Pool was built in 2020. I’ve had ongoing issues with the hot tub heater squealing - they say it gets enough gas so that leads me to believe it isn’t getting enough water flow. Filter is regularly backwashed and opened up and cleaned out a little less than a year ago. The backflow handle was getting hard to turn and now today it was leaking water. The pool service guys are saying $650 to replace the multiport valve. 1) does that sound right and 2) should that go bad in less than 4 years??