Hello as you know I'm collecting the necessities for wfp. I will start with di filtering only due to that ro membranes are just so expensive and wont use it very much yet. Now I've been playing with my tds meter and have tested lots of random things in and around the house as you do I worked out that the water filter we use for our drinking water (one of those active carbon filtering thingies you fill up from the top and it slowly runs through) almost halfs my tds. Thats good news!! I know you can buy the 10" filter housings and fit different filters, and before a RO if i understand correctly you have 3 filters. A 5micron filter, a 1 micron filter and a carbon filter.(please correct me if wrong) Now my question is(finally) if i would use those 3 filters who are relatively cheap(£30-40 for it all) would that reduce my tds, now around 130 and make my resin last a lot longer? or is it a waste of money and space it only benefits if i actually have a RO? Anybody who would just like to test with his TDS meter at all stages of his RO unit what the reading are? (bit of a big task sorry) Thank you all, I hope this kind of makes sense.