CH question after asorbic acid treatment

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frank2020

Member
Apr 28, 2020
9
North Carolina
Pool Size
15000
Surface
Fiberglass
Chlorine
Liquid Chlorine
Question
I did an absorbic acid treatment all stains are gone. I’m one week out from starting to add chlorine back. TA 70 PH 7.2 FC 3 CH 70
My question is when to start adding the CH back do I wait till the 2 weeks is up from the asborbic acid treatment since my FC is not holding yet and start add it when the FC is back to normal? Thxs for any insight.
 
I'm a bit confused, too. Did you drain and refill after the AA treatment?

Anyway, as Maddie said, get chlorine settled first. And if you just refilled, also make sure you have CYA in the water. And FC of course following the FC/CYA Levels.
 
CH is the abbreviation we use for calcium.

Are you asking about adding calcium or chlorine to your pool?

We use FC as the abbreviation for chlorine to not have this confusion.
 
YippeeSkippy said:
No rush on the calcium. Get the chlorine settled first, then deal with calcium.

Maddie :flower:
Click to expand...
Question I’m a week and some days out from starting to add chlorine back after the absorbic acid treatment all the levels are good now. But I can’t get the water clear. I have been doing the slam procedure for 4 days now and the water is cloudy but you can see the bottom of the pool. I have been adding the chlorine at night to get it to the 16 level the software asks for. Yesterday was the first time the FC level was at 6 when I checked it from the day before and today it was 4.5.previously it would be .2-.5 when I checked it. Do you think it’s just a case of weather along with the abosbic acid that may have still been in the water. We have had rain and storms for the last week and have had inches of rain. I just wasn’t sure if it’s just simply keep up the slam procedure until the water is clear or I was maybe missing something. Thank s I’ll leave tonight reading below.
TA 90
PH 7.4 ( FC @ 4.5 when tested)
FC 4.5
CYA 45
CH 220
 
mgtfp said:
I am still very confused about what you have done. Could you please give us a step-by-step list?
Click to expand...
1. Did asorbic acid treatment as outlined in the forum on site here.
a. Lower PH to 7.2
b. Take FC to zero
c. Add AA
d. Add Jacks Magic Blue Stuff as needed
e. Waited Two weeks and started the process to add chlorine back.
f. Slowly started adding chloride for 3 days
e. Last 5 days have been adding chlorine per the slam method since water was slightly cloudy and the and chlorine level was dropping from 16 to .2-.4 in 24 hours.
g. Last two days chlorine has held at 6 & 4.5 in 24 hours from 16 (the pool math app is saying to have it at for slam)
h. Changed to new filter (cartridge)3 days ago

I hope you can understand this easier. The only other thing is the rain we have had severe storms with 6-10 inches of rain in the last 10 days.
 
What I'm not understanding is how your CH got from 70 to 220? Have you added any calcium increaser? And was it always at 70? Was the pool freshly filled?

2 weeks without chlorine is a long time. Our wiki article on the AA treatment says that you can start adding chlorine after 24 hours. Just don't SLAM for at least 2 weeks:

Ascorbic Acid Treatment - Further Reading

www.troublefreepool.com www.troublefreepool.com

How long has your pH been low?
 

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mgtfp said:
What I'm not understanding is how your CH got from 70 to 220? Have you added any calcium increaser? And was it always at 70? Was the pool freshly filled?

2 weeks without chlorine is a long time. Our wiki article on the AA treatment says that you can start adding chlorine after 24 hours. Just don't SLAM for at least 2 weeks:

Ascorbic Acid Treatment - Further Reading

www.troublefreepool.com www.troublefreepool.com

How long has your pH been low?
Click to expand...
I think that one time was a bad reading. I re checked it 4 times since and the CH is at 200 after I add es 8lbs to get it to the 200.
No the pool was not refilled.


Ok well I guess I read that wrong. So yes 2 weeks with no chlorine and then I started adding it again.
 
Have you done an OCLT? The loss over 24h does sound a bit much, but without confirmation that you actually reached 16ppm it's hard to tell how much you actually lost to potential algae. The AA seems to be neutralized again.

Your CYA test was 45, if I remember correctly? Generally round up to the next 10 for the purpose of determining FC values, do SLAM would be 20. But I'd still prefer avoid going there that short after the AA treatment.

I'd suggest to do a proper OCLT. Dose up to 16ppm after sunset, confirm the FC level after 30 min with the pump running. Then test again in the morning before sunrise after having the pump run for at least 30min (you can let the pump run over night to avoid having to get up even earlier). If the loss is more than 1ppm you'll definitely have to SLALM.
If you pass the OCLT, but the water is still cloudy,, You should also SLAM.

