I recently purchased a SWG for my pool. I bought enough salt at the store to bring the levels up to 3500ppm. I now just installed a water softener that is the source of the autofill for the pool. Now that it's 2 weeks since I installed the softener, the SWG (Intellichlor IC40) is showing the salt levels are high.
I did some research and found that on average for my area (17 grains of hardness), the softener puts in 100 milligrams of sodium/quart of water to soften it. Another site says that 1 ppm is about 1 milligram/liter. Since 1 liter is barely more than a 1 quart, 1 ppm ~= milligram/quart. I estimate my pool looses about 8 gallons a day (450sq ft in Phoenix). 8 * 4 = 24 quarts * 100 milligram/quart = 240 ppm added to the pool per day. So if my pool starts out at 3500 ppm, after about 10 days it should be close to 6000ppm, which is the limit I've read in other threads that one does not want the pool to get to.
Is my conversion right? I would have figured that if this "salt level creep" was this fast, others would be discussing it here. The only metal I have in my pool is the light.
I'm glad to keep the CH in check for my pool now, but I may have traded one problem for another. It's not going to be easy to run a pipe from the front of the house all the way back to the pool autofill to bypass the softener.