Greenish sludgy stuff in water heater tank

**BobW44** · 07-03-2009, 07:05 AM

Hi all, Great forum, lot's of knowledgeble info floating around. It has helped me a great deal in my homeowner maintenance quests.
Well, today I drained the tank to replace the gas control valve. While I had the tank drained, I decided to replace the anode rod. Of course, I shut off the natural gas, water supply, and electric before I got started.

After draining the water tank, I removed the anode rod. All that was left was a bare wire. Glad I decided to check it.

After removing the gas valve, which also threads into the tank for the thermistor, I noticed quite a bit of greenish sludge in the tank. It had the consistency of whipped cream, light and flluffy. There appears to be quite a lot of it in the tank. It even was all over the thermistor probe.

What's is this stuff and how do I remove it?

**kingsotall** · 07-03-2009, 02:00 PM

Sounds like sediment. Most times it is not rock hard material but soft and almost slimy. Bluish green color. Need to flush the tank.

**BobW44** · 07-03-2009, 02:46 PM

Thanks, A Wet-N-Dry Vacuum and numerous flushes pretty much cleaned it out.

After cleaning, I aimed a flashlight down the anode-rod-hole to illuminate the bottom of the tank as I looked in through hole at the bottom. Lo and behold, the old anode rod (or what was left of it) is lying on the bottom. I guess it dislodged from the wire-core as it aged. I tried to remove it but it was too difficult, (since I was working through the 1" hole)

Is this old anode rod ok to just lie on the bottom of the tank? I hope so.

Anyway, I installed the gas valve/thermostat, the new anode rod, and re-installed the blower. Reconnected the gas line, turned on the gas, and did a few snoop checks. Everything checked out, and I'm back in business.

**kingsotall** · 07-03-2009, 08:14 PM

One of these might have done the trick:

Good luck to ya.

hj · 07-04-2009, 07:48 AM

That sounds like what an old anode rod looks like before it becomes a bare wire. You probably scraped it off while removing the anode rod. A gas heater control does not have a thermistor, it has an Invar rod. But if you went to the trouble of completely disassembling the water heater, you would have been better off just replacing it.

**master plumber mark** · 07-04-2009, 03:44 PM

I have seen lots of the stuff you are talking about...

I have always wondered about it...

considering that this sludge has to boil and bubble to be able to heat the water....it sort of makes a stew.....

it makes me wonder if these sediments or heavy metals
that boil in the bottom of the heater could cause different skin diseases????

**Ladiesman271** · 07-06-2009, 11:45 AM

Tank water heaters end up being full of all sorts of crap and bacteria. That's why you are not supposed to ever use water from a water heater for cooking or for drinking.

Tankless water heaters are the way to go. At least they provide unlimited amounts of clean hot water.

hj · 07-10-2009, 06:15 AM

quote; Tankless water heaters are the way to go. At least they provide unlimited amounts of clean hot water.

The "stuff" on the bottom of water heaters is caused by heating it, so where do you suppose the "stuff" from a tankless heater ends up?

**Redwood** · 07-10-2009, 11:44 AM

Originally Posted by hj

quote; Tankless water heaters are the way to go. At least they provide unlimited amounts of clean hot water.

The "stuff" on the bottom of water heaters is caused by heating it, so where do you suppose the "stuff" from a tankless heater ends up?

I think last time Laddyboy was asked that he disappeared for a 3 months...

**TedL** · 07-10-2009, 06:32 PM

Originally Posted by Ladiesman271

Tankless water heaters are the way to go. At least they provide unlimited amounts of clean hot water.

If that were true, they would be a much more compelling buy. But the truth is they provide a very limited amount of hot water, albeit for essentially...forever.

But if you routinely have more than one person showering at the same time, or doing anything that uses more than a trivial amount of hot water, there will be much disappointment.

**SewerRatz** · 07-10-2009, 08:16 PM

Originally Posted by TedL

If that were true, they would be a much more compelling buy. But the truth is they provide a very limited amount of hot water, albeit for essentially...forever.

But if you routinely have more than one person showering at the same time, or doing anything that uses more than a trivial amount of hot water, there will be much disappointment.

Unless you install the right sized unit or units to properly fit the demand of the house. I get way to many calls from people wanting the smallest advertised unit stating thats all the currently need. I try to explain to them that what if they get a house full of people and need all three showers to run at once. Or if he sells the home to a larger family.

**master plumber mark** · 07-11-2009, 08:36 AM

I hate to admit it, but ladyboy does have a point about
the sludge in the bottom of the heaters....

it is pretty nasty, and it makes me wonder exactly what is in that crap....

I wish I had my camera with me when we took out a number of extra nasty ones....
it looked like someone puked up green slime all over their driveway....
it took well over 10 minutes to wash it all off....
and the mess it makes in your truck when the load shifts,
can be a lot of fun ....

Actually, that is about the only positive thing I can
think of about the tankless heaters....

no one ever cares to flush and
service their water heaters becasue they are so troble free...

**Gary Slusser** · 07-11-2009, 06:01 PM

IMO most of it is scale from hard water and the fluffy pasty stuff off the anode rod.

Tankless water heaters have a minimum hardness level and many will have a water softener in front of them to meet the minimum hardness allowed.

Green is usually copper. Slimy is bacteria.

**master plumber mark** · 07-12-2009, 07:45 AM

Originally Posted by Gary Slusser

IMO most of it is scale from hard water and the fluffy pasty stuff off the anode rod.

Tankless water heaters have a minimum hardness level and many will have a water softener in front of them to meet the minimum hardness allowed.

Green is usually copper. Slimy is bacteria.

now the next thing that makes me wonder is.....

what kinds of bacteria???

I assume it is inert or it would have already caused an uproar decades ago....??

**Ladiesman271** · 07-12-2009, 08:19 AM

Originally Posted by TedL

If that were true, they would be a much more compelling buy. But the truth is they provide a very limited amount of hot water, albeit for essentially...forever.

But if you routinely have more than one person showering at the same time, or doing anything that uses more than a trivial amount of hot water, there will be much disappointment.

You guys should update your thinking. Two people taking a shower at the same time is not a good thing to do. You should also use a lower flow shower head than your use!

Instructional video of the volume of hot water that is required by code for two people taking a shower at the same time being demonstated by a few old school licensed plumbers