushed coral. I used a coarser grain of crushed coral but I have kicked myself for not using coral sand instead(it just looks better). Over filter your tank as much as possible, for a 90g I would go with a 3 filter system, I use 2 canisters and an appropriately sized sponge filter. You will find that the more fish that in your tank the less aggression will occur. Have a great time and do a TON of research when it comes to Africans you are probably going to find a species you want to add weekly if not more often. This is the site I joined when I was starting out in African cichlids, the folks here are great and alot of help is available. http://www.cichlidforums.com/activity.php. I could go on for months about the things I have learned in the past 10yrs, joining a forum is the best way to get the info you need.