Can I use potassium metabisulphite to clean my water tank?

[luciarose]

We have a 250 gallon aluminum water tank. After the winter, the water tastes and smells somewhat so I want to flush the tank. I don't want to use bleach in the tank so I'm looking for an alternate, safe method of disinfecting the tank and lines. It seems that potassium metabisulphite would be a safe bet considering it is used to pickle watermakers and is used in the beer and wine industry.

So, has anyone had experience with using this as a tank sanitizer? What concentration would I use? I have an 8 oz bag of the stuff. I was thinking of premixing with water and pouring into the tank, letting it run through the lines for a few minutes and then letting it sit for 30 minutes before flushing the entire system with clean fresh water.

[jhstacy]

I also have an IP-35 that I just bought a few months back and I would love to know if there is a safer chemical that is less caustic on the Aluminum tanks so have the same question as well

[model 10]

If it's not a money issue with your investment in the watermaked cleaner, try citric acid. It might be considered the better choice and it's cheap at beer and wine making supply stores. And, you can use it to clean your stainless on deck!

[SV THIRD DAY]

Sodium Metabisulfite or Potassium Metabisulfite are used commercially in the food industry to clean vats, tanks, etc, so you will be ok to use it in your Al water tanks and plumbing...but it's also going to take more than a few tablespoons! The sterilizing ratio is two tablespoons per Gallon of water so for a 100Gallon tank that's 200 tablespoons.

Fill the tanks and all the lines with the soup and then let it sit overnight.
Then flush out the tanks to remove the bad taste it will give if you don't get it all out. It won't hurt you (FDA Food Grade) but it taste BAD.

[hellosailor]

It should be OK as a tank sanitizer, the brewers seem to think it is the best choice for not altering flavor. Be aware that the US EPA decided that since it kills microcritters, it is a pesticide or fungicide or some other -icide and want a finger in the pie. No idea if that will complicate purchasing "enough" of it, these days.


Basically, I think it is more expensive than bleach, so bleach is still preferred when the priority is "just" nuking something. And the brewers always use the good stuff on glassware that has already been thoroughly cleaned--which the insides of your water system might not be.

[HopCar]

I sell a product for cleaning water tanks called Puriclean. It seems to have worked well when I used it. It is safe in aluminum tanks. The active ingredient is Sodium Dichloroisocyanurate (NaDCC). It's made in the UK.

Info: http://www.cleantabs.co.uk/puriclean.htm

Order: Puriclean - MFG#UPCSTD - 14 oz. Tub

Practical Sailor Mag is running a series of articles on maintaining potable water systems on boats. The one in the current issue is about pre-filtering the water before it goes into the tank. Other articles will address cleaning the tank, maintaining clean water in the tank and filtering as it comes out of the tank.

The articles were written by Thinwater, one of our fellow CF'ers.

[jhstacy]

This chemical NaDCC is a Chlorine donor, so chemically, the CL-AL bond is still going to occur and this is not much different than pouring the Chlorine bleach in the tank. We are trying to avoid the degradation of the AL tank by use of Chlorine

[thinwater]

Originally Posted by jhstacy

This chemical NaDCC is a Chlorine donor, so chemically, the CL-AL bond is still going to occur and this is not much different than pouring the Chlorine bleach in the tank. We are trying to avoid the degradation of the AL tank by use of Chlorine

Obviously we know that. Please, do the corrosion testing for yourself. It is at least an order of magnitude less on the alloy I looked at.

Why is it slower? I believe the isocyanuric acid that is part of the equilibrium is a reasonably effective inhibitor in this environment, and others have found the same thing. It's ability to protect stainless is very well documented. This is a common behavior of complex organic acids--all of our engine coolant corrosion inhibitor technology is based upon organic acids. Other theories suggest that cyanuric simply lowers the activity of the free chlorine; I didn't study that.

Is there a disinfection agent that is completely non-corrosive to aluminum, effective, safe, and aesthetically acceptable? Please share. I don't have a dog in the fight and I would LOVE to know.

[Rustic Charm]

Chlorine?

Pool chlorine.

[Rustic Charm]

And flush it out with lots of hydrogen monoxide.

Careful with that staff, you don't want to breath it as it can be fatal. And if any gets on your metal wipe it dry or it will increase rusting

[colemj]

hydrogen monoxide? Did you mean dihydrogen monoxide?

Mark

[zboss]

For brewing, we really don't use P/S metabisulfate for sanitizing equipment anymore (at least not for more advanced brewers) as there are much better options.

For the water itself you don't really need to use it because ensuring a robust fermentation results in the alcohol killing or arresting the growth of just about anything. Usually, its used for removing chlorine from city water before brewing or for stabilizing wine and halting yeast activity.

FYI - I used it in my aluminum mash tanks just fine... the contact time is not significant and it evaporates out quickly. It doesn't do a good job getting past the biomass slime on tubing however. For that you need to use a cleaning agent like oxyclean and TSP followed by an acid bath.

[Rustic Charm]

Originally Posted by colemj

hydrogen monoxide? Did you mean dihydrogen monoxide?

Mark

I did yes.

[Rapanui]

I have a question regarding removing hard water scale from water tanks. We have a lot of scale in our tanks and frequently it fills up the water pump pre-filter with bits of scale. Would Puriclean or any other tank cleaner remove this scale from the tanks? It would need to be something you can afford to use diluted in say 40 gals of water to clean the whole tank x 2.