Here's a slightly different question for everyone: What do you do with your old saltwater after a water change? I assume everyone just dumps it in some fashion. I ask because I'm curious if there is anything useful (and less wasteful) that can be done, but I doubt it. My questioning comes from the idea how I hear freshwater hobbyists seem to have good results when they use old aquarium water for watering plants they may have. Obviously we're not doing that with saltwater, but it would be nice if there is some sort of secondary use that it could have. I doubt there is, but why not ask?