hot water slow in bath but fast in other places

My bet is that you don't flush, not drain. your water heater you've allowed mineral build in your heater and now it's in your system clogging the inputs of your cartridges. Shut the water band open up the valves affected. Remove the cartridges and check and clean the input ports. Now place a pan over the op[en valve and turn the water back on to flush out the supplies. Reassemble and test.
So this doesn't happen again here's how to keep your heater clean.


For long life and fewer troubles you should keep your heater clear of mineral build-up by FLUSHING NOT DRAINING on a regular schedule.

Attach a hose to the boiler drain at the bottom of the tank. With the pressure on, open the boiler drain and let it run untill the water runs clear. You will see a spurt of red,(rust) followed by white or yellow grains,(lime or calcium carbonate). This shouldn't take more then a few minutes.

Do this monthly to keep it clear. Now flush out your hot water lines on ALL fixtures that are affected . Now pull each aerator and clean the screens. Be sure you put them back together the same way you took them out. Don't forget to flush it out every month. Your heater will thank you for it. Hope this helps and thank you for rating my answer,

Tom