I ave a in ground 12k gal salt water pool. The city I live in has extremely hard water. Because of this I have to clean my SWG every 1-2 months due to scaling. Recently it was cleaned and after doing so my ppm ranges from 3000-3200. However within a week my ppm has dropped to 2300 and my check salt level alert light has been activated. I have added 2 bags of salt over the last 2 weeks where the ppm raised to 2800, but a week later (today) the level has again dropped to 2200. Any ideas?? thx