FirstContact
Active member
So this year I added a second membrane and booster pump to my RODI. The booster pump from BRS has worked great. The add on membrane kit not so much. Basically, I think the waste water from the first membrane fouls the second membrane very quickly and then you just wasted $45 on the membrane and throw more money away on DI resin. Okay. Booster pump has worked great though.
I'm only feeding my first membrane about 125 ppm TDS. The waste water output from the first membrane is 185 ppm TDS. A second membrane should be able to handle that right? My water pressure before the first membrane is 85 psi. No issues with the first membrane at all; so, it can't be a problem related to the prefilters or water quality. This is the second membrane I have tried as a dual stage with waste water feeding the second membrane from the first. It definitely just doesn't work for any reasonable amount of time. I put a new membrane in the second stage in April. It now runs at 35 ppm TDS with the flush valve open and 50 ppm with the flush valve closed. I always get several years out of my membranes except this dual stage set up where the waste water goes to the intake on the second membrane. Starts out great measuring at 2 or 4 ppm but that doesn't last and the membrane is quickly fouled. My first membrane puts out 4 ppm TDS. Based on advice from BRS, I tried reseating the second membrane. Nope, doesn't work. Swapping out the RO tubing making the second membrane the first and the first membrane the second doesn't work either. It runs 28 ppm TDS with the flush valve open. That just proves the membrane is fouled. My HM Digital TDS triple in line meter is new and installed correctly. Also have a Hanna hand held. So there's really no way for the first membrane to continue to work great and the second membrane to fail so soon except for the fact that your feeding it highly concentrated waste water from the first membrane? Right?
BRS says this works for them long term and that their TDS from their second membrane runs about 7 ppm. I spoke with them Friday regarding troubleshooting. I'd love for this to work, but I can't see trying this with a 3rd membrane unless someone can tell me what I'm doing wrong.
Anyone have any thoughts? Does this work for you? What's different about my set up? Does this not work for you also?
I'm only feeding my first membrane about 125 ppm TDS. The waste water output from the first membrane is 185 ppm TDS. A second membrane should be able to handle that right? My water pressure before the first membrane is 85 psi. No issues with the first membrane at all; so, it can't be a problem related to the prefilters or water quality. This is the second membrane I have tried as a dual stage with waste water feeding the second membrane from the first. It definitely just doesn't work for any reasonable amount of time. I put a new membrane in the second stage in April. It now runs at 35 ppm TDS with the flush valve open and 50 ppm with the flush valve closed. I always get several years out of my membranes except this dual stage set up where the waste water goes to the intake on the second membrane. Starts out great measuring at 2 or 4 ppm but that doesn't last and the membrane is quickly fouled. My first membrane puts out 4 ppm TDS. Based on advice from BRS, I tried reseating the second membrane. Nope, doesn't work. Swapping out the RO tubing making the second membrane the first and the first membrane the second doesn't work either. It runs 28 ppm TDS with the flush valve open. That just proves the membrane is fouled. My HM Digital TDS triple in line meter is new and installed correctly. Also have a Hanna hand held. So there's really no way for the first membrane to continue to work great and the second membrane to fail so soon except for the fact that your feeding it highly concentrated waste water from the first membrane? Right?
BRS says this works for them long term and that their TDS from their second membrane runs about 7 ppm. I spoke with them Friday regarding troubleshooting. I'd love for this to work, but I can't see trying this with a 3rd membrane unless someone can tell me what I'm doing wrong.
Anyone have any thoughts? Does this work for you? What's different about my set up? Does this not work for you also?
