I just purchased the 200 GDP RO/DI by Aquatic life. Seems like a nice unit. Had some issues getting it to work but it now up and running. The one issue is that my total output of TDS is at 13-14 PPM not 0-1 PPM which is what I was expecting. My tap water is ~240 PPM and everything I read says the unit should bring it close to zero. I am guessing something is wrong. Other posting indicate the DI resin is spent but it brand new. Anyone have any ideas what going on and is 13 PPM acceptable for my tank or am I going to have issues.