High GH is not a problem, compared to high KH. The plants need calcium and magnesium, which are the primary GH elements. Fish and invertibrates need calcium too. Unless you run into problems with some of the fish who have problems with high GH water, and I don't know what fish that would be, I wouldn't worry about it. The less you do to modify the properties of your tap water, the more likely you are to maintain a consistent quality of water in the tank, which is much more important.