My water is from a well and has a pH of about 7.8, I'm not sure of the hardness. I add a tablespoon of marine salt to 10 gallons. Further buffering of the water is done by the addition of crushed oyster shells to the substrate. I've always used gravel from local brooks that has been boiled to kill any unwanted visitors that may be introduced to my tanks. I find this gravel to be much nicer than anything you can buy.
Stones range from marble size to almost sand.
The dark coloration shows fish off at their best. I am keeping them in, decor is the same. I use shale fashioned into caves, and various sized seashells scattered throughout. I have kept and spawned brichardi in many different sized tanks, starting out with a 29 gallon and evolving to my present setup which is a 100 gallon species only tank. Every two weeks, about 10-15 percent of the water is changed.