Question about chlorine level

[kmandeville]

Hi all,

Thanks for all your help so far. My levels are almost where I want them. TA is about 50. pH is low at 7.0 (Going to raise that today probably). CYA is 40.

I've been adding liquid chlorine nightly lately. Last night I added some. This morning my FC is at 5. It's on the low side. I know some will burn off today (it's going to be 90 today and 97 tomorrow). My question is, if we're going to be using the pool today, should I just leave it at 5 for today and add extra tonight? Or should I add some this morning before people use it, to raise it closer to 7+?

CC is 0, btw so that's good

 

[Chasarms]

If it were me, I’d add now. You could easily be at 1 by tonight with use and UV loss.

 

[mknauss]

Follow the FC/CYA Levels.

 

[kmandeville]

I thought I was. I know 5 is on the low side of the optimal levels. My question was, should I raise it some more now so it's not depleted by tonight? Or just let it drop throughout the day, and replenish tonight? It's my first year with the pool. And I've just started using liquid chlorine instead of the tabs in a floater.

Follow the FC/CYA Levels.

 

[mknauss]

If your FC loss each day is 2-4 ppm, when you add your liquid chorine, you need to add enough to ensure the FC never goes below minimum before you add chlorine again.

So if you believe you will have a high use / high FC loss day, add more chlorine now.

At the end of the day, you NEVER want your FC to drop below minimum.

 

[kmandeville]

Thanks, that's what I was trying to figure out. I want to start the day potentially higher than the 7 range so it will drop down into the optimal range, not below it. thank you!

 

[Jimrahbe]

K,

I would add it now.. Does not hurt to be on the high end and depending on who will be in the pool, you might need it..

Thanks,

Jim R.

 

[PoolNewb2020]

Thanks, that's what I was trying to figure out. I want to start the day potentially higher than the 7 range so it will drop down into the optimal range, not below it. thank you!

With manual dosing the FC level will bounce up and down every day, unless you want to add chlorine multiple times a day.
That is why it is recommended to add to the high side, in your case 7ppm, so that in the next 24h the FC will drop to around 4ppm, which is still below the minimum, not because it's an optimal level.

In your OP you said you added some chlorine, but didn't say how much. What ppm did you target? Sounds like you thought the ppm should've been higher in the morning based on you addition.

 

[CrystalRiver]

As long as your FC is below SLAM level and you can see the bottom of the deep end, it's safe to swim. You can comfortably raise the FC level this morning, even a bit above the target range, in anticipation of burnoff. The most important thing is that it never, ever drops below minimum.

 

[kmandeville]

So I've been adding about 2.5 cups each night based on the bottle saying that's what you should add to a stabilized pool, and I've been measuring in the mornings. Today, I measured the chlorine at night, it had dropped to about 2.6 ppm I believe. Based on some calculation I looked up that said 1.3 ounces of chlorine to raise 10,000 gallon pool 1 ppm. Tonight I added 4 cups trying to raise it to the high level 7 or 8ppm since it's been super hot the past few days and we've had 6 people in the pool for many hours each day. I just never seem to get it above 5 in the mornings when I measure. Combined chlorine is 0 and water is pretty clear. .
I raised the pH from 7 to I think 7.8 (too far. I tried to target raising it to 7.6 but it went too far). Calcium hardness is 60. TA is 50. CYA is 40-50

 

[PoolNewb2020]

Are you using pool math to calculate how much liquid chlorine to add? Sounds to me like you are guessing.
Looking at your logs you've been adding 20oz, 10oz or so, which is way too little.

Your target FC for CYA of 50ppm should be 8ppm. So each morning when you do your measurnments, enter whatever FC you get into pool math and target 8ppm. It will tell you exactly how much to add to reach this target.

 

[kmandeville]

Are you using pool math to calculate how much liquid chlorine to add? Sounds to me like you are guessing.
Looking at your logs you've been adding 20oz, 10oz or so, which is way too little.

Your target FC for CYA of 50ppm should be 8ppm. So each morning when you do your measurnments, enter whatever FC you get into pool math and target 8ppm. It will tell you exactly how much to add to reach this target.

Ok thanks I didn't realize the pool math app would tell me. I have been somewhat guessing. Thanks!

 

[kmandeville]

Are you using pool math to calculate how much liquid chlorine to add? Sounds to me like you are guessing.
Looking at your logs you've been adding 20oz, 10oz or so, which is way too little.

Your target FC for CYA of 50ppm should be 8ppm. So each morning when you do your measurnments, enter whatever FC you get into pool math and target 8ppm. It will tell you exactly how much to add to reach this target.

So I use the "Effects of Adding" option? According to that, if I'm choosing the right sanitizer option (bleach - I'm adding 10% liquid chlorine - I have to check the bottle), it says I have to add like 40+ ounces to raise the FC just 3 ppm. I'm going to go through a lot more bottles of chlorine than I expected!

 

[kmandeville]

I looked it up. I'm using 10% sodium hypochlorite which is just bleach. I'll try to start following what the Effects of Adding option recommends to increase my FC levels. I'm just about at 7 now (6.9) so I added 2.5 cups to bring it to a little above 8. Thanks for all the help!

For people who put in chlorine by hand daily, do you test your FC daily? I got replacement solutions for my test kit but I could see going through several replacements through end of August

 

[PoolNewb2020]

You can use effects of adding, but I find it easier to use the overview screen. Just touch on FC and it will bring you to the calculator. The nice thing about this option, which could be used for PH, TA, CYA etc. is that it will take into account other variables that you have measured and it shows target ppm. Also, once the calculation is done, there is an option at the bottom of the page to log the addition right from there. So you don't need to get out of that screen and into creating a new log screen.

 

[kmandeville]

You can use effects of adding, but I find it easier to use the overview screen. Just touch on FC and it will bring you to the calculator. The nice thing about this option, which could be used for PH, TA, CYA etc. is that it will take into account other variables that you have measured and it shows target ppm. Also, once the calculation is done, there is an option at the bottom of the page to log the addition right from there. So you don't need to get out of that screen and into creating a new log screen.

OMG, that's awesome, I didn't see that! Thank you!