The only secret to the salt you use is picking one that is as close to the parameters to where you keep your system as possible and mixes clean. I used to love the Live Aquaria salt, it mixed up nearly identical to where I keep my tank and was a very clean salt. No brown buildup or precip.
Fritz mixes pretty clean but like billyocean parameters bounced around and would precip a little. Even though they rate the mix very similar to LA's salt. We tried working with Fritz to find a solution to the salt solution. I was told their salt was best mixed at 68 degrees. Try to keep 250+ gallons at 68 degrees in Georgia. Maybe this time of year in the few winter true winter months we have. I did hook up a chiller to my 300 gallon mixing barrel and it did help but was just too much of a PITA to do long term. I mix batches by the full box and can't be doing that every time.
AF salt mixes just about as clean as LA and also has close parameters to what I like. I also like that you can look up their lot codes and get an ICP-OES report on each batch. Haven't seen that with other manufactures.
In the end I'm always open to looking at something different if the parameters are close to what I want and it's cost effective.