CH increaser and Calcium Hypochlorite question

[botanica37]

I need to bump up my CH from 160 to 250 and while pondering the pool calculator it occured to me that I could use Calcium hypochlorite to keep the chlorine up to shock level and at the same time raise the CH - is that a correct assumption?

FC 10
PH 7.2
TA 70
CH 160
CYA 60

Thank you!

 

[JasonLion]

Yes, using cal-hypo when you need to raise the CH level can work very well. Just keep in mind that you need to keep track of both the amount of chlorine you are adding and the amount of calcium you are adding and not add too much of either one.

 

[PaulR]

For cal-hypo, the ratio is every 10ppm FC also adds 7ppm CH.

You wanted to add 90ppm CH, 90/7=~13, so this would require about 130ppm FC worth of cal-hypo. If your pool uses, say, 2ppm FC per day, then it would take about two months of cal-hypo use to bring up your CH.

Up to you whether that's okay.
--paulr

 

[anonapersona]

Cal-hypo would also increase the CYA levels, right?

 

[JasonLion]

No. Cal-hypo has no effect on CYA.

Dichlor and trichlor increase CYA.

 

[anonapersona]

No. Cal-hypo has no effect on CYA.

Dichlor and trichlor increase CYA.

Leslies Powder Power Shock is 70% calcuim hypochlorite.... but is the other 30% including a stablizer?

 

[duraleigh]

but is the other 30% including a stablizer?

Nope CYA and stabilizer are the same product......none in Cal hypo.

You may be thinking of tri-chlor pucks that do contain CYA.

 

[chem geek]

Cal-Hypo comes in different strengths, typically 48%, 65% or 73%. These strengths are also roughly the % Available Chlorine. The rest is a combination of salt and excess lye (calcium based), not CYA. Generally, Cal-Hypo adds less salt for the same Free Chlorine (FC) as bleach or chlorinating liquid, but of course Cal-Hypo raises the Calcium Hardness (CH).

 

[CaOCl2]

For cal-hypo, the ratio is every 10ppm FC also adds 7ppm CH.

This is true in a strictly chemical sense, however do keep in mind that if you're going to add, say two scoops of cal-hypo to get your 10 ppm FC, the actual increase in calcium hardness will probably be more than 7 ppm because of the inert ingredients in the formulation. In my experience, the cheap 47% stuff adds quite a bit more than 7 ppm CH per 10 ppm FC.

 

[chem geek]

For cal-hypo, the ratio is every 10ppm FC also adds 7ppm CH.

This is true in a strictly chemical sense, however do keep in mind that if you're going to add, say two scoops of cal-hypo to get your 10 ppm FC, the actual increase in calcium hardness will probably be more than 7 ppm because of the inert ingredients in the formulation. In my experience, the cheap 47% stuff adds quite a bit more than 7 ppm CH per 10 ppm FC.

This is true. Though most of the inert ingredients are regular salt (sodium chloride), there is also calcium chloride, calcium hydroxide, calcium carbonate and calcium chlorate all of which would increase Calcium Hardness (CH). Do you have such a < 50% Cal-Hypo product and does it list the amount of these inert ingredients individually? I found MSDS for more concentrated products, but not for ones with < 50% Calcium Hypochlorite.

Richard

 

[robrinker]

I found this link that contains an MSDS for HTH Chlorinating Granules (which is 47.6%). I just purchased a 55lb bucket of this stuff, because I also need to raise my CH.

http://www.kellysolutions.com/AK/showpr ... =1258-1237

I'll be interested to read your findings, Chemgeek.

 

[chem geek]

Interestingly, this Cal-Hypo 47.6% product contains mostly magnesium sulfate heptahydrate as its main "filler" ingredient. There is also standard salt (sodium chloride) and some amount of calcium salts but this product probably won't add more calcium per FC than other stronger Cal-Hypo products. It will, however, increase magnesium, which is not a big deal, and sulfate, which might be an issue accelerating corrosion of stainless steel in salt pools if it got very high.