Hot water is coming out of all faucets brown
Definitely get a plumber out. Sounds like the water heater is dying. Either scale build-up dropped off the tank side, tank surface rust gets weaker as it gets thicker &amp; accumulated mineral deposits will peel off in large pieces. Or, your anode rod was so eaten away that a piece fell off of that. Items dropping in the tank stirs up the tank's bottom sediments.

The Aquatherm can contribute since it has metals, but that didn't cause it. The water heater just wasn't serviced &amp; therefore assessed every year or 2. Run the hot water for 10 or more minutes, like taking a shower, to see if it clears up at all. Use the bath tub (if you have one) not the shower or a sink that you can get the aerator off (the tub doesn't have one) of so you won't have to take it off later for unclogging.

Yikes, I haven't heard of a direct or power vent 50-gallon water heater costing that much before installation costs. Yeah, $1350 &amp; that's still right in line now with the home improvement stores...Maybe you do have a specially shaped water heater or the contractor owns the market &amp; is taking advantage.