[fishytime]

Originally Posted by Delphinus

THAT's interesting (although I think it's technically a "loo" believe it or not). Anyhow of course what happens when that happens is there will be a dip in pressure in your lines but I wouldn't have guessed it would cause TDS to dip as well. I've never tried measuring TDS on the inlet side of my RO/DI so I can't try this myself. I have my "inlet" side after the RO, and my "outlet" side after the DI. So I have no idea what the incoming TDS is (I just know it sucks like 150-250), but the nice thing about setting it up this way is that I can tell when it's time to change the RO membrane and I can tell when it's time to change the DI (even though the colour change ought to be good enough for that I suppose). Also I know when it's OK to stop flushing the membrane (post-RO reading starts off at 90ish usually, and I switch the flush valve over when it drops below 10. It takes a lot longer than I thought it would. Before I had one I would just flush the membrane for like 30 seconds to a minute, since getting the dual meter I learned it's more like 5 minutes minimum..).

Ya, wouldnt a drop in pressure mean a longer contact time with the sensor dewhickey thing?.....you would think that the "in" TDS would be higher???......wow you do lots o stuff with your RO Tony......I havnt done a thing (flush/change membranes) for a year and it still reading 0 you obviously use it way more than I do(before 45g in two weeks, now 50g in two weeks)