that's a different looking reef crystals than the one i buy, but if it's the same thing/different package from what i'm told it's the high quality stuff.
I usually dump about 5 cups of salt in 5 gallons of water, test it, add more. But i have an endless supply of RO. I've never gone over though.
If you want to, test it after each cup... it's easy with your refractometer and uses basically no water.