Scott B. here. Extremely new to the hobby, 2 months. Bought an existing 75 gal tanks with coral and fish. Everything is going great but I have a question on my RO/DI. I have a BRS 4 Stage Value plus system. I replaced all of the filters and the membrane yesterday. The TDS is sitting @ 002. I know it should be zero but I have run this sucker for hours, flushed the membrane and still sitting on 2. Prior to the filter changes, I was zero. Any ideas? :headwallblue: