Have been looking on ebay and have noticed RO units going for under 100 bucks. Would it be worth me buying one of these to prepare my water for keeping discus, i am not looking to breed them at this stage so am wondering if it is worth buying one or am i better off to just filling up my water change drum and tweaking the parametres in that untill its right for my fish? I am not keeping discus yet just trying to gather as much info as possible before i take the plunge. thanks in advance. Benno