Using Calcium Hypochlorite and trouble keeping the PH down

[richc233]

After my "Freshman Year" in TFP Pool School, and a clear pool all summer after your help, I got the pool clear and clean quickly and easily this spring! However, I did get tired of bottles of bleach, needed some CH in the pool, and the price of Cal-Hypo was good (50 lb buckes from PoolSupplyWorld.com for about $110 free ship), so I have been using that for the last month or so. The only problem I have had is that the PH goes up with it and I have to keep adding dry acid to bring it down. I would say it will go from 7.8 back up to 8.2 in about a 1 1/2 weeks - adding about 1 lb of Cal-Hypo a day - we usually like to keep the PH at 7.6. I know that last year using bleach brought the PH down, so I am thinking to get some bleach and alternate between the 2.

My Levels:
FC = 5
CC= 0
pH = 7.8
TA = 90
CH = 250
CYA = 40+

Any suggestions would be great!

Thanks,
Rich

 

[jgofnj]

I was in the same situation where I was getting tired of adding bleach everyday or so. Finally decided to get the liquidator and so far happy with it, only fill up the liquidator with bleach once a week. Much cheaper than getting a SWG or a Stenner pump.

 

[cvgnus]

Hello Rich, based on TFP principles you should not use Cal-Hypo regularly as it adds calcium, raises PH and alkalinity. Liquid chlorine changes the chemistry of your pool the least (adds some salt) when it comes to disinfectants. It will raise PH slightly when added, but will lower as it is used or burned off. Using liquid chlorine likely didn't lower your PH, it was probably something else that did that last year. If you continue to use Cal-Hypo regularly you will likely remain on this roller coaster and eventually take your CH out of spec with it. It is a PITA hauling chlorine bottles and adding it everyday. But your prior year experience should indicate that sticking to TFP principles work. As jgofnj suggested, there are alternatives to daily chlorine addition such as SWG and automatic chlorine injection to reduce the daily task. Personally I use the 8 gallon Liquidator as well and purchase 15% liquid chlorine in a 5 gal. containers. Having a small pool, 5 gallons of chlorine will last me more than a month depending on heat and sun load.

 

[richc233]

I thought it was OK to add the Cal-Hypo, and I didn't find anything on the site about it raising PH - I do want to follow the TFP principles as it has been working great for me! I needed some more CH so the increase there was good for me. I just wasn't sure if there was a way to get the TA down so the Cal-Hypo wouldn't affect the PH as much.

Thanks!

 

[jgad]

I use cal-hypo for most of my chlorination. I need the CH since it's cold here and we get an annual mega-dilution with the winter snow melt every year. My annual recipe is to run CH from about 200 (spring) to 350 or 400 over the summer, adding cal-hypo. It's much more convenient than bleach and I want hard water to overwinter with since cold, soft water will eat up a plaster pool.

Forget the dry acid - that's way too expensive. Muriatic acid is what you want - standard 32% concentration (20° baume). Add about a cup for every lb of cal-hypo and you'll be in good shape - test your pH regularly to be sure, of course. As your CH goes up and as the water warms up you'll want to control your pH to keep the SI/CSI near zero.