Where is all my Cl going?

Jul 16, 2015
10
San Jose
Hello all

New house and a new pool

We inherited a high CH, TA and CYA. I've read around on the site enough (and posted a question) to know that I need to have higher FC because my CYA is high.

Yesterday I put in 4 gallons of 10% liquid Cl,
Today I tested and got the following

7.8 pH
2 FC
140 TA
100 CYA (I diluted the sample 2:1 with tap water and measured 50 ppm)
I also tested CH but the sample never really turned blue, around the 40 drop point it turned clear.

Now all that being said, I recognize I don't have the best test kit for Cl, all I have is DPD, not FAS. That is on order, so I hope to have a clearer picture soon. but I still expected higher FC today.

Thanks in advance for your help.
 
How does your water look? Are you seeing algae, cloudy water, weirdness?

Your CL is being consumed by something...and since your CYA is so high we've got to assume its algae. Not all algae is visible in the water.

You also need to do a 3:1 dilution for a CYA test. You really might be much higher than 100, y'know? I know you're in CA so not sure if any water replacement is possible? But you're going to need a LOT of liquid chlorine to deal with a CYA of 100+
 
Welcome to the forum!

More than ever, over stabilized pools are a FRUSTRATING problem with drought stricken CA. Unfortunately, reduction by water replacements is the only dependable answer unless RO treatment is available to you. If so, it's expensive, but perhaps worth a look, as you are quite likely to have higher than 100 Cya. As asked above, please tell us how the water looks, and what problems your having or have had lately.
 
Thanks all!
I do live in california so draining is not an option. We are getting it resurfaced this winter, so that will be a good reset, but until then I just have to fight it. Couple of things to add;

1) To test the CYA, I first did it per the instructions but got greater than 100. Next I diluted the pool water with tap water 2:1 and then ran the test and got just under 50. Why is that dilution ratio not accurate?

2) The water looks OK, it is not what I would call sparkling maybe slightly cloudy.

3) Is it possible that my test is just wrong and I should wait until I get the better test kit in the mail? Which I will have to do anyway since I will need it to do the Slam.

4) Is it possible that dog hair could cause this? Could that be in the filter (although I recently cleaned it) and absorbing Cl? I have a lab that is always jumping in.

5) I added 4 gallons and got an additional 1 ppm Cl. According to the chart I have to get to 39 to Slam? That seems crazy. And I will have to maintain 12 ppm until I can do a water replacement? That seems crazy too. I know the bio active has caused more issues than it solved, but I don't seem to have a lot of options.
 
I think I may have answered my question with the dog hair...... Maybe I will go to a weekly pump filter cleaning. He is an old boy, so keeping him out of it would be tough.

What about running a simple test, where I clean the filter then add the Cl- to see if it stays there? If it does, then I know what the issue is.
 
Yes, those chlorine numbers are correct. The cloudy water is usually an early sign of an algae bloom. Yes, the dog is likely adding organic material that is consuming chlorine. Making it more important to keep FC around 12.

If the DPD test says 2 then it probably is. But, I'm not sure, I don't have one. I use OTO and FAS/DPD. I am comfortable with your cya reading of 100.

Keep in mind that the PH test is not valid when FC is above 10, so test and adjust when FC drops to 9 or 10.
 
Thanks. I'll clean the filter and keep adding Cl. I don't want to do a slam until I get my test kit (plus I'm out of town this weekend). Should I even worry about the high TA at this point?


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No, TA isn't that high. Just maintain your PH between 7.2 and 7.8. When it gets to 7.8 add muriatic acid to lower it to 7.2. Tjis will slowly lower your TA.
 

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i believe a dog swimming in pool was equal to 20 people in terms of chlorine loss per hour of swimming
i cant find the post now though

If you can find that post, I would like to see it. Not sure about that, certainly not as a given.

The bigger point here, dog or not, is the Cya. When you get into trouble with high Cya, it can be a monster to overcome.
 
Just double checking on your dilution procedure - when you say 2:1, does that mean one part plain water to one part pool water? Or two parts plain water to one part pool water? If the latter, the result needs to be multiplied by 3.
 
In San Jose CA right now I am told you can drain and refil your pool only if you have a leak. We do have a leak in that our skimmer is cracked near the top. As long as I keep the water level a little low (but not too low to cause issues) I don't loose any water. I am hoping that loop hole will let me drain the pool to fix the plumbing. (Also pulling up all the cement and redoing that back yard completely - which would lead to more leaks) At that time I will resurface. We will also be doing this in the winter, hopefully by that time we will have had significant rainfall.

As for the dilution procedure,
I took 5 ml of pool water and mixed with 5 ml of tap water. I then ran the CYA test. I should have wrote 1:1, sorry about that.
 
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