Speaking of "Hardware Stores"..... I buy enzymes for septic tanks and add it on big water changes. It's all natural beneficial bacteria 3lbs for $10 bucks. Petsmart sells the same +|>~% for about $4 and it's a tablespoon. It looks like saw dust and eventually settles and filters. Can't really over do it either. I have several tanks, my small fish eat it totally harmless. Good luck with the rbp's that's a Hell of a starter tank!