Originally Posted by rdonnelly7
I just switched to IO and I think it takes about a 1/2 cup per gallon like it says. In any case, this is the first time I am using IO and I hate it. I usually use kent Marine and it is almost exactly 2 cups for every 5 gallons, less than IO. When I mix up 25 gallons of water it takes 5 scoops (cup I measure with) = 10 cups to get the salinty I wanted. I bought IO last time because they were out of kent. Now when I mix 5 scoop (10 cups) with IO on 25 gallons it only gets me to like 1.010, it takes like another 3 scoops to get to the salinty I want. So you get much more use out of Kent for the same price. I will never use IO again. Nothing wrong with it, but a waste of money in my opinion. I just focus on the cups to get me close, then I measure with a refractometer (hydrometers stink), and tweek it till I get my salinity.
I agree, I have nothing but problems with my calcium levels using IO. I now use Oceanic.