Am I using too much liquid chlorine, not enough?

[ejs873]

This is my first summer using only liquid chlorine. It has been hot and sunny almost every day and I am adding about 32oz of chlorine every day. Is that about normal? I add 16-32oz of MA weekly also to get the PH down. I am fine with adding that much chlorine, just wondering if that is average during the summer. Still cheaper than a pool guy!

My PH usually runs high - close to 8
CYA is about 50 now
The morning after a full sunny day my FC is around 1. After adding the 32oz is bumps up to about 3-4.
Never had any algae problems or cloudy water

 

[mas985]

With a CYA of 50, you should not allow the FC to get below 4 ppm. Target range is 6-8 ppm.

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

By running the FC so low, you may have a low grade algae bloom that is consuming CL so it is best to run within recommendations even though you may not see any problems.

 

[thetekgeek]

32 oz of what concentration? According to PoolMath, 32 oz of 12.5% will raise FC by 2.8 in 11k gallons.

That is probably ok under normal circumstances. However, you said your FC is 1 in the morning. CYA is 50. That is asking for a problem. You need to be following this chart: Chlorine / CYA Chart - Trouble Free Pool

With a CYA of 50, you should never let your FC fall below 4. You are below 4 even after you add the 32 oz. You should add enough bleach to get your FC to 8 and then run an OCLT - Perform the Overnight FC Loss Test (OCLT) - Trouble Free Pool

I suspect you might have an algae bloom on the horizon. If you fail the OCLT, you will need to perform a SLAM - SLAM - Shock Level and Maintain - Trouble Free Pool

 

[ejs873]

That makes sense. However, with liquid it burns off so fast here that there would be no way to maintain 8 without adding multiple times a day. Is that what people are doing? I use 10% liquid chlorine. In the winter I was able to get away with adding half a gallon maybe once a week without any issues. Clearly not the same in the summer.

 

[poolnovice1]

I use a DE scoop to add my chlorine. I add 3 scoops of 12.5% liquid chlorine every evening to maintain 6-7ppm at 50 cya. I think a DE scoop holds 48 fl oz.

 

[ejs873]

I use a DE scoop to add my chlorine. I add 3 scoops of 12.5% liquid chlorine every evening to maintain 6-7ppm at 50 cya. I think a DE scoop holds 48 fl oz.

so you are adding just over a gallon every day. If your pool is basically double mine, a half gallon is what I will try and see what happens. I have been adding 32oz every day and no issues yet. Its been 90s and sunny here for at least a month.

 

[clambert1273]

That makes sense. However, with liquid it burns off so fast here that there would be no way to maintain 8 without adding multiple times a day. Is that what people are doing?

well I have harsher weather than you but I can tell you what I do for mine using liquid right now, My CYA is 60 so I looked up my target which is 7-9 and my min is 5 so I dosed my pool to around 10 one morning and let it sit until next morning then tested to see how much I lost in 24 hours that gave me info to see how I could keep it above 5 all the time. My sweet spot is adding 1/2 gal of 10% twice a day once in morning and once around 7-8pm and usually by my test at 9am I am holding 5.5 - 7FC

now my routine will change when I can fire up my swg again

 

[MITBeta]

However, with liquid it burns off so fast here that there would be no way to maintain 8 without adding multiple times a day.

I don't think you will find that this is true if your CYA reading is correct.

- Add enough to get your FC up to 8 tonight and then test again tomorrow night.
- If your usage seems high tomorrow, run the Overnight Chlorine Loss Test.
- If you fail the OCLT, run a quick SLAM Process.
- Otherwise, dial up your CYA another 10ppm and follow the FC/CYA Levels.

 

[poolnovice1]

That makes sense. However, with liquid it burns off so fast here that there would be no way to maintain 8 without adding multiple times a day. Is that what people are doing? I use 10% liquid chlorine. In the winter I was able to get away with adding half a gallon maybe once a week without any issues. Clearly not the same in the summer.

It shouldn't burn off any faster just because it's liquid. The CYA in the pool should prevent it from getting burned off. Also I just weighed my DE cup with chlorine. I was pretty close -- it's 40 oz. So I'm adding 120 oz daily in the summer.

It definitely works. I have 0 cc and have not shocked my pool in a year.

 

[Oly]

Before I installed my SWG, I dosed my pool with liquid chlorine every evening after sunset to avoid any losses through the night.
My CYA was 40ppm and my daily 24 hour FC loss averages 2.5 maybe 3ppm at peak summer.
I dosed every evening with enough liquid to match my expected FC loss and never let my FC drop (even 23 hours after dosing) below the low target number for a CYA of 40 which is 5ppm.

