Is anyone able to explain to me, or direct me to a post or resource, that explains to me, the specific chemical interactions and by products of each of these sanitizing sources?
Trichlor vs dichlor vs sodium hypo vs cal hypo
- Thread starter JimMarshall
- Start date
Pool School - How to Chlorinate Your Pool
If you want specifics, go to PoolMath Enter your numbers and ask it to calculate how much to add to raise FC some amount, say 3 FC. Use the dropdown to get quantities of different forms. Then go to the bottom of poolmath where there is Effects of Adding Chemicals and plug that amount in and it will tell you what each will add.
If you want specifics, go to PoolMath Enter your numbers and ask it to calculate how much to add to raise FC some amount, say 3 FC. Use the dropdown to get quantities of different forms. Then go to the bottom of poolmath where there is Effects of Adding Chemicals and plug that amount in and it will tell you what each will add.
Richard, I was wanting to dive deeper into the actual chemicals that each of these separate into upon additon into a pool, essentially the proof that chlorine is chlorine is chlorine is chlorine
Funny, that seems far more like the logical position, that Cl2 is Cl2. It would make more sense to search out those who say otherwise and ask them for proof that Cl2 from one source is not the same as Cl2 from another source.
I think the issue is what else beside chlorine is in each of these.
Trichlor and dichlor add cya, so at some point if you use these constantly, your cya levels will get too high, and partial pool drain pool is only recourse.
Cal hypo adds calcium, so if you use it your calcium levels will get too high after time, and again partial drain is solution
Lithium hypo issue is cost
Trichlor and dichlor add cya, so at some point if you use these constantly, your cya levels will get too high, and partial pool drain pool is only recourse.
Cal hypo adds calcium, so if you use it your calcium levels will get too high after time, and again partial drain is solution
Lithium hypo issue is cost
Are you asking out of curiosity or are you wanting to prove a point to another person? Most of us are not chemistry experts, but you can google the msds for any product and it will point you to a document that lists the chemical make-up of that product. I'm not exactly sure what kind of information you are looking for. The article Richard linked in his post talks about what each type of chlorine adds to the pool other than chlorine and how that may effect pool maintenance.
Oly
Gold Supporter
Yes it does thanks ping. Post #4 by chem geek in that old thread spells it out nicely. Check your moles. 
From Richard's post:
"You need to use the proper molecular weights for measurements. For chlorine, it is measured in ppm Cl2 that has a molecular weight of 70.906 g/mole while for CYA it's in ppm CYA itself which has a molecular weight of 129.075 g/mole. You do not use the molecular weights of Trichlor or Dichlor themselves since the rule is comparing ppm FC vs. ppm CYA.
Trichlor has 3 chlorine attached to a CYA core (s-triazine ring) and they all can produce hypochlorous acid in water. So, 1 mole of trichlor produces 3 moles of chlorine and 1 mole of CYA. So the ratio of ppm CYA to ppm FC is 129.075/(3*70.906) = 0.60679. Dichlor has 2 chlorine attached to a CYA core so 1 mole of dichlor produces 2 moles of chlorine and 1 mole of CYA. So the ratio of ppm CYA to ppm FC is 129.075/(2*70.906) = 0.91018.
What's really confusing is when one starts talking about "% Available Chlorine" which is a weight %, but 100% is defined relative to chlorine gas and only one of the two chlorine in chlorine gas produces hypochlorous acid while the other produces chloride (from hydrochloric acid when chlorine gas combines with water). So every chlorine atom that produces hypochlorous acid is counted twice in terms of weight %. Trichlor has a molecular weight of 232.4103 g/mole so the % Available Chlorine is 3*70.906/232.4103 = 91.527% even though the weight % of atomic chlorine in Trichlor is half that percentage. Trichlor is around 99% pure product which is why the % Available Chlorine is usually quoted as 99%*91.527% = 90.6% or thereabouts.
Similarly, Dichlor dihydrate has a molecular weight of 255.97766 g/mole so the % Available Chlorine is 2*70.906/255.97766 = 55.400%. For Cal-Hypo with a molecular weight of 142.98366 g/mole and producing 2 chlorine for every mole of calcium hypochlorite (remember that it is Ca(OCl)2), the % Available Chlorine is 2*70.906/142.98366 = 99.181% so is essentially the same as it's purity so that 65% Cal-Hypo is around 65% Available Chlorine (64.468%, actually), etc. Sodium Hypochlorite has a molecular weight of 74.4422 g/mole and each mole produces one mole of chlorine so the % Available Chlorine is 70.906/74.4422 = 95.250% so is close to the weight % (purity) of product. This is why 6% bleach (which means 6% by weight of sodium hypochlorite) is 6%*95.25% = 5.715% Available Chlorine.
Yet another confusing number that is used is Trade % which is the Volume % of Available Chlorine (as opposed to Weight %). This factors in the density of the product where the Trade % is the (weight) % Available Chlorine times the density (specific gravity). Since 6% bleach has a density of around 1.08, it's Trade % is 5.715%*1.08 = 6.172%. When one wants to easily calculate the FC rise of adding 1 gallon of chlorine to 10,000 gallons of water, it's the Trade % that is most easily used since the rise is 6.172 ppm FC.
Richard"
PS - I miss this guy.
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