So since I grow hydroponics I got an RO system that I attached to a trash can I use as a reservoir with a float valve and the wastewater line going down the washing machine stand pipe(pretty sure that's what its called). Well I just assumed when the tank was full and the float valve cut it off the waste water would naturally stop too since its no longer flowing through the filters. I was wrong and got a little surprise on my water bill. God only knows how many hundreds of gallons I wasted. This is the only RO system I have ever used. Is this normal or do I just have a cheap RO system? Has anyone else experienced this and found a decent work around? I can always just go back to setting timer for 30 minutes a gallon but I'm trying to find something that takes place independently of myself.