I have water hammering in my pipes that I did'nt have before when i turn off any valve in my bathroom, I don't really want to tear out the wall to put an arrestor on. Pressure is 68 psi,checked expansion tank PSI and bladder is ok,pulled all valves apart and cleaned out found a lot of rocks, checked pipe straps and are tight and held pipes while holding them through the valve hole, one thing I noticed is the pressure on the hot at the tub in less than the shower (they are back to back so the pipes run up the same wall) and they are teed off the same line? could a partially plugged hot water line cause this, but it does it on hot or cold? Please help if been on it for 3 days. Thanks for any advise Kevin