sand or crushed coral

ok so after doing a bunch of research and breaking down my sps coral reef tank i have decided to set up an african cichlid tank. well i have just a few questions.. i have both extra bags of reef sand and crushed coral from previous saltwater fish only and reef tank setups. should i go with crushed coral or reef sand? i know the crushed coral is kind of bad for saltwater because the coral is porous and traps waist which causes high nitrates and phosphates. is it the same with freshwater? what works best for africans. i never used crushed coral or sand in any of my freshwater setups since most of the fish i keep are south american and low ph is required. thanks for reading my paragraph

i was thinking about black.. which would you say looks best.. i think there is some sand called black moon sand? i keep all my cichla with fine black gravel. i think black sand looks the best in my opinion. i will deff go with sand then. i have to figure out which color to choose though.

as for what type of cichlids. i lovve haps, ruby reds and electric blues... buttt i saw some sweet jet black tangs that had this wide bright orange horizontal bar. for some reason now i can get get them off my mind. this is all new to to me so im guessing tangs get big and dont know if i can house them in my tank.