We will be installing wells for vertical closed loops. Our location is about 400' from a lake and the water table is about 4' below grade. I am expecting the well to be full of water at all times. The soil is very sandy as well, so I would be surprised to see the wells maintain a low water level. Is there a thermal advantage to still use grout even if the well will be full of water? Can we pass on the grout and if there is an issue perform grouting at a later date?