Changing salt brand, new corals

[gregbenner]

I’m new to reefing, 8 months. I have been using the LFS for water changes every two weeks, 20 gallons each time for my 150 gallon tank. I’ve just added a Kamoer automatic water changing/top off system, and will be using tropic Marin pro salt, and am unaware of what brand the LFS used (don’t really want to ask yet). From numerous posts on this forum, I realize that changing brands of salt can be stressful to the corals and the fish, and I plan on only changing 6 L per day to start.
It makes sense why a change in salt could be stressful, so my question is that anytime I buy corals or fish from someone else there’s a high likelihood. I am changing the salt conditions from wherever it came from to my tank. Wouldn’t this be at least as stressful, or is it just the risk we take, keeping in mind it’s not the whole tank?

 

[GARRIGA]

No clue if there's actual shock from differences in calcium, magnesium and trace levels but it's never made sense to me that changing salt brands mattered if salinity, temp, alkalinity and pH were comparable. Were that the case. Anything caught and moved through the various hands wouldn't survive. Each likely using the most affordable and obtainable to their locality.