I also use Red Sea Coral Pro but have found it to have a low DKH around 7. I mix it at 77.5 degrees and have it circulating each week for 24 hours before usage. PH is around 8.1, bucket is clean and water is distilled and checked with tds meter before use.
I will continue to use this salt until I am out and then I am going back to viaaqua -
OceanPure Sea Salt - 50 Gallon Mix Bag (Saltwater Aquarium Supplies > Salt Mix )
Excellent salt, Excellent price, no problems