Dissolving Cal Hypo

[southernpool1]

Good morning!

I have recently been converted to the TFPC method of pool maintenance. However, I have 100 pounds of cal hypo that I just bought that I am trying to find a way to use. Over the weekend, a friend and long time pool owner told me that if you pour the shock into a five gallon bucket of water and let sit for 10 minutes, the chlorine unbinds from the calcium and other fillers. At that point you can pour just the water into the pool and throw out the remaining hard granules at the bottom of the bucket and the pool will only get the unbound free chlorine, which will not increase the calcium level.

Can someone tell me if this is accurate? I was thinking I could use the rest of my cal hypo this way and just use bleach in the future...thanks!

 

[JoyfulNoise]

Only PARTIALLY true.

It is true that the excess calcium hydroxide and calcium oxide will sometimes cause water to scale out calcium carbonate as a precipitate (it's called "lime softening") but there will still be some CH leftover in the water. However, there is also calcium carbonate in the cal-hypo and that will increase the CH of the water mix. Since the cal-hypo is mostly hypochlorite, the amount of lime softening that will occur will be fairly limited. So I doubt you'll see much, if any, improvement in the CH of your pool water.

Just another bit of misunderstood pool chemistry lore passed down by word of mouth....

 

[JVTrain]

Return it and get some bleach... or some pool toys.

Depending on your current CH level and the CH of your fill water, you could use it. CH doesn't matter much in vinyl pools but you don't want it to get above 350 ppm.

I doubt letting the undissolved portion remain in a bucket will reduce the CH addition much at all as it's probably just undissolved cal-hypo and there's already plenty of dissolved calcium in the bucket by that point as well.

 

[southernpool1]

I figured as much but still wanted to check. Thanks!