i assume you are talking about diatoms? Your clean up crew, such as snails would eat it. But getting an RO or a DI until isnt only for getting rid of diatoms in your tank...... It takes out all the contaminents, makeing your tank safer for your inhabitents, and also keeping your water cleaner. A good investment IMO. Heck, I got my DI system online for only 30 bucks.