My 90 gal tank has tan color gravel, not appealing, drab look or maybe, it's time for a change. This tank is set up for African Cichlids and I usually have a couple live bearers. My water is hard, PH 7.8, GH 150, KH 180, and no problems with Nitrate, Nitrite or Ammonia spikes. Regular maintenance schedule. I'm thinking of change the appearance to a white sand, maybe fine gravel, I have used Oolite and Afriican Cichlid Mix and I like the added benefits of CaribSea substrates that buffer, reduce water chemicals, retain PH.. The substrates that I have researched are; (mostly CaribSea) - Crystal River White Gravel - Nature's Own Aragonite Sand - Aragonite Selct Sand - Select Grade Reef Sand Any suggestions and comments appreciated.