| | Re: Easy DIY automatic water change system for less then $50
Well not really, all the water tubes in your house are made of copper and we use them for fish tank water. Also, metallic copper doesn't dissolve readily into water especially if it is cold water that is not exposed to the air. Alternatively if you are worried about using the copper ice maker kit they sell a plastic alternative that you can use in the exact same way.
I chose not to go with a sump, because that adds another layer of complexity to the system, and with more complexity comes more of a chance that something will go wrong in the system and cause an overflow problem.