Anode rod material and price?

[makethatkerdistick]

My local plumbing supply story sold me a $65 anode rod for my standard 40 gal. gas water heater. The rod contains an aluminum zinc alloy. I found cheaper ones online for about half that amount or less.
Am I getting something magical with the more expensive rod? If not, I'll return it and order online. I like to support my local store, but this seems a tad too expensive.

 

[Phog]

That's expensive, it's just a metal rod. $25

Also did you get an aluminum anode rod on purpose? Magnesium anode is what usually comes in water tanks from the factory, magnesium is less noble on the galvanic corrosion scale than aluminum or zinc and therefore can offer slightly better protection. Aluminum anodes are generally installed more in well-water systems than they are for city water. (magnesium anodes can exacerbate smells when there is high sulphur concentration in the well water).

By the way a common problem people run into with anode rods is overhead clearance. If you don't have a high ceiling offering plenty of space for maneuvering the rods in/out, consider a segmented anode.

 

[Sponsor]

 

[makethatkerdistick]

Thanks for your reply, phog! I returned the expensive rod today and will order a traditional magnesium one online.

 

[Don H]

I know this thread is over a year old but I just went to the local plumbing supply house and they tried to sell me a segmented magnesium rod for $150! I found what looks like the same segmented rod for $30. I didn't buy it.

I've always bought straight rods in the past and just had enough clearance but I got a new water heater a few years ago that doesn't have enough clearance. So now instead of selling me a rod for a reasonable price (I don't expect them to beat Amazon) they sold nothing.

 

[Dj2]

Very good story indeed. The moral of the story: educate yourself when shopping around or getting estimates, so they don't take you to the cleaners.

 

[Don H]

When installing the anode does it make a difference if you use teflon tape or pipe sealant on the threads?
Also which is better, magnesium or aluminum? The supply house said the WH came with an aluminum anode. This is on an A.O. Smith Electric 50 gal. WH on well water.

 

[Reach4]

When installing the anode does it make a difference if you use teflon tape or pipe sealant on the threads?

I used PTFE, but I think either or both would be good. You might worry that PTFE would insulate the interface, but no. The threads cut right through the PTFE, and provide electrical continuity. What I would do is to not torque the new anode to nearly as it came to you. I would go about 15 ft-lb. Watch for any signs of a leak, and try another 1/8 turn in that case. Not over-torquing would make it much easier if you had to change the anode again.

Also which is better, magnesium (Mg) or aluminum? The supply house said the WH came with an aluminum anode. This is on an A.O. Smith Electric 50 gal. WH on well water.

Magnesium is better at protecting the WH, but it is more reactive with sulfur bacteria to help produce H2S from sulfate from the water. Aluminum+zinc rods (what the "aluminum" rods are) are less helpful to the SRB. Some just replace the anode with a brass plug, and with some waters, the WH lasts maybe 10 years or so with no anode. In some waters, even with a working anode, you might only get 10 years. I expect 30 or more years myself, but I have low-corrosivity water. Plus I have a powered anode.

A powered anode can protect like Mg but not feed SRB. I think the one with the long electrode is going to protect better than one with a stubby anode. But $$$ vs $$ for stubby. For more thoughts on powered anodes, use the search box above or ask for more info.

 

[Don H]

Thanks for the reply. The old anode was probably 80% gone after 7 years when I pulled it.

Put a new one in today, I used an aluminum one since that's what my local hardware store had, cost was $40. I used pipe sealant since I seam to have better luck with it. I had to use an impact gun to get the old one out. Installed the new one not near as tight but defiantly more than 15 ft. lb.
Should be good for another 7 years!

 

[Reach4]

Should be good for another 7 years!

How long did your previous WH last, if you know? I think changing anodes is good. I suspect that having changed (or had changed) an anode on our WHs put us in the upper 5%.

Did you notice impressive stuff out of the WH drain? Many just run the water through a hose where the flushed stuff can't be observed, which is fine.