so the OP got a used tank hopefully for free...........
by the time he replaces the anode, replaces the elements and cleans
the sludge out of the tank.....
Has he wondered where that sludge came from? Almost certinally from
the inside of the tank which is nearly rotted out:(
Now he has a old tank, thats less efficent than a new tank with high
So his tank has cost probably cost nearly as much as a brand new cheap
short warranty tank
its rust the glass lining isnt perfect and fails over time which is
why tanks leak.
the fact the anode is eroded away is another indicator that tank is
old and on its last legs.
I love reusing stuff and saving money but this one is a loser....
And I guess that's the real question. How much longer will one get
from a tank if they do check and replace the anode when it's needed?
It would seem to make sense to me too. I started doing it on my
current water heater which is about 6-7 years old now. The original
anode is about 1/2 gone now. While it seems to make sense and I've
seen lots of opinions, I haven't actually seen any tests or studies
done. Has anyone else?
Far too many variables to be able to do any meaningful tests --
differences in tanks, anode design, water, usage, etc., etc., etc., ...
Best one could do would be a test under a given set of controlled
conditions for a given tank design, but that would have virtually no
value outside that test environment...
If that were the case, then no one would be able to test and evaluate
much of anything. Yet tests are routinely done on a wide variety of
products, aren't they? Consumer Reports, for example, tests
everything from dish washers to paint. And all those depend on a
multitude of factors that can vary widely.
If some simple tests showed that anode monitoring and replacement made
a substantial difference in longevity in a few different tanks and
environments, that would be a lot more substantial that it does work,
as opposed to peoples opinions.
On Jun 10, 2:00?pm, firstname.lastname@example.org wrote:
I wonder if the anode rod really becomes important once the glass
lining has already failed somewhere?
most tank leaks I have had occur around fittings, at seams etc. never
saw one in the middle of a tank.
so my theory is the anode erodes, its erosion driven by everything in
the plumbing system, everywhere theres water.
then the glass lining fails, the anode already partially gone fails,
noted as thin wire laying loose in bottom of tank duiring disection...
then finally the tank leaks.
tanks are so cheap, new ones more efficent, most humans will only buy
one every 10 years or so while owning a home. so at most 5 or 6 tanks
for me stretching tanks life and perhaps creating leak at anode
connection just isnt worth the risk.
Today I tend to replace tank every 19 years or so before it fails.
that way I pick the time place and cost.
no christmas even blizzard thank you.
the small added cost is worth the bucks, for peace of mind and
I think you have cause and effect reversed here. It seems more likely
that the anode prevents corrosion at the fittings where the glass
doesn't coat. The anode wears out, the rust starts at the fittings,
and continues at the edge of the glass, causing it to flake off.
Replacing the anode prevents the rust, preventing the glass damage.
$10 anode vs $200 heater? Hmmm. Let me think.
Every wateh heater leak I've ever seen started as a small drip,
leaving plenty of time to replace at your convenience - if you keep an
eye out for the drips.
Again, the major cause of failure is corrosion. The anode largely
prevents corrosion as the anode corrodes instead. I'm sure that almost
noone replaces anodes, so a few years after it dissappears, the water
There's a reason they put them in in the first place.
The interesting question is whether checking and replacing the anode
beyond what the manufacturer put there really extends the life of the
tank and is worth it. One possibility is that making sure the anode
still has material left does significantly prolong the life. The
other possibility is that the anode size that is put there is
sufficient to prevent premature corrosion failure in most cases. By
that I mean it gets the tank to the service life where other failure
mechanisms become prevalent, so that even if you do replace it, it may
not buy you much more time, because the tank is likely to now fail
from another failure mode that the anode doesn't prevent.
But like I said in my previous post, I've seen lots of opinions on
this, but nothing really backed up with any test data or scientific
That's a different question than the one you asked which at least I
interpreted as for a given tank, and more importantly, a given
application (namely your own specific installation).
I think there's little doubt that sacrificial anodes have benefits in
As for the wide-range applicability of CR tests and CR testing
protocols, don't get me started on them (again)... :(
By the way, it's probably not aluminum, it's magnesuim. I once took
an old magnesium anode and filed off some dust. Then I put a torch to
the dust (outdoors in a safe place) and watched the fireworks. It
looked sort of like a sparkler.
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