Pool Saga - Low FC, High pH

[gorocket1981]

Hello,

For another season, the pool saga seems to be started.
I am newbie on the forum and I am trying to learn to have better control on my pool water.

First, if I understand correctly, people on the forum don't seems to trust the tests made in pool store. I don't understand why exactly. For now, it is my only option but to have an higher chance of good results, I do the tests in 2 different pool store and results are almost the same so I suppose that the results are not so bad. I did some search about the test kits. I am planning to purchase a better kit when I find a good kit at an affordable price. I am in Canada so availability and cost are different. But for sure, that is in the plan.

For the past years, I usually put chlorine in the pool using solid form like trichlor and calhypo. With the beginning of this season, after reading many posts here, I consider to convert to liquid chlorine to treat the water instead of other solid form of chlorine. If I understood properly, it is probably the best way to add chlorine. I am also looking to purchase a good and affordable peristaltic pump to have an automated distribution.

My first question is, does the liquid chlorine raise the pH? I read many posts in the forum and I understand that the answer is no. Is that correct? I am asking the question because pH rising is part of my issue and in the past 3 days, I put liquid chlorine and my pH is now too high.

Now lets detail my saga. It is the same issue that I am having each season. At each season I try different things in hoping to have something more stable but I always have the same battle no matter which product I use.
My issue is that each time I am doing a test, the pH is constantly high and Free Chlorine is always below 1 ppm, like 0.4-0.6, which is not enough. Am I just too cheap on chlorine? The issue is that if I put too much trichlor pucks in the chlorinator, I will get too much CYA. If I put too much calhypo, I will eventually get too much CH (and raise pH?). If I put too much liquid chlorine, I understand that I will just add chlorine but will I also raise the pH?

Here is some information of the past days:
My pool is a 43250 Liters pool. My pool is placed in a location so the sun is almost on it all day but the last days were not that sunny. It was mostly cloudy. Water is clear.

My latest test on Sunday morning was:
FC 0.6
CC 0
pH 7.6
TA 39
CH 85
CYA 5
Water temp 60F

So on Sunday, I added 6.2 kg of Alka+. Also, I added 475 g of dry acid. For chlorine, I added 2 trichlor pucks (167 g each) in my chlorinator and set it to half position. I added a puck of calhypo (300 g) in the skimmer. Also, I added 1.5L of liquid chlorine 10.3% in the pool. Don't worry, I didn't buy the trichlor and calhypo pucks. It is remaining from last year.

On Monday and Tuesday evening, I added 1L of liquid chlorine 10.3%

Here is my test result of today:
FC 0.4
CC 0
pH 8.0
TA 142
CH 86
CYA 5
Water temp 60F

So pH rise and there is not enough Free Chlorine. My goal would like to have the pH in the recommended range and always have at least 1-2 ppm of chlorine so water is properly disinfected.
Tonight I added 800g of dry acid and another trichlor puck in the chlorinator and set the chlorinator at 3/4. The 2 previous pucks were not completely dissolved.

Last year I battle all season long with high pH and low chlorine. At this moment, I tried to use trichlor pucks in chlorinator and calhypo 65% pucks in the skimmer to keep a balance between CYA and calcium rising. I was doing shock once a week with calhypo 75%. Maybe I didn't put enough of each for my pool but I was trying to avoid exceeding the correct range for CYA and CH. I was using trichlor as I was told it was lowering the pH. I was also told that calhypo was rising pH. I was expecting a kind of null effect.

So what would be the best solution to have an appropriate FC level and pH level at all time? Is liquid chlorine with the peristaltic pump still the best solution? At the end, does liquid chlorine raise the pH? What do you think?
And side note, I don't want to use salt.

Thanks for your help.

 

[Richard320]

If your CYA is really and truly only 5, that's why you lose a lot of chlorine. The sun gets it all.

You added far too much alkalinity increaser, which is why the pH is climbing. You're going to have to keep adjusting pH down. Each time you lower pH, you also lower TA. The pH comes back up but the TA stays down until you add more via chemicals or in the refill water. Over time, the intervals between adjustments should get longer and the amount of acid needed should decrease. You don't need to raise TA again until it gets to 50. And then only raise it to 70. And that won't be for a few months, most likely.

When the pH gets to 7.8, lower it to 7.2
Raise CYA to 40, then never let the FC dip below 3.

We're aware that test kits are hard to get at a decent price in Canuckistan. You can still get a simple 2-way pH & chlorine tester at Canadian Tire for the daily tests until you can lay hands on a complete test kit.

 

[gorocket1981]

OK. Thanks for your advice.

Is it a normal behavior that because of low CYA the chlorine is eaten that fast by the sun even when there is not much sun? I will get CYA up as you recommended and I hope that I will be able to keep FC level better. I also just bought a solar cover. I will install it over the weekend. Can this help my situation?

I always find it difficult to manage the TA and the pH because of various effect between the two.
So because of the higher TA, the pH is climbing and keep a tendancy to be high? I put 800g of dry acid this evening to reduce the pH. Should I put more? What should be my target for pH and TA for now?

Are you saying that it is normal that the pH will get higher by itself and I will have to reduce it again? Each time I put dry acid, as you said, my TA also goes down. I am probably wrong but I am under the impression that I will soon be too low on TA. If I would use muriatic acid to lower the pH instead of dry acid, would this also lower TA ?

As for chlorine, is it true or not that liquid chlorine raise the pH? If I do like I am planning to and convert to liquid chlorine as my only chlorine source, should I get more pH issues? Do you think it is still recommended if I convert to liquid chlorine like I am considering?

Thanks!

 

[Richard320]

If you have no CYA, you will lose pretty much ALL your chlorine in about an hour of sunlight. With low CYA, it lasts a little longer. A cloudy day means you lose less. A solar cover will help slow the losses a lot, because it blocks the UV.

The TA/pH thing comes from overshooting the TA. Not your fault -- that's what the pool stores recommend. Then you buy more acid. And then more Alkalinity increaser. From them. It's a great business model, for sure. The way to get off the rollercoaster is to stop micromanaging. Seriously, any pH between 7.2 and 7.8 is acceptable. Too many people see 7.7 and rush to lower it to 7.5. That starts the rollercoaster. Same with TA. Let it drop. Some people find a sweet spot where they only have to adjust the pH once a month! Maybe you'll be one of them.

Liquid chlorine is pH neutral. It starts out basic but after it breaks down into salt and chlorine, it ends up neutral.

These questions and more you haven't thought of yet are probably answered in pool school. start with ABCs of Pool Water Chemistry There's an ebook that has pretty much all of it inside that might be worth downloading.

 

[gorocket1981]

Thanks!! It is really appreciated.