Breakpoint chlorination is the point where chlorine levels exceed the oxidant demand. Natural oxidant demand refers to the consumption of an oxidant due to reactions. Natural organic matter has a high oxidant demand. Theoretically, exceeding the “breakpoint” prevents increased levels of disinfectant byproducts (like chloramines, or better known as combined chlorine) and the water begins to build a residual of free available chlorine (FAC).
Very simply, it means if you don’t put enough shock in the pool to oxidize ALL of the contaminants (combined chlorine) you make the situation worse. It’s all or nothing.
1 lb. of our Burnout3 by BioGuard (Calcium Hypochlorite) per 10,000 gallons of water oxidizes .8PPM (parts per million) of combined chlorine. If your combined chlorine is 3.5PPM (total chlorine is 5PPM and free chlorine is 1.5PPM) how many pounds of BurnOut3 would you have to add to break the separation?
It would take 4.375 lbs. of BurnOut3 per 10,0000 gallons. This means for a 25K gallon pool, you’d need to add eleven pounds of shock. If you add less, NOTHING IS OXIDIZED and you now have more combined chlorine.
There are other oxidizers you can use that eliminate this problem. Potassium Monopersulfate is one. This product does not require that you get break-point. If you use one pound of this product, it oxidizes 1PPM of combined chlorine per 10K gallons (ie/ if you put in 2.5 lbs, you oxidize 2.5PPM). This is a tremendous advantage – plus it contains no calcium or stabilizer, so you don’t need to worry about that, and you can swim in fifteen minutes. The disadvantage is that it costs more than calcium hypochlorite.
That is why we normally recommend you use a combination of both products. First the potassium monopersulfate to bring contaminants to a manageable level, and then finish them off with calcium hypochlorite.
Bring a sample to your nearest Texsun Pools location to have it professionally tested. While you’re there, ask questions on how you can eliminate and control chloramine build up in your pool.