after installing a new hot water heater, when the faucet is turned on there is a gurgling that occurs when the hot water kicks in. we have had the plumber back twice, first they replaced the magnesium rods (did not react well with the well water) with aluminum pipes (it is a BOCK HEATER); then after checking everything the only thing they could come up with is to reduce the heat of the water from 135 to 120. It did improve, but the gurgling, though not as loud still exists.........more dominant in one bathroom.........i would appreciate any thoughts on this.............