While reverse-osmosis units are among the more practical, affordable means for producing purified tap water suitable for sensitive reef systems, there’s no question that they generate a lot of waste water relative to the volume of purified product. In fact, they often produce upwards of four gallons of waste water for every one gallon of purified water. It’s only natural for conservation-oriented hobbyists to look for ways to reclaim this waste water and put it to meaningful use rather than send it swirling down the drain. But finding realistic ways to use all that water isn’t as simple as it seems, especially if you have a relatively large aquarium system and, therefore, need to produce a hefty amount of RO water on a fairly regular basis.
The usual advice is to use the waste water to give your plants or lawn a drink. These are certainly valid options, but let’s face it, you’d have to have an awful lot of plants to keep pace with all the waste water produced. And as far as watering the lawn is concerned, I’m sure someone more inventive than I (which isn’t saying much) could find ways to do this efficiently using RO waste water, but I haven’t figured out a method that would work for my yard yet. MORE