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Some truths on bleach dosing


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For every 100 gallons of water adding 1 tablespoon of:

5.25% bleach will raise FC by about 2 ppm

6.0% bleach will raise FC by about 2.5 ppm

8.25% bleach will raise FC by about 3.3 ppm

10.0% bleach will raise FC by about 4 ppm

12.5% bleach will raise FC by about 5 ppm

I have just learned that there is also 7.5% bleach being sold so I would expect the 7.5% bleach will raise FC by about 3 ppm

(these numbers are not exact but are in the ballpark. They have been rounded to make measurements easier but should be close enough to get you where you want to be or very close to it)

10% and 12.5% bleach are normally sold as "liquid pool chlorine"

6% laundry bleach is usually called "ultra bleach"

If you are using laundry bleach you want the plain,unscented, one with NO thickeners, detergents, or scents. The ingredients might list water, sodium hypochlorite, sodium chloride (salt), sodium hydroxide, sodium carbonate, and (for laundry bleach) polyacrylic acid (used to prevent soil from redepositing back on clothes and is also the main ingredient in many polymeric pool and spa clarifiers so the small amount in the bleach will NOT have any negative impact on your water). These are either added to stabilize the bleach or are the result of the manufacturing process and are a normal part of the makeup of bleach or liquid chlorine.

The ONLY differences between the different strengths of sodium hypochlorite is how much is needed to reach a given FC level in a given volume of water and the shelf life of the bleach. The more concentrated strengths need less to achieve a given FC level in a given volume of water and have a shorter shelf life before they start to degrade and lose strength. There is no reason you can't use old bleach as long as you are testing the FC and adding enough to achieve the desired level.

 

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Quick question @waterbear

I have a household bleach here in Canada called Old Dutch.

According to the MDS it looks like this product may fall below the 3%  Bleach levels

 

Sodium Hypochlorite  WT% 1.0-3.0

Sodium Hydroxide       WT.%  <.05

 

From what I can tell this may between 1% to 3% Bleach

Would I be reading this correctly? Seems fairly weak 

At this level would you suggest perhaps 2tbs to get the 2ppm FC

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9 hours ago, Fingerstank said:

From what I can tell this may between 1% to 3% Bleach

Would I be reading this correctly? Seems fairly weak 

yes, It's basically a 'dollar store' bleach (Very dilute so it can be sold for a low price). This weak strength of  bleach is also sold in the US. It's not worth the money. Get some Clorox or a house brand like HDX from Home Depot or Great Value from Walmart. They might cost a bit more but are 5.25% to 6% (read the label or if it's not on the label look up the Safety Data Sheet online. You might also be able to find liquid pool Chlorine at Lowes, Walmart, or Home Depot during pool season.

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Thanks for the input.

Think I will just grab some pool chlorine. But with that being said yes it's much cheaper way to go but it's also in a higher volume container than I would probably go thru in a year. I have read that chlorine can weaken over time, not sure how that is possible but hey I am not a chemist :)

 

Still working on managing the Dichlor and Bleach method :)

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4 hours ago, Fingerstank said:

I have read that chlorine can weaken over time, not sure how that is possible

chlorine gas leaves the solution. The sodium hydroxide is there to slow the process down.

 

4 hours ago, Fingerstank said:

but it's also in a higher volume container than I would probably go thru in a year.

It's just chlorine bleach. If you get the 10% just use half the amount of regular bleach in your laundry or other cleaning needs. If you get the 12.5% use half the amount of ultra strength bleach. Just dilute them.  It's not rocket science. Bleach is bleach.

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