That explains a lot. My water pressure is low. I've looked at buying a booster pump but the ones I've found are very expensive. Anyone know where I can buy one at a reasonable price?
I do have a flush kit on the unit but I haven't allowed the water to run after I've flushed. I also don't really rinse the tubes that well.
That would explain why my readings are high.
When I bought my RO unit, I knew nothing and hoped it was just a matter of plugging it in and letting 'er rip. Like everything in the hobby though, it's never that simple and usually involves complex, expensive solutions.
From what I know, I think most membranes flush as they make water. I haven't really seen or heard many people recommending flush kits. I don't think they're bad at all, I just think they probably don't have as much of a benefit as people think.
Also your readings don't sound normal, but that would depend on your input water. What's the TDS of your input water? With that, you can then calculate how efficiently your membrane is working. Let the unit run for a bit before calculating output water though. You get what's called TDS creep when firing it up. I don't think the cleanliness with your RO unit or filter housings have an appreciable effect on TDS.
I think you have the same problem as me. water pressure, water pressure,
, water pressure,
. Most membranes are rated at 96-98% efficiency. My water pressure is just shy of 40 PSI. My input water is 550 TDS, output is 50 TDS. If you crunch the numbers, that's 89% efficiency. I think both your and my situations, a booster pump would solve most of the problems. Higher water pressure would lead to a more efficienct membrane performance and increased water production. You can tweak things to raise the performance a bit (a better membrane etc.) but you won't have much luck without a booster pump.
I looked around on eBay for awhile, and I found an aquatec 8800 for about $110 shipped. They have some cheaper units that range from $75 shipped to $95 shipped, but they all looked a bit sketchy. Everyone recommends the aquatec pump. Being a college student, I nearly exceeded my aquarium budget already by buying the RODI, but the aquatec may become my next investment. The best way is to charge it on CC at the beginning of your statement period, and you have 30 days to relax and not look at the bill before curling into a ball and crying.
But seriously, for low water pressure, a booster pump is about the only viable option to fix membrane performance.