In your case after the AA I'd suggest to go a bit gentler, and maybe only go half way up to SLAM. Clearing will take longer, but the risk of the stains returning will be smaller. Looks like you have been able to go up to 16 without stains returning, do that might be be a good compromise for now. Maybe don't go up to the real SLAM of 20, not just because of FC, also because of pH, that goes temporarily up when adding that much Chlorine (it goes down again as the chlorine is used up). It's the combination of high FC and high pH that is most critical for stains.

Make sure that your pH doesn't get too high. Anytime you're under FC 10, check pH. Before dosing up to 16, bring pH down to 7.2.

Check TA also, it will drop when adding acid frequently. Don't let it fall below 50, but don't add baking soda sooner. Then bring it back to 80 or so.

Let's hope that the stains don't return while getting the pool back in shape.
 
You will also notice after an AA treatment, that when you do finally add in chlorine, that your FC will drop pretty quickly from the target you tried to reach. This is because the AA in the pool will neutralize the chlorine, and the chlorine will also neutralize the AA. So until all the AA is gone through that balancing act, you will go through chlorine -more- than you might anticipate. That doesn't necessarily mean you have algae or organics, it could be the AA neutralizing the chlorine and vice versa.

But 2 weeks without any chlorine, yikes! What's the weather been like and temps?! And was any Polyquat-60 added when you did the AA treatment? Just curious about that.
 
frank2020 said:
I think that one time was a bad reading. I re checked it 4 times since and the CH is at 200 after I add es 8lbs to get it to the 200.
Click to expand...

So, you did add 8lbs of calcium chloride to increase CH to the 200ppm that it is now? Before adding those 8lbs, CH must have been somewhere around 150ppm, but this was wrongly tested as 70ppm?
 
jesse-99 said:
You will also notice after an AA treatment, that when you do finally add in chlorine, that your FC will drop pretty quickly from the target you tried to reach
Click to expand...

Not quite sure how to put Frank's observation into perspective, I haven't done a real AA treatment, only a small one on the overflow spa where I just dumped the water and didn't go through the joy of having to neutralize the AA. You have probably better experience there.


Frank said:

frank2020 said:
e. Last 5 days have been adding chlorine per the slam method since water was slightly cloudy and the and chlorine level was dropping from 16 to .2-.4 in 24 hours.
g. Last two days chlorine has held at 6 & 4.5 in 24 hours from 16 (the pool math app is saying to have it at for slam)
Click to expand...

There still is something eating the chlorine. My guess is that residual AA would take FC further down, and the observed chlorine loss is probably due to algae. A proper OCLT would help to quantify the actual night time loss better.

What are your thoughts? Could this chlorine loss still be AA? I just think that after 2 weeks with no chlorine at all, there is no way that there's no algae in the pool.
 
@mgtfp Yep. Hard to say exactly, that's why I asked about whether Polyquat-60 was used. Hard to believe there isn't an algae bloom when a pool goes 2 weeks without chlorine (though I might believe it depending on a) conditions, and b) use of Polyquat-60. That said, agreed that OCLT is important to determine what's going on and it -could- be a combination of both the AA neutralizing -and- algae. The good news is, the AA will soon enough get neutralized by the chlorine additions, and then he will know for sure if he's still losing FC in an OCLT that it's algae. And if it's cloudy, then it's very likely algae (and maybe some FC loss due to the neutralizing piece).

BTW, you remember 3 years ago helping me with my first real questions here at TFP? LOL. I still do! I've come a long way! (and yet so much to learn).
 
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jesse-99 said:
BTW, you remember 3 years ago helping me with my first real questions here at TFP? LOL. I still do! I've come a long way! (and yet so much to learn).
Click to expand...

I surely do. Great pool. And you've really come a long way, certainly turning into a stain removal expert. I'm sure you'd prefer not having to turn into a stain removal expert, but what can you do...
 
  • Haha
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jesse-99 said:
You will also notice after an AA treatment, that when you do finally add in chlorine, that your FC will drop pretty quickly from the target you tried to reach. This is because the AA in the pool will neutralize the chlorine, and the chlorine will also neutralize the AA. So until all the AA is gone through that balancing act, you will go through chlorine -more- than you might anticipate. That doesn't necessarily mean you have algae or organics, it could be the AA neutralizing the chlorine and vice versa.

But 2 weeks without any chlorine, yikes! What's the weather been like and temps?! And was any Polyquat-60 added when you did the AA treatment? Just curious about that
Click to expand...
mgtfp said:
So, you did add 8lbs of calcium chloride to increase CH to the 200ppm that it is now? Before adding those 8lbs, CH must have been somewhere around 150ppm, but this was wrongly tested as 70ppm?
Click to expand...
Yes that’s correct as I retested 3 times after adding the 8 lbs and got 200 each time.
 
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