I don't use salt at home, but at my store we get new fish weekly, thus stressed fish weekly. I find for stressed fish it helps them stay alive longer. The store keeps the tanks at .02% salinty, and when I say losses I mean more dead fish than usual in the tanks, which are all on the same system. Salt is added daily to keep it at .02% because the system (2500gallons) is cleaned via drip system. Nitrates never get above 30-40.
You are correct, there is little alkalinity in our water, and we have trouble buffering it.
where do u work if i may ask?