I have used Reef Crystals for the last three years in a four year old five foot 120 gallon mixed reef tank. The first year I used Instant Ocean.
I pour 12 gallons of water in a Rubbermaid Brute and then insert two Hagen powerheads, one 400 gph and the other 270 gph. I then take a 1/2 cup size measuring cup and pour fifteen of these in the swirling water for a total salt quantity of 7 1/2 cups of Reef Crystals. I put the lid on and wait until Saturday or Sunday to give the salt at least one day to mix. I have never had a problem with any mixing with Reef Crystals although I do not mix and store for more than three of four days.
I siphon out four gallons into each of three salt buckets and use the 400 gph powerhead to pump the replacement water back into the aquarium. I wipe out the inside of the Rubbermaid Brute with a white towel and do not see any quantifiable gook or discoloration on the towels.
One thing I think I may have noticed in the past was mixing for over seven days or longer could possibly lead to some residue on the bottom of the mixing container although I again cannot rember any quantifiable residue on my cleaning towels?
I think Reef Crystals is probably the best reef salt on the market for people like me who have to use tap water. Like I said before, I have used Reef Crystals for three years and nobody has complained in my tank.
I cannot think of a another "reef" salt with a chelator I would trust and I do not know if I need a "chelator" with my tap water or Instant Ocean would work just fine?
Is there anybody out there who thinks I would benefit by switching to Instant Ocean as I am on my last 200 gallon box of Reef Crystals and I am told I should use the following steps if I am going to switch to a different salt?
"For the 1st water change, use 90% of the old salt mix and 10% of the new salt mix. Everytime you do a water change, increase the amount of new salt by 10%. So the second water change would be 80% old salt mix and 20% of the new salt mix."
How do you do the math if you are going to switch and do not want to throw out a half of a 200 gallon box of Reef Crystals?