I have the same problem, its co2 in the well water. The easiest way to fix this is- undo the line coming out of the membrane, the good water line that feeds your di resin chamber. Run this line into a container and put in a airstone to airate the water(24hrs). Then use a small cheap pump to pump the water intp your di resin chamber. This should take care of your problem, dont throw away your old resin, just let it sit out in a pan or bowl for a day or so, keep moist and it will recharge itself if was exhausted from co2.