Pool Math question. How much Calcium Chloride to add to bring up CH?

[boringforumname]

If you google this question or if you look at the instructions for some calcium chloride packages you will get the standard answer that seems most common, which is about 1.25 lbs to raise 10 ppm in 10,000 gallons. Some other sources say 1 - 1.25 lbs to raise 10 in 10k. Pool Math http://www.troublefreepool.com/calc.html says exactly 15 oz to raise 10 in 10k. Why the difference? Does it depend on other factors or what kind of cal-chlor you buy?

 

[jblizzle]

You missed that PoolMath also says:

or add 20 oz by weight or by 23 oz volume of calcium chloride dihydrate.

which matches what your google-foo returned

Depends if you get calcium chloride OR calcium chloride dihydrate

 

[boringforumname]

Hmmm....I see that, but now I'm actually more confused. Most of what I've seen that quotes the standard 1.25lbs to raise 10ppm in 10k mentions calcium chloride, or hardness increaser, but do not specifically mention "dihydrate." For example, this guy HOW TO RAISE CALCIUM HARDNESS IN A SWIMMING POOL - YouTube (I sometimes watch his videos, seems pretty grounded) uses that same formula and states calcium chloride but does not mention "make sure you get dihydrate." This seems to be standard advice, not just with this guy but around the internet.

For example, this product is pretty typical for what you find Amazon.com : Pool Mate 1-2825 Calcium Increaser for Swimming Pools, 25-Pound : Patio, Lawn Garden. It recommends 1.25 for 10 in 10 and state on the box/package "calcium chloride" is the active ingredient, but does not mention dihydrate as far as I can see. Is it that just about every form of calcium chloride bought at a retail store or a pool supply store WILL be dihydrate even if it does not mention it on the package?

 

[RobbieH]

I posted this elsewhere but got no answer. I'll ask here to keep the CH question together.

I need 50-60 lbs of calcium chloride. Does this look like the right thing? This is about 1/4 the cost at Leslies.

Snow Joe 50 lb. Re-Sealable Bag Calcium Chloride Crystals Ice Melter-MELT50CC - The Home Depot

Or this, which is flakes...
Vaporizer 50 lb. Calcium Flake Ice Melt Bag-VP-CF50BG - The Home Depot

This one is a lot more, but they mention using it in pools
Amazon.com : North American Salt 50850 Extreme 7300 Calcium Chloride Ice Melter, 50-Pound : Snow And Ice Melting Products : Patio, Lawn Garden

Or any of them?

 

[WASP]

Beware Buying the snowmelt products. I tried that and it turned out to actually be sodium chloride. I'm not saying that all of the snowmelt products are mislabeled, but some are. Amazon refunded my money and removed the suspect product from sale. I just had 25lb bucket of pool calcium delivered by by Amazon for $37.

 

[borjis]

And you might consider a local pool store, just for the calcium.

That's what I do. Only thing I buy there, sometimes I pretend to be looking at pumps if a
customer is talking to the pool store employees (just for fun to see what advice they give)

The one I go to has 25lb bucket for $ 37, so same as Amazon without any shipment wait time.

 

[smackdab]

The "Pool" Calcium Hardness Increaser products are mostly if not all calcium chloride anhydrous. You would use calcium chloride in Pool Math. For the snow melt products like Peladow, you would use calcium chloride dihydrate in Pool Math. Some if not all the snow melt products are anhydrous, but they are a lower percentage (I recall 77% or so) of calcium chloride so the dihydrate section in Pool Math calculates correctly.

 

[RobbieH]

Leslie's is all I have, but I can go to the Commercial store tomorrow. They usually cut me a deal because I buy so much at once to maintain a 44k gallon pool. And, it's less than a mile away. Thanks for the help!