Where is my chlorine going?

[Watermom]

We'll need a little more info to be able to help. Post current water testing results (FC, CC, TC, PH, alk, Calcium hardness, cya) and what type of kit you tested with. Also, tell what type and volume your pool is and exactly what all you have added to your pool. (Ingredients, not just "shock", etc.) Then somebody here can take a look and hopefully help you figure out what is going on.

[vanman2501]

My numbers are
TH - 20
FC - 0
PH - 7.5
TA - 120
CYA - 45
I have used a few different testing kits the HTH test kit, the HTH test strips and another liquid test kit the I can't remember the name of. All have the same readings
I have a 24' round 52" deep above ground pool.
I use borax, baking soda, liquid bleach and chlorine tablet.
Since I changed to using these products I have never had a problem until this year.

vanman2501

[Watermom]

In a pool this size, each quart of 6% bleach should raise your cl by about 1 ppm. How much bleach at a time are you adding and how often? Go ahead and add 6 quarts (1.5 gallons) and that should take you up to 6ppm. What type of chlorine tablets are you using?

[vanman2501]

I use pro-care 3" pucks
I was adding one and a half gallons then went to 2 gallons and then went up to 3 gallons and I'm back to one and a half gallons. No matter how much I added I always end up at zero in the morning. I just added one and a half gallons so I see what happens in the morning again.

vanman2501

[tonyl]

You might have your water tested for phosphates. If they are 3000ppm+ as I suspect, it will consume the chlorine quite rapidly. I've been there and have to treat every 3 years or so. Not many people have this problem, but phosphates build up in my pool and I find it impossible to keep chlorine in the water more than a few hours when I let them go. Sounds like that's what you have going on to me.....I use ALUM when it gets that high, kinda messy...have to vacuum to waste after treating but it's effective.

Hope this helps, Tony

[CarlD]

I'm sorry but this is a VERY simple problem. Something is consuming your chlorine and you have to KILL it.

You need to shock your pool (with bleach) up to 15ppm of Free Chlorine (FC). You have 13,500 gallons. That means you need to add 3.5 gallons of Ultra bleach to get it to about 15ppm. Or you can add 4 gallons of regular bleach.

But you have to do it. Then, 3x a day, check that the FC is still in the 12-15 range. If not, each gallon of Ultra will add 4.4ppm and each gallon of regular will add 3.9ppm.

You need lots of bleach and lots of P.O.P.P.--Pool Owner Patience & Persistence.

You have absolutely NO reason to suspect or treat phosphates. Phosphates are the LAST test you do, when you have exhausted all the other steps. But you need to start with the first one--you have something you MUST destroy so you can maintain your chlorine levels. I've told you how to do it. It's not easy, but it IS simple.

[tonyl]

No need to be sorry, it IS a simple problem and we both agree that "something is consuming your chlorine."

I was simply sharing my situation relative to phosphate buildup that I've experienced several times in the last 9-10 years of pool ownership. I could have shocked for weeks and the problem wouldn't have gone away. Like vanman, I was unable to maintain chlorine leve within the pool. And this situation repeated itself AFTER installing a SWG (chlorine level 100ppm within the cell) virtually eliminating routine shocking.

Your assertion that "you have absolutely NO reason to suspect or treat phosphates" is not clear for me, considering I advised he 'might have his phosphates checked", and it's exactly what I've experienced with my own pool the last decade.

Given my history, what harm could be done by a free phosphate test?