# Two Letters Re: Seeking Advice on Swimming Pool Chlorine for Treating Drinking Water

Jim:
I had to write you and correct something that could lead to health damage or even death from the use of chlorine [for water treatment]. People have to know that this use [of chlorine] is for treating water [shortly before use], not long term storage. If you have a water supply that you intend to drink/use within a month, then chlorine (as long as it’s pure – as you so instructed) is fine. But it is not for long term storage!
When water is treated with chlorine, and then sealed in a container, the chlorine degrades over a short time period. Depending on variables (mixture, amount of water, heat, et cetera) this could be as soon as 2-3 months. As it breaks down, it releases chlorine gas, which does nothing to protect your water, but it can cause health problems (obviously) and it will also degrade and weaken your container.
There are products out there that can be used for long term water storage. (Stabilized Oxygen is but one of them.) These products can keep water stored safely for up to five years, with no bacteria or algae growth. – Kurt

James Wesley:
I can’t remember where I got this, but thought it might help with the question of “how much” in chlorinating water…..

Chlorination
Two common forms of chlorine compounds can be used, those disinfectants that contain Sodium Hypochlorate (household bleach) or Calcium Hypochlorate (swimming pool chlorine powder). It is very important that Chlorine is added to water at the correct dosage. Firstly, calculate the amount of water in the tank by using the following formula:
3.14 x radius2 x height of water in the tank (meters) x 1000 (The radius is half of the width of the tank)
Once you have calculated the volume of the water in the tank then place 40 milliliters of Sodium hypochlorite or 7 grams of Calcium Hypochlorite for each 1000 liters of water in the tank.
For example, if the tank’s dimensions are 5 meters wide, 3 meters high and there is 2.5 ml of water in the tank, the calculations would be as follows:
Volume of Water in the tank is:
3.14 x (5 x?)? x 2.5 x 1000 (liters)
Volume = 49,062.5 (liters)
40 x ( 49000/1000) = 1960 mils of Sodium Hypochlorite
Or 7x ( 49000/1000) = 343 grams of Calcium Hypochlorite

Regards, Terry M.