Working in the medical field with water and various types of what we call dialysate which is a complex prescription with various sodium bicarb, calcium, potassium, and many other ingredients. We were discussing over mixing sodium bicarb so I was testing the theory of over mixing salt if the same effects can happen within salt. Well my conclusion is correct you can over mix salt. So I mixed up 5 gallons for an hr and let sit, I than mixed up another 5 gallons and continued to mix it for 48 hrs. The results were the same. Salinity was the same and all other levels. Such as cal, alk, mag, etc etc. So I than let them sit for a week wondering if levels would drop or evap out. I used the one 5 gal as a water can be but a month later the levels had dropped drastically. All had dropped to 6.2, mag was 1150, and cal was 350. It had a lid and a small power head to keep circulation. This was done with salinity. I usually mix 140 gal at a time and I use in about 2 months or less. Well every time I do a water change I always have to bring my alk, cal, mag, and potassium back up. I don't know if other salt brands do this as well but my 90 almost crashed yesterday. I came home to a frogspawn dead that I've have for 2 years. I checked alk and it was fine cause Its on a dosed. I checked cal and it was 300, mag was 1100. I was shocked to see this. Brought all levels back up over 5-6 hrs cause I didn't want to shock everything. So moral of the story don't mix salt and let sit for longer than a month. I do run a heater and a power head in my big salt tank but crazy to see that the levels drop this much over a period of time. Even being completely sealed.