I had the same problem
I also had a bad smell from my hot water tank and black grainey stuff coming out of the taps. I also changed the anod rod to an aluminum one also and still didnt help. what did help was to turn up the temperature on the tank by 20 degrees and it disappeared in 1 day. It is going on one week and all is fine. good luck.We’ve been in the house over 20 years. We have a conditioner due to high iron in the well water. We never had an odor problem before.
In August we had a Geothermal Heating system installed and second 80-gallon hot water tank that pre-heats our hot water by the output of our air conditioner. We started noticing an odor in out hot water in January and had our conditioner checked. By May the odor was really bad and we drained the bottom of the hot water tanks and what came out was literally black! We changed the anode rod in the electric tank but that did not solve the problem.
This past weekend we chlorinated the well and that has solved the problem (so far). Of course we have no idea how long that will last.
Our plumber is recommending a $1,200 UV light system that needs to be serviced every year. I think this is overkill!
Is there any type of manual chlorine injection system that we can mount at the input to our dual hot water tanks? My thought is to chlorinate the hot water tanks manually every so often, maybe twice a year if necessary, but I’d like to do it without having to open up the tanks in any way.
Anyone have any thoughts on this?