I picked up a juvenile electric blue dempsey, and have had him alone in a 10 gallon tank for a few months, and now he has grown to about 2.5 inches. I purchased a 46 gallon tank and have had it up and running for about a month now. I've done weekly water changes on the new tank, and even though I use the same water source for both, I can't seem to get the GH over 2. The 10 gallon tank's GH is consistently 9. My question is (a) given that these fish are notoriously fragile at this size, is it better to leave him in the smaller tank untill he reaches a larger size, and (b) How can I raise the GH of the new tank?