I need to add about 16lbs of Calcium Chloride to my 17K plaster pool, its currently measuring at approx 250 and will bring it to 350 and remeasure. Being in Florida getting deicer isn't the easiest thing to do, but the internet is my friend and Homedepot is close by: 25 lb. Professional Strength Calcium Chloride Pellets Ice Melter - Re-Sealable Bag Model # 206402769 $16.99, with FREE SHIPPING to store.
Looks like a winner at 94% Calcium Chloride.
5lbs of CH increaser is $10, so it seems like a no brainer.
Hope the info helps others.