Hello everyone! I'm in the process of setting up my first saltwater aquarium, a 150g 60x24x24. I have a BRS 6 stage RODI 75gpd unit. I finished my salt mixing station back in June and decided to go ahead and try it out although I was not ready to fill the tank. I made 100g of RODI and my TDS after the membrane read about 20-40 typically. After a total of about 150g of RODI, I had depleted almost one cartridge of DI resin. I stored the RODI until the beginning of August when the tank was ready to be leak tested and filled. Once I got the tank filled, I started to make more RODI. The TDS after the membrane all of sudden started reading as high as the 180's! I went through a whole cartridge of DI resin after only 20-30g, and it seemed to take much longer to make RODI water. I live in Indianapolis. The average TDS straight from the tap is around 400TDS with some areas a slow as 200 and some as high as 600. My pressure has consistently been at 50PSI both when it was working right and now. I contacted BRS and they suggested maybe a faulty membrane, so I bought another. Made no difference. I have run another 40g through the new membrane and am still getting readings in the 160-190 range after the membrane. The TDS after the first and 2nd di cartridge does read 0, but like I said, I am going through DI resin like crazy.. I contacted a LFS that uses city water, and they have not experienced any problems that they are aware of. Any ideas what the heck is going on? For good measure, even though I detect no ammonia in the RODI water and my pressure has not dropped, I replaced both carbon blocks and sediment filter. It made no difference.