Sorry Guys: I didn't explain myself very well. My point was: A residence is normally fed from the meter with either 1 or 3/4in cold water line, dropping down to 3/4in to feed hot & cold EQUALLY around the house. A fully open 3/4in line at 40psi will allow somewhere in the region of 25-30gpm to flow. A filling toilet tank, fills at the rate of about 3gpm, a washing machine takes about 4gpm and a bath tub faucet, on average, dumps about 5-6gpm. Do you see what I'm saying: If the hot & cold water pressure & flow is equal at all points in the home, then a scalding situation should not exist. Ergo,(I think) my contention that either a (restrictive) water softener/filter, a scaled up valve or plumbing, or a stopped up shower head, or maybe the recirc pump is in the wrong part of the loop. It should be plumbed in the RETURN line of the loop, back at the tank. Why? impellers restrict flow, especially if they are scaled up. The doo-dad which fits in the shower head only masks the problem. A company called Evis pioneered the use of magnetic water conditioning, back in the 50s and their systems are still working. I have personally de-scaled homes, businesses, power stations, ships and cooling towers with magnets, they've been around a long time. I don't mean to butt heads guys, but my advice is based on lots of experience. Magnets are here to stay, and I'll send you the information if you want it. E-mail me. email@example.com or 800 851 9891. Cheers, Brian. (sorry about the minor spam).