GEEEEEEEEEEES doug, i'm a window cleaner!
You're right, for one i am certainley not scientific enough to analise all that info
I can't specificaly tell you how many litres of water i purify with one bag of resin etc. What i can say is that my findings are correct with my situation as i also have tried many things to reduce my resin costs without sacrificing water quality. As stated, i use much more water now than i did two years ago but less than half the resin! My tap tds is 76ppm (recentley dropped from 96ppm)
1. purolite- when this resin hits 001ppm there is generaly no stopping it just rising by the minute & in no time, usualy a day or two at the most is un-usable for window cleaning i.e. tds= 20/30/40 etc.
2. When this happens with dowex 001ppm will stay at 001ppm all week & only start rising slowley, a quick shake of the vessel ( performed in the correct way) will put the reading back to 000ppm. Obviousely it will rise again & the periods of time at 000ppm get less & less & so this is when i switch vessels round.
3. with either of these resins the higher the flow the less efficient they become, i.e. if say i have a reading of 001ppm & i then run water through at full mains pressure the reading will start to shoot up. I tried it with a 000ppm reading too & found the tds starting to rise but slow the flow back to normal & hey presto- 000ppm again.
4. With purolite i could never get more than 4 weeks out of a 3/4 fill of 2- 11Ltr DI's, but with dowex i can get 7/8/9 weeks & i'm using more water now.
Dave @ st ives
You havent answered the most important aspect of this topic yet mate- have you run your di's at only a low flow rate to steadily fill your tanks- or have you always filled at full tap pressure- 600lph? as i'm pretty sure this is having a big affect on your resin economy but i can't seem to get it out of you
Tony