Proper procedure & timing check for adding 25-50lb of calcium

Apr 15, 2016
Central Florida
Need to help add 25-50 lbs of calcium chloride to a neglected plaster pool.
Questions so far:
1) Do I pour the calcium chloride or the pool water in the bucket first? (if doing multiple buckets, need to dry after each if calcium first?)
2) If using a 5 gallon bucket, is it okay to expect 10 pounds of calcium chloride and 4 gallons of pool water or do I need to do less at a time?
3) mix with something other than your own hand and arm - seconds or minutes? until no powder sitting on bottom? until even cloudiness?
4) Distribute/pour back in - in front of return, deep end, around perimeter?
5) Using PoolMath I have a good estimate how much I'll need, but since the calculated gallons of the pool are best guess, I'd like to sneak up on target CH. How long to wait between testings given excellent circulation?
6) How long does the pump need to run after last addition is complete? Normal addition time of 15-30, 2 hours, 24 hours?
7) I have a few spots where the plaster has de-laminated and flaked off, exposing sub-surface/gunite whatever. I've read about calcium sticking to bottom when not added correctly. Thoughts on intentionally adding it incorrectly to these flaked off areas in an attempt to make a cosmetic calcium patch? Would it just come off during normal brushings?
8) PH was 7.5 at last check before FC was sent over 10, advise dropping to 7.2 with MA before CH addition to potentially reduce clouding?

Thank you!


TFP Expert
LifeTime Supporter
Jun 7, 2011
Midland TX
Don't mix it in a bucket first. Exothermic reaction takes place which makes it quite hot. I hope others will weigh in, but all I can add for certain is don't do this with high pH in the pool, and avoid additions that will even temporarily increase pH such as a large Bleach addition soon after. Doing so may precipitate the Ca and cloud your water.

I would think 7.2 a great place for adding, but I have no idea about getting it to stick to the bare spots. Or if it would last should you have success with that. If it were me, would add in smaller doses at first to see what happened. This seems to be coming up a lot lately, and I just fail to remember how many people do this, but I always wonder why more members simply aren't using Cal Hypo in these soft water pools?

It's a moot point here, I guess, but It really makes me curious, because I have the opposite problem you do. I wish we could trade some water, and we would both be happy! :lol:
Apr 15, 2016
Central Florida
Thank you. At least in my case, I pay $1.04-$1.80 per gallon* for liquid 10-15% at my local Florida Leslies after all their discounts/rewards and the calcium was $20.72 for 50lbs through Sam's Club, so it was just a thrift decision not to calhypo over time.

Anyone know if slow pour in front of return or slow, light sprinkle over deep end is the way to go here? Brushing either way, of course :) If not, I'll just trial and error and share results. No harm done if I damage a plaster that's already doomed :) Might use BBQ thermometer to record one bucket of premix just for curious minds wondering what the temp gets to with commonly suggested max cal-to-water ratio.

*edit - this does not include the cost of replacement 2.5 gallon jugs that seem to be getting cheaper and cheaper over the years. I might look into a more durable container, perhaps carboy or whatever. This is all assuming I don't break down and get a stenner pump and drum.