I am just getting started setting up a 75 gal aquarium and I need help in deciding which substrate to use. My fish will be mainly Angels, BN Plecos and Kuhli Loaches. This will be a planted tank also. I have narrowed it down to sand or Black Diamond Grit . I have heard Black Diamond is too sharp for the Kuhli loaches and others say it is fine. Any advice from experience would be appreciated. Thanks