Headmistress - Water Tank Cleaning Question

[CertaCito]

Dear Headmistress,
I wonder if you could clear up some confusion I have regarding correct quantity of bleach to water for boat water tank cleaning purposes? I have variously found the following formulas when searching the net for water tank cleaning information:

30 gallon capacity water tank for illustration:

Formula Result
2 oz bleach per 1 gallon of water = 12 fl oz for a 30 gallon capacity tank
8 oz bleach per 10 gallons of water = 24 fl oz for a 30 gallon capacity tank
1 qt bleach per 50 gallons of water = 19 fl oz for a 30 gallon capacity tank
4 oz bleach per 5 gallons of water same as 8 fl oz per 10 gallon answer
16 oz bleach per 25 gallons of water = 19 fl oz for a 30 gallon capacity tank
2 oz bleach per 15 gallons of water = 4 fl oz for a 30 gallon capacity tank
2 oz bleach per 5 gallons of water = 12 fl oz for a 30 gallon capacity tank

I think all of the above formulas came from postings that quoted you or the code that covers plumbing and electrical. I did see one posting from you that indicated someone had modified your formula and that his was not correct. Due to the frequent clogging of my in-line to the water pump mesh screen Shurflo filter by what looks like some kind of slime I need to shock clean four water tanks and I don't want to use too much or too little bleach for the job.

Many Thanks

CertaCito

 

[Peggie Hall HeadMistress]

No wonder you're confused!

"2 oz bleach per 1 gallon of water = 12 fl oz for a 30 gallon capacity tank." My math skills aren't what they used to be...but seems to me that should work out to 15 oz in 30 gal/water.

Also seems to me that somebody should have noticed that there's no way that 2 oz bleach in one gal of water and 2 oz bleach in 5 gallons of water can both equal 12 oz bleach in 30 gallons of water.

Buried in all that gobbledegook IS the right ratio: 2 oz of 5-7% bleach per gal. water...which works out to a quart/liter in 50 gallons. It doesn't have to be exact to the mil, it'll do the job if you get it within an ounce or two.

Do you have the rest of the directions? If not, I'll post 'em again.

 

[Ted]

Water Tank Cleaning Question

Check your math again. LOL I believe that 2 oz of bleach per gallon of water should equal 60 oz of bleach per 30 gallons of water.

 

[Peggie Hall HeadMistress]

Damn typos...and now I'm confused! One more try!

No wonder there are 42 different wrong amounts all over the net!
Thanks for catching that one so quickly, Ted!

1 quart of bleach to 50 gals water gets the job done...that works out (I think...wanna check my math again, Ted?) to 3.3 oz/5 gal. IMO, 3.3 is splitting hairs...round up to 4 oz/5 gal if you have a water tank smaller than 50 gallons...convert to 1 quart in 50 gal if your tank capacity is a multiple of 50.

 

[CertaCito]

Water Cleaning Directions - Thanks and Yes Please

Wow, what a quick reply. Terrific. Yes, I'd very much appreciate having the rest of the directions.

Thanks very much

Certa Cito

"2 oz bleach per 1 gallon of water = 12 fl oz for a 30 gallon capacity tank." My math skills aren't what they used to be...but seems to me that should work out to 15 oz in 30 gal/water.

Also seems to me that somebody should have noticed that there's no way that 2 oz bleach in one gal of water and 2 oz bleach in 5 gallons of water can both equal 12 oz bleach in 30 gallons of water.

Buried in all that gobbledegook IS the right ratio: 2 oz of 5-7% bleach per gal. water...which works out to a quart/liter in 50 gallons. It doesn't have to be exact to the mil, it'll do the job if you get it within an ounce or two.

Do you have the rest of the directions? If not, I'll post 'em again.

 

[drdanj]

Bleach alternatives

West Marine has several non-bleach products for cleaning drinking water tanks. I've seen products like Purogene or AquaoSol for example. Any thoughts on using these instead of bleach?

Dan
Tao
Catalina 36

 

[Peggie Hall HeadMistress]

"Additives" may mask the taste/smell of funky water, but none are a substitute for maintaining the system. Besides, adding something to every fill becomes a lot more expensive and is more of a hassle than recommissioning the system once or twice a year.

Purogene does put instructions for recommissioning (sanitizing a system) on their website, but it's also a chlorine product, so it doesn't have any real advantage over bleach. I couldn't find any info on Aquaosol...or Aquosol...or Aquasol, so I can't comment on it. I did find a product called Aquabon on the WM site...at $14 plus shipping for an 8 oz. bottle of stuff that requires one ounce for each 20 gal--ye gods, that's at least for every $15/tankful of water!

Stick with bleach...it's tried and true...and CHEAP!