Thanks for all your help, Russ. I am very happy with my new 5 stage RO/DI unit from BFS. I have made about 200 gallons of new RO/DI water since I purchased my new water purification system and I am still at zero TDS, which I could never obtain (emphasis added) with my previous RO/DI unit. Russ also gave a very nice presentation about RO/DI at the March/April Ohio Reef meeting as well.