It's been a while since I mixed a batch of Mg for dosing. I have 5 gallon buckets of powder Mg Sulfate and powder Mg Chloride from BRS. When I opened the powder Mg Chloride bucket I discovered that the top layer is liquid. I imagine it's safe to use but I wonder if I should change the mixing ratio from the BRS recommended formula (3 cups powdered Mg Sulfate with 5 cups powdered Mg Chloride per gallon). I'm thinking that 1 cup of Mg chloride powder does not have the same concentration as 1 cup of liquified Mg chloride "powder". Thoughts?