I have been mixing to the 20 gallon recipe, in my 32 gallon Brute. Once the ESV is all dissolved, I will put in another type of salt (lately Brightwell, Red Sea CP or RC) to get the entire batch up to 35ppt.
This way I don't need to be too precise w/ the ESV, and the bulk of the batch is ESV. I have always been blending at least 2 different salts. This will avoid any possible batch problems w/in a single manufacturer and possibly even out any Mg or Ca issues that might be specific to a single salt.
