Quote Originally Posted by smallpooldad
Is it possible for you to supply the equations, when you have time?
I'll try to keep this as brief as possible and hope you or your neighbor know enough about chemistry to believe the math.


Tri-Chlor + 3H2O --> CYA + 3HOCl
See the chemical structure for Tri-Chlor and CYA and notice that Tri-Chlor has 3 chlorine atoms that get replaced with hydrogen when dissolved in water. These chlorine atoms are Cl+, not chloride (Cl-) so they combine with OH- from water to form HOCl while the H+ from water becomes part of CYA (which is a weak acid).

(8 oz./tablet) * (28.349523 g/oz) / (232.4103 g/mole Tri-Chlor) = 0.9758 moles Tri-Chlor/tablet

(0.9758 moles/tablet) * (129.075 g/mole CYA) * (1000 mg/g) / ( (10,000 gallons) * (3.7854 liters/gallon) ) = 3.33 mg/l CYA = 3.33 ppm CYA

(0.9758 moles/tablet) * (3 chlorine/molecule) * (52.4603 g/mole HOCl) * (1000 mg/g) / ( (10,000 gallons) * (3.7854 liters/gallon) ) = 4.06 mg/l HOCl = 4.06 ppm chlorine

There is no calcium in Tri-Chlor so 0 ppm calcium.


Ca(OCl)2 + 2H2O --> Ca(2+) + 2HOCl + 2OH-

(7 g/tablet) / (142.98366 g/mole Ca(OCl)2) = 0.04896 moles Ca(OCl)2/tablet

There is no CYA in Ca(OCl)2 so 0 ppm CYA.

(0.04896 moles/tablet) * (2 chlorine/molecule) * (73%/100 purity) * (52.4603 g/mole HOCl) * (1000 mg/g) / ( (10,000 gallons) * (3.7854 liters/gallon) ) = 0.10 mg/l HOCl = 0.10 ppm chlorine

(0.04896 moles/tablet) * (73%/100 purity) * (100.0892 g/mole CaCO3) * (1000 mg/g) / ( (10,000 gallons) * (3.7854 liters/gallon) ) = 0.09 mg/l CaCO3 equivalent = 0.09 ppm "calcium hardness"


Richard