I'm sure I'm changing my resin to often. Does anyone know how much water can be produced b4 pre-filters and resin need changing in a high tds area [about 320ppm at the tap] I changed all including membrane 2nd week in August on a 4040 sysem started getting ppm creep couple of weeks ago so changed the 20" pre filters and the 25k resin now keeping a record of the quantity produced and fitted 2 dual in-line tds meters for what they are worth to help me monitor readings. As a side note I purchased calibration fluid, every sensor gave different reading including my handheld I found it impossible to calibrate handheld and gave up on the others just got them as close as I could ie within 20ppm. Has anyone else tried to calibrate HM tds2?
Fiberdyne 20" carbon block from Gardiners needs changing after 78,000 liters of water processed = pure and waste. Buy an inline water meter and install somewhere before the r/o inlet ( either side of the prefilters) and monitor it.
R/o membranes should be working at between 96 and 98% efficiency. So rejection rate after pure should be between 6 & 13ppm.
If you have a genuine tds meter there should be no reason why you can't adjust it accurately. I've done mine using calibration fluid. Never bothered with adjusting tds in inline tds meter as it was accurate when fitted.