I just installed a SWG this year, the first of may. we added the recommended amount of salt, and within 48 hours the salt level was at 2400 where it remained until last weekend. so, from the first of may until the last week of July, all of my chemicals were perfect! Last week, the salt level had dropped to 2300, so it was not generating chlorine efficiently. I added 80 lb of salt, the following day the salt level was at 2100ppm, so I added 120 lbs. the following day the level was at 2700, and the system was generating chlorine. 4 days later, the salt level is down to 2000, once again, not generating chlorine. I plan to add more salt today, but from what I have read, adding salt like this seems unusual....what do you think?

That does seem unusual. How are you testing your salt level?

Well I guess the question is how big is your pool? Just a guess a 18000 gallons would take 482lbs of salt to bring your level 3200. So how mich did you start with?

The SWG has a display, which is what displays, as of yesterday, 2000, I also purchased some test strips, (I thought there might be something wrong with the display on the unit). the pool is almost 30,000 gallons and I started with 800 lbs of salt

I am interested to see what the experts say. I didn't know salt could deplete without water change.

Is the CYA level constant? How about the CH?

Scott

have you had lots of rains lately in your area?

alternatively, does your pool have auto top up? if so - you might have a leak, but you aren't seeing it because it keeps topping up.
disable auto top up and see if the level drops over few days

Test strips are not very accurate. Evaporation will not cause that much of a swing. Backwashing or splash out are losses of salt.