I
highly recommend CHC ,moving all my Meyer citrus into CHC mix was the best ideea for 2010 . My trees are just doing very well.
But his is not the problem you have , I guess the tree is used to get a lot of food being in the nursery and once you take him home you don't fertilize him so often as it used to be or you should.
Also place him in a partial shade and not in the full sun, and let the soil to dry a little on the surface , the soil is saturated with water/
Good Luck