flycatchers Posted July 7, 2013 Report Share Posted July 7, 2013 I replaced my membrane last year and also replaced the two filters and DI resine in August. During the winter I tend to run the system about once a week and run off a couple of gallons. By spring the TDS had risen to 35 so I replaced both filters and resin and it took me to about 1 or 2. With the increased dry weather I have been running the system several days most weeks. When I checked the TDS today it was 75! Still lower than my very hard water of over 300, but rising far quicker than expected. Any ideas? The pressure gauge shows 45psi when in use. Quote Link to comment Share on other sites More sharing options...
Richard Bunn Posted July 7, 2013 Report Share Posted July 7, 2013 No ideas but as long as it's <150 you're fine. Quote Link to comment Share on other sites More sharing options...
flycatchers Posted July 11, 2013 Author Report Share Posted July 11, 2013 I wonder if I should get a whole new RO unit next time rather than just new filters & or membrane? The TDS is now 85 and rising. Still far lower than tap water but surely it should stay at a much lower level with a 6 month old membrane and filters/resin just replace two months ago? Quote Link to comment Share on other sites More sharing options...
billynomates666 Posted July 12, 2013 Report Share Posted July 12, 2013 Is it possible that the water is passing the membrane seal? Cheers Steve Quote Link to comment Share on other sites More sharing options...
flycatchers Posted July 17, 2013 Author Report Share Posted July 17, 2013 Is it possible that the water is passing the membrane seal? Cheers Steve How could I check that do you think? I replaced the DI Resin again today as it was up to 95. Just checked it again and its up to 160!! Not impressed by the RO system if it only gives any usable TDS for about 3 months!! Thankfully got a bit of rain water left as I mainly used the RO water on my Heli etc. But now it is more likely to do more harm than good to those plants! cheers bill Quote Link to comment Share on other sites More sharing options...
Blocky71 Posted July 23, 2013 Report Share Posted July 23, 2013 It does sound like there's a faulty seal or something if you're not manufacturing large amounts of ro water. My unit has a "1500 gallon" life, I'm guessing by the time I've passed that much tap water through it the readings will be heading upwards. 1500 gallons or 6819 ltrs roughly would take me around 68 days of continual running from my tap pressure, you mentioned 45psi pressure?. I take it your system has a pump?. Maybe you are just producing a lot more than you think?, with a pump on mine it would exceed the filters expectations in 34 days according to my rough calculations. That is a fair bit of water though ;-) Quote Link to comment Share on other sites More sharing options...
flycatchers Posted July 23, 2013 Author Report Share Posted July 23, 2013 It might be overuse but it seemed to start rising after replacing the filters again quite quickly. I use a pump and that gives 80psi. I had considered getting another RO unit similar to yours as it might be getting gummed up as the overall setup is now 4 years old. But with new filters, membrane & flow restrictor this year. Interesting enough when trying out my TDS meter- most rain water butts give an average of 35. The ones fed from the garage roof are 55 one side and 125 the other!! Though that side does collect loads of leaves as well! Quote Link to comment Share on other sites More sharing options...
Blocky71 Posted July 23, 2013 Report Share Posted July 23, 2013 Blimey, I'm out of my depth lol ! Quote Link to comment Share on other sites More sharing options...
mobile Posted July 23, 2013 Report Share Posted July 23, 2013 Sounds like some water is bypassing the RO membrane and the DI resin is having to do the work. With the small quantities of resin in typical RO systems, it would soon get exhausted. If possible, it might be a idea to check the RO product water prior to it entering the DI resin canister to see if the membrane is working, or alternatively remove the resin and check the output. Quote Link to comment Share on other sites More sharing options...
flycatchers Posted July 23, 2013 Author Report Share Posted July 23, 2013 The output directly from the membrane is roughly the same as from the DI resin filter. Now about 125. Quote Link to comment Share on other sites More sharing options...
Simon Lumb Posted July 25, 2013 Report Share Posted July 25, 2013 Bill the fact that your rain water gives a reading of 55 and 135 depending upon where you collect says to me, whats the big deal? Far too much science and over analysis with CP growing if you ask me. S Quote Link to comment Share on other sites More sharing options...
flycatchers Posted July 25, 2013 Author Report Share Posted July 25, 2013 I think that is right Simon. Indeed I wonder whether 0 or a very low TDS is almost too pure for the plants! In the wild they would always have some impurities in their water. Quote Link to comment Share on other sites More sharing options...
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