5 days of "burn out"???

[chem geek]

Well, Burn-Out Extreme (Cal-Hypo) isn't a very effective way of adding a LOT of calcium since even after five 1-pound bags you will only raise your CH by 17 ppm. Adding Calcium Chloride will get your CH up as well and is probably a lot less expensive. I remember buying a 50-pound container after I did a half drain and refill equivalent using winter rains, so needed to get my CH back up. You should probably test your CH level to see what it is. If you pool is new plaster or re-plastered, then calcium hydroxide will get into the water from the plaster as the plaster cures. That will add calcium to your pool and will raise the pH so expect to be adding lots of acid over the next few months to maintain the pH. At any rate, you probably want to do what your pool builder says regarding calcium levels assuming you are under some sort of warranty for this job.

So, I agree that using Cal-Hypo makes sense as your chlorine source while you are needing to raise the CH, but if you need to raise it quickly then adding calcium chloride is more cost-effective. In other words, I would do both -- use calcium chloride for the bulk of the increase you need (remembering that more calcium will be coming from your plaster during curing) and use Cal-Hypo for chlorine until the CH is where you want it.

Richard