A typical RO system has four stages. First, a sediment filter catches sand and rust—like bouncers at a club for dirt. Then a carbon filter zaps chlorine, which smells like a pool but kills your filter bacteria. Then comes the membrane, the diva of the show. Finally, a polishing filter catches any stragglers.
For every 4 gallons you make, you get 1 gallon of pure water and 3 gallons of reject water. That’s a lot of waste, but you can use that reject water for watering plants—your ferns will be thrilled, even if your fish are judgmental.
Amazon.com: Geekpure 3 STAGE Portable Aquarium Reverse Osmosis RO
