adding calcium - 1/3 of the appropriate doze per addition?

nikon5400

Well-known member
Jul 20, 2013
217
Northeast
My hth bottles say "if large amount of calcium increaser hardness is required (an increase of more than 50ppm) add 1/3 of the appropriate doze per addition. Wait 4-6 hours between additions"

My clorox and aqua chem says "Divide total dosage into thirds. Add 1/3 at a time, waiting 6 hours between additions.

Why 1/3 at a time? Does it have anything to do with filter pressure or stains on the pump lid?

Why hth mentions 50ppm, while the other two don't?
If I need 50ppm and use hth, I can do it all in one shot but if I need to add 75 I should do 1/3 at a time??

Thanks
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
31,166
Laughlin, NV
It is best to add calcium chloride in small batches so you can be sure you get it fully dissolved when you broadcast it in the deep end. Brush well.
 

nikon5400

Well-known member
Jul 20, 2013
217
Northeast
It is best to add calcium chloride in small batches so you can be sure you get it fully dissolved when you broadcast it in the deep end. Brush well.
what is a small batch?

I needed about 50ppm and went with hth. 3 bottles, 6 additions (diluted with water before adding to the pool) but only 5-10 minutes apart. Only then I looked at instructions on other bottles (other brands), which don't mention 50ppm.
I brushed after each addition, didn't see anything on the pool floor
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
31,166
Laughlin, NV
2 or 3 lbs at a time. More if the water is warm and it dissolves fast.

Be careful dissolving in a bucket. Exothermic reaction.