We are having the same issue in out other bathtub. It's just the two of us, so we hardly ever use other other tub and only noticed our whirlpool tub. I started checking it more often, and it's essentially the same story - Max sustained hot water flow is under 3gpm as well.
Last edited by apewrangler; 12-04-2015 at 01:02 PM.
Reason: add info