We have an old claw foot tub. We bought a new faucet that comes with a hand held shower. 10 years later, if you turn the hand held shower on, only Half of the water comes out. The other half of the water comes out of the faucet. Why doesn't the shower work full force anymore? How can I stop the water from coming out of the faucet at the same time? I am hoping the is just a gasket problem. Thank you, Kris