Welded Steel Storage tank....... unpressurized

[boilERIK]

I am busy planning a 1000 gallon unpressurized storage tank. the tank will have heat plate exchangers for the boiler and on the distribution side. The local fabrication shop is able to build me a tank with the necesary fitting and dimensions for my space. They have been suggesting an 1/4" aluminum plate tank. I have done some reading on this and Alumuminum seems like not the best choice. My question is will a fabricated steel tank have major corrosion issues? or will I be able to manage the ph and keep it in acceptable levels to minimize corrosion of the steel tank? Is there a coating I could use to isolate either the steel or the aluminum tanks? Thanks

 

[cityboy172]

I'd run steel and moniter your water quality. At least thats what I plan on doing. Plan on building one out of 5 4x8 sheets, and that should get me just under 1000 gallons. No different then any of the steel pipe in the system.

 

[Chris Hoskin]

Sorry, an unpressurized steel tank is a bad idea. pH is not the problem, oxygen is. As an unpressurized tank, the water in the tank will be continually exposed to new oxygen and the tank will rust.

 

[Fred61]

Sorry, an unpressurized steel tank is a bad idea. pH is not the problem, oxygen is. As an unpressurized tank, the water in the tank will be continually exposed to new oxygen and the tank will rust.

And supports corrosion from electrolysis. That's why you'll see a large amount of corrosion concentrated in one small area.

 

[jeffesonm]

These guys make unpressurized tanks: http://www.americansolartechnics.com/

Or if you really wanted to DIY, you could build a frame and then drop an EPDM liner in there.

 

[bmblank]

My brothers unpressurized steel tank (1600 gal) is just fine. As is mine. They are buried though, so I suppose oxygen is low. In general, though, with the constant heating and cooling, oxygen content will be low, and as long as you're not churning up the water, it'll stay relatively low.

 

[peakbagger]

Folks used to use 275 gallon oil tanks for unpressurized storage, they would eventually leak and were generally unrepairable plus made a mess as the leak was rusty. I think Tom in Maine has had lots of experience with those installations.

 

[maple1]

These guys make unpressurized tanks: http://www.americansolartechnics.com/

Or if you really wanted to DIY, you could build a frame and then drop an EPDM liner in there.

That's likely what I would do for unpressurized. Wood frame & box, & line it. Really good for putting a tank in a restricted space too.

 

[peakbagger]

I have personal experience with EPDM (far more than ever care to ). Continuous immersion at elevated temps deteriorates it. Welded PVC from American Solartechnics is the way to go

 

[Dextron]

We had a 1600 gallon steel tank for water where I work until city utilities became available. It was in use for 25 years. A water truck topped it off every other day so it was quite aerated. It sat mostly empty for a few years until we finally removed it. We had to cut it in half to get it out of the building. It had been painted back when it was built and it still looked like new inside. We were all amazed but I think this shows steel can work well if treated correctly. It was always used for cold water so I suppose hot water may have had different results.

 

[mmudd]

I have a 450 gallon well built homemade wood insulated tank you could have . It will need a liner and a top, but it is along way from MA. I converted to pressurized storage last year. Pics available if interested