Hot water suddenly went to half flow to tub in master bedroom. Reduced flow to tub for kids also. Third tub, downstairs, is fine, it's rarely used.
Showers, and all other taps are normal flow. Kids bath is tub shower combo. The master bathtub, which is a whirlpool tub, is separate from the shower. This tub also has a shower head, of which the flow is normal.
The problem is the two tubs, hot water side only.
Could something be clogged in both cartridge s?
Incoming water temp, to the house, is 36-40°f.