Anode rod after 6 years

[Mikey]

I have well water, chlorinated, filtered through Centaur carbon, then softened. Solar heater, so electric backup is seldom used, temperature usually around 160°F at the kitchen sink. I flush the water heater annually, and usually see a bunch of white crystals. I pulled the anode rod to see how it was doing, and found the following:



The rod is aluminum, 5/8" x 42" and seems unaffected by whatever's going on in the (80 gallon) water heater, but it's breeding the white crystals. They're obviously not water soluble; bigger chunks rub off the rod easily, but the underlying layer is on there pretty solid. It tastes chalky, so I'm guessing CaCO3, but wondering why that would be in the softened water.

So, questions are:

1) What are these crystals?

2) Do they affect the functioning of the anode rod? Should I remove them from the anode rod before replacing it?

 

[Reach4]

I wonder if it is aluminum oxide. Seeing how it reacts to vinegar or CLR could distinguish, I think. If it scrapes off easily, I would remove it. Searching around I saw people saying that aluminum oxide settles to the bottom of the tank, and that is one of the reasons for flushing the tank. Maybe while you can spray a hose or even pressure washer spray into the top, it might be worth flushing. I used phosphoric acid and laundry detergent to remove the long accumulation of stuff in the tank before I put in the filtration.

Your rod has steel in the middle, but it sounds like you are nowhere near the steel yet. My magnesium rod was down to the steel (used house), so I put in a powered anode.. almost $250 with shipping. At the time I ordered it, I was thinking of sulfur. However my Centaur Carbon filter solved that along with the iron, so another magnesium rod might have made sense for me. I am maybe a still little cautious about aluminum in drinking water still, but the bad statements seem to have died out. I guess I don't drink my heated water, so that should not be a worry. Anyway, I envision moving my powered anode to my next heater.

 

[Sponsor]

 

[Mikey]

I hadn't thought of that. Aluminum oxide is typically very hard, but this stuff is kind of crumbly.

There's no indication that the underlying aluminum rod is sacrificing anything. It's just accreting these crumbly gobs of whatever.

No real reaction to vinegar that I can see. Time to dig out my college chemistry notes.

 

[Dj2]

Dip it in a bath of vinegar for at least six hours, then see if there's a change.

 

[SteveW]

A resource I've used for a while is waterheaterrescue (you know the rest of the URL).

The guy who runs the site sells anodes and other accessories and a book he wrote, and he believes that with proper care a WH can live for 20 years.

 

[Mikey]

dj2, sorry, I got bored after a couple of hours and put the rod back in the heater. I had put a tablespoon or so of the stuff in a beaker with some vinegar and the mixture turned cloudy, but it wasn't clear if anything was being dissolved, if a reaction was going on, or if there was just a suspension of fine particulate matter.

SteveW, I've been on that site in the past, have his (excellent) book, and just posted a request there similar to the one I did here.

Reach4, I've been considering a powered anode ever since I bought this aluminum one. I'm not concerned about smell (the aluminum rod seems to be doing OK in that department), but if I can get 20+ years out of the tank, I'll be a happy camper. Also dead camper by then, probably, but I'm sure the next owner will appreciate it. I'd like to power the anode with the same PV array that powers the circulating pump, so I've asked about that in my post as well.

 

[hj]

quoter; if I can get 20+ years out of the tank,

Good luck with that, but if you do it will have more to do with the quality of your water than the anode rod. You may get 20 years with that anode rod, but only 240 months if you do nothing.

 

[DonL]

quoter; if I can get 20+ years out of the tank,

Good luck with that, but if you do it will have more to do with the quality of your water than the anode rod. You may get 20 years with that anode rod, but only 240 months if you do nothing.

lol

That is about right.