I've been considering getting an RO
unit lately (maybe Santa could help me out this year). I have a 75 gal
reef tank and do 20% water changes every other week. Could anyone please let me know what is involved in maintaining one? I've heard of having to replace filters for it every so often. How much do they generally cost and how often do you have to replace them? I've heard of having to do water tests to see how pure the water is. What do you test for and how often? Any feedback would be helpful.