Calcium Hardness Increase Issue

[Toxophilite]

I've long suspected my pool volume was a good bit higher than what I was told and tried to calculate at fill off 2 well hoses. I think we went more with a guess than anything.

According to Pool Math and the bags of hardness increaser, I should be seeing more than 2x the amount of increase in CH for an add. Basically, I've slowly raised my CH over the months, waiting to see if my fill was going to be an add, so it's just been the 4lb bags, a total of 4 adds in 6 months.

Each time, I get 10pmm increase, which holds steady till next add. The bag and Pool Math suggest 5lbs would provide 50ppm/10K pool volume, and even going to 20K on volume, that's still over 2x what I'm seeing. Any ideas on what I'm overlooking or calculating wrong?

 

[mknauss]

What exact calcium product are you adding?

 

[Toxophilite]

This one from Home Depot, which is supposed to only be calcium chloride: Pool Time 4 lbs. Calcium Hardness Increaser Balancer 23504PTM

 

[mknauss]

SDS says calcium chloride.

Not sure what is going on.

 

[Toxophilite]

Thanks! I noticed the math on their larger buckets are a little different in ratio than what these little 4lb bags say, which are more in line with Pool Math for calcium chloride. Not too concerning, as it is working, other than trying to get to a closer pool volume via my Pool Math. I know it's off, just not that off.

I did a hard bump one weekend and 2 4lb bags got me from 180 CH to 200. Same thing.