Stainless steel water tank

[JLL]

About 10 years ago I had a 150 gal stainless steel fresh water tank made for my Bus.  Soon after some guy in a RV parts store told me that it wont last two years.  Last year my water started to look rusty.  I soon that cleared up. Then my surflow pump quit working,  so I put a new one on.  Soon the new one quit. So I opend it up and found it pluged up with black grit about the consistency of suger.  I have since put filter on going into the pump and that took care of the problem althogh the filter collects a lot of the grit I can work around that. 
I was wondering if any of you have had any experience with SS tanks.  Good or bad?

JLL

[bevans6]

article on corrosion in stainless steel water tanks:

http://www.corrosion-doctors.org/MatSelect/rouging.htm

Also, the water from my well, if not filtered, contains enough iron sediment to cause the problem you have with a perfect tank over 10 years just from putting the water in it.  It may not be a tank failure or issue at all, it may just be the water.

Brian

[txjeff]

I noticed rust in my water from the stainless steel tank also, when I pulled the water level sensors I found the bolts they used had rusted to a big blob. I removed the sensors and plugged the holes and everything has been good since.

jeff

[Chaz]

I can't imagine what would do that. I work in s.s. about everyday but not in the tank building industry.
I wouldn't think the grade of stainless would matter as I would hope it is at least 304. And if they TIG'ed it up with a comperable s.s. filler rod, I'd think it would last till the cows come home!

That said, s.s. will still rust. (ie. stain-less) And if you plasma cut, heat or weld it, the heat effected area will bring the free carbon to the surface and that will rust. It needs to be passivated to get rid of the carbon.

The "black sugar" might be some sort of chemical reaction. But I don't know how it could be with the s.s.

This is interesting.
 Chaz

[Don4107]

First bus has stainless tank fresh water tank.  Getting close to 20 years old.  No problems.

Don 4107

[eddiepotts]

Just a thought and I have no idea if it would work or the cost but, could you have it chromed. Plus it would really look cool you would never have to worry about what kind of water you put in it.

[rusty]

I disinfect my stainless steel tanks at least once a year and use chlorine. One time after I did that a reddish water came out of the tank. From the corrosion link it looks like I got carried away with the chlorine. Thank you for clearing that up.

Wayne

[Chaz]

Altho it's an oxidizer, you might think about 35% food grade hydrogen peroxide for disinfection. It's better on many levels. Just don't get it on you.

[kyle4501]

Proper passivation of your stainless tank followed by care in what you put in it should eliminate future problems.

Obviously excessive chlorine & iron should be avoided.


In my opinion, stainless is a superior material for tanks, but it is not perfect or infallible. Plastic is good enough for most, but it too has it's own issues & peculiarities.

BTW, I wouldn't put too much stock in what "some guy in a RV parts store" said about stainless tanks not lasting. We use stainless tanks in industry - if plastic was better, we'd use that instead. 

[luvrbus]

A high doze of sodium like from the water softer will cause a problem with 304 grade SS also but not with 316 grade.
I have seen in the past tanks made from 304 ss and stick welded not Tig welded have problems


good luck

[JLL]

I didn't mention that the grit was black.  I filter all the water that goes in the tank.  I use a large taste and oder filter.  My water at home comes from our well.  I usually don't put more than about 75 gals in because we park in RV parks mostly.
Thanks for ther repleys
JLL

[Len Silva]

Is there a possibility that you just had a carbon filter that failed and dumped the black material?

[JLL]

hey guys
What is ( PASSIVATION )  ?
jLL

[kyle4501]

http://en.wikipedia.org/wiki/Passivation

http://www.delstar.com/passivating.html

[Chaz]

Hmmmmm....

I didn't mention that the grit was black.

So I opend it up and found it pluged up with black grit about the consistency of suger.

Did I read that wrong? That's what I was going by to try to help figure out what it was. Was it something else?

Just curious,
   Chaz