I'm planning on setting up a 29 gallon FW tank and would really like to use black substrate. I've read up on the Black Diamond 20/40 "sand" and the pricing is great, but I see (on Drs. Foster & Smith) a Carib Sea Instant Aquarium Tahitian Mon Reef sand. It's much pricier, but got very good reviews. I'm curious what makes people choose one over the other? Also, having always had gravel substrates and being used to vacuuming the gravel, what should I know about keeping the sand clean? I'd like to plant live plants and have a school of corys.