Instant Ocean- been working well for me. I do use a pump to circulate the water in the rubbermaid tub for about half hour before adding to tank. Do this mostly to give me time to scrape algae, work on a FW tank, etc. My corals (all soft) don't seem to mind it.
1) you can't/shouldn't use "aquarium salt" for marine/brackish applicaitons
2) for freshwater applications, canning/pickling salt works just as good, and is MUCH cheaper.
I use red sea pro or NEO marine by Brightwell on the smaller frag tanks (saves me dosing but is pricey). I use Instant Ocean 200G boxes for the larger main system (gets regular dosing).
Instant ocean is the cheapest here in WI, and for the price I dont think it can be beat. Reefing for almost 9 years and I have never used anything other than reef crystals by IO