Pool and Spa
Questions about Pool Repair? Ask an Expert Online.
When salt cells start to age out they "think" the salt level is actually lower than what it really is. I would recommend you take the water to a professional that uses a meter to test the salt level and see what the salt level really is. Many times we find salt levels at over 5,000ppm but the cell has aged (still works) and is need of replacement. What we usually do to limp through the end of year is to increase the % level of chlorine as opposed to adding more salt.
IF the salt tests where it should than you are having a dilution event. This could be either from a slide that is attached to a water hose, or you have a leak in the pool. But at 3 years old and if your pool is 25,000 gallons to 40,000 gallons it's about time to replace the cell.
I hope this has helped you and if I can help further please let me know.
The first step is to rule out the cell aging or the board by having the water tested to compare the salt levels to be sure the salt IS actually low. That way if it is, you may still be looking at a leak.