Fresh water galvanized tanks, rust

[lumpy]

Sent: 8/5/2008

I have done multiple searches and most say the old galvanized tanks were glass lined?
Well mine are full of rust sediment and after draining them , pressurizing them , draining them ...... well you get the picture.
i still have rust sediment in them .

My system works flawlessly and really do not want to change them out till i really have to . I had a water heater that failed and was rusted out badly and leaked. It has since been replaced, I wonder if when draining back the system it has sucked this water heater rust into the main tanks?

I do not want to continue using the galv. system if I am risking a failure due to the tanks themselves rusting, but if they are glass lined like I have read I doubt they are rusting.

Any thoughts? I like the pressure system over the demand system due to the pump not running all the time as I mentioned it is working great. Not getting rust at the taps just in the bottom of the tanks

thanks, Er (TANKS)

Mike

[denisondc]

Sent: 8/5/2008

I don't know what kind of glass they lined the tanks with, but the home water heaters I have replaced over the years said they they were glass lined too. They all had plenty of rust in the bottom when I would drain them as part of replacement.. So I suspect the 'glass lining' just slows down the eventual rusting.

[Lefty]

Sent: 8/5/2008

The actual tank may, or may not be glass lined. I've never cut one open to see. I know home hot water heaters are, but not for the reason you think.
Glass, when coated with a reflective spray, is an excellent insulator. Especially when it also is wrapped with additional insulation like fiberglass. For this reason, hot water tanks are glass lined to increase thermal efficiency.
A cold water storage tank has no need for insulation, other than to keep the contents from freezing that is... And as anyone who has ever owned a glass lined Thermos bottle can tell you, vibration and glass don't mix. So having a fragile glass lining inside a motorhome tank containing about 200+lbs of water, bumping and vibrating down the road wouldn't be a very smart idea.
But, as I said, I don't know if they are lined or not. Even if they were, you would still have rust forming from all of the metal fittings that are attached to the tank.

[ibdilbert01]

Sent: 8/6/2008

I cut mine in half before I took it to the scrap yard, It rusted from the inside out, and if it once was lined, there was no signs of it. Mine was the original galvanized tank in my 72. I replaced it with a 30 gal plastic that I purchased on eBay, and a Sureflow on demand pump also purchased on eBay.

On my 72 brave, there is not as much room under the back gaucho as one would think and the 30 gal fits with some room to spare. I wish I would of tried to fit a larger tank back there.

[tiinytina]

Sent: 8/10/2008


Galvanizing, coating with Zinc, does slow down the formation of rust but like all of nature a system strives for equilibrium. Zinc is a positive ion and so it gets pulled away by basic or negatively charged ions from water that is "soft". Many home water heaters usually have sacrificial cathode/anode that gives up or takes free ions out so that the zinc or other metal parts of the system do not get degraded. We bleach and drain our hot water tank about 2x a year in the house and the sediment is not pretty.... As long as you aren't not using the water in the system for "drinking" I wouldn't think it would be an issue. I would be careful with a pressure tank though because if it springs a rust through leak it won't be pretty, and a nice pin hole leak, as we found in a hot water heater connection in Gone, can cause a lot of damage if not found and corrected.... Our leak was under the bed in a corner and by the time we found it rotted the floor out.... then some...

Tina