black spots inside aluminum tank??

[Rooster1]

I looked inside one of my aluminum tanks today and it had many black spots. We tumbled them with aggregate for a couple of hours and it cleaned up some but there is still spots. Any suggestions??

 

[OE2X]

Mold?

 

[jfoutz]

Sounds like mold to me too. Unfortunately, I think most everything that kills mold is a liquid. (And you probably don’t want to mess with the gases that will work like chlorine.)

If it is mold, a weak bleach solution will do the job. One cup bleach per gallon of water, and let it sit for at least 10-15 minutes. Rinse and dry very thoroughly. If it was mold, the spots should disappear. Also, if it turns out to be mold, throw that aggregate that you used out – it can spread mold to other tanks. Also, question why you had mold growth in your tanks; mold can’t grow without moisture.

 

[OE2X]

All you need to get is a bad fill where you get moisture. It is likely that the moisture isn't pure and may have contained mold spores. I just recently had to have two - one year old steel tanks tumbled and O2 cleaned because they had rust in them. They had seen a lot of fills and very likely one of the compressors moisture traps was ineffective.

 

[Lil' Irish Temper]

Whatever it is, it can't be good :11:

 

[sailingking]

It might not be mold, there are many tanks that come straight from the factory with black stains on the inside. This is due to the manufacturing, nothing is wrong with them but they aren`t shinny like others. The best thing to do is to get a visual from somebody who knows what to look for.

 

[Rooster1]

It took 6 hours of tumbling with aggregate to get the stains out! The real strange part is that this tank was on a manifold with another tank and the other tank was in perfect clean condition and a year ago when they were o2 cleaned before being put together they were both clean.

 

[jbd]

It took 6 hours of tumbling with aggregate to get the stains out! The real strange part is that this tank was on a manifold with another tank and the other tank was in perfect clean condition and a year ago when they were o2 cleaned before being put together they were both clean.

Is it possible that the stained tank was not thoroughly rinsed and the cleaning agent reacted with the tank to cause the stain?

Was the stained tank the one connected to the fill station, and maybe something was introduced in to it from the fill station that didn't go directly into the other tank?

 

[Rooster1]

Is it possible that the stained tank was not thoroughly rinsed and the cleaning agent reacted with the tank to cause the stain?

Was the stained tank the one connected to the fill station, and maybe something was introduced in to it from the fill station that didn't go directly into the other tank?

they were both rinsed well. as far as the fills go I am not sure.

 

[jbd]

they were both rinsed well. as far as the fills go I am not sure.

Is this the first time you looked in these tanks or have you looked inside the tanks previously. If you have seen the inside of the tanks prior to this; are the stains something new this time?