 

[ejs873]

I am not sure if the Pool Math app is wrong or something else. I checked this morning and the FC was 0.4, PH 8 and CYA 45. The app said to add 64oz of chlorine and 16oz of MA. I did and then checked 4 hrs later. FC was 2.8. So either that math is wrong or it is burning off faster than the FC is rising. Like I said, I have never had any algae issues at all and the water is crystal clear, but these numbers don't make any sense to me. If having the FC that low in the mornings is truly an issue, why have I not seen any negative effects? I want to make sure the pool is balanced correctly and to me it seems to be. I am going to check it again later tonight and see how far it has dropped from the 2.8.

 

[clambert1273]

I am not sure if the Pool Math app is wrong or something else. I checked this morning and the FC was 0.4, PH 8 and CYA 45. The app said to add 64oz of chlorine and 16oz of MA. I did and then checked 4 hrs later. FC was 2.8. So either that math is wrong or it is burning off faster than the FC is rising. Like I said, I have never had any algae issues at all and the water is crystal clear, but these numbers don't make any sense to me. If having the FC that low in the mornings is truly an issue, why have I not seen any negative effects? I want to make sure the pool is balanced correctly and to me it seems to be. I am going to check it again later tonight and see how far it has dropped from the 2.8.

It could be a couple things pool size wrong or chlorine is weaker thAn label. Best way to get accurate on either of those is to add what it says & test about 30 min later and see how far off it is then you can play with data

 

[ejs873]

It could be a couple things pool size wrong or chlorine is weaker thAn label. Best way to get accurate on either of those is to add what it says & test about 30 min later and see how far off it is then you can play with data

Thats a good idea, Ill try that. I was thinking that I needed to wait until the water fully cycled to check levels. I hope the chlorine isnt weak, its pretty new and I loaded up for summer!

 

[clambert1273]

Thats a good idea, Ill try that. I was thinking that I needed to wait until the water fully cycled to check levels. I hope the chlorine isnt weak, its pretty new and I loaded up for summer!

Na 30 min should be ok, when im seeing disparity thats what I do then go to effects of adding and start playing with percentage and/or size to see what equals the amount I did get to

 

[MITBeta]

What FC value were you shooting for? I just tried putting 0.5FC, 45CYA and 10% Bleach into the PoolMath app and get a recommendation of 91oz for 6ppm. You really should be rounding CYA up to 50 and targeting 8-9ppm.

Have you run the Overnight Chlorine Loss Test yet?

 

[ejs873]

What FC value were you shooting for? I just tried putting 0.5FC, 45CYA and 10% Bleach into the PoolMath app and get a recommendation of 91oz for 6ppm. You really should be rounding CYA up to 50 and targeting 8-9ppm.

Have you run the Overnight Chlorine Loss Test yet?

When I bump the CYA up to 50, the app uses my 0.4 FC and automatically puts in a target FC of 6. Changing the CYA to 50 raised the chlorine to 77oz. It just seems odd that adding 64oz only took me from 0.4 to 2.8. Maybe I waited too long to re-test and it burned off. Was sunny and 97 yesterday.

 

[JJ_Tex]

I would look at the chart in my signature. For a CYA of 50, your target FC is 6-8. That is what you want your water to be the majority of the day, so feel free to shoot for 9 or 10 so that it drifts down. Dosing to 6 means you drop below the target FC as soon as you are done adding the chlorine and dangerously close to the minimum FC level (4).

Speaking of, I am also a bit worried that you have a slight algae issue since your FC has been well below 4 on several occasions. Algae is present in the water well before it starts becoming visible, so an OCLT is the only true way to know if it is there.

I would also test 30 mins after taking it up to FC of 9 or 10, that way you can be sure the chlorine is as strong as advertised. If it is not, the easy solution is to add more

 

[ejs873]

I will do the OCLT tonight to verify. When they say FAS-DPD test, that is just the FC test in my K-2006 test kit, correct?

You are in the same area as me, do you use close to a gallon a day of chlorine? Is that a realistic amount?

 

[JJ_Tex]

I will do the OCLT tonight to verify. When they say FAS-DPD test, that is just the FC test in my K-2006 test kit, correct?

You are in the same area as me, do you use close to a gallon a day of chlorine? Is that a realistic amount?

On the FAS-DPD, I have the TF100 kit, but it is the powder you dissolve then use the drops to make it clear. I believe it is the same process on the K-2006.

I have salt water, so I only use liquid chlorine when I need to quickly add chlorine (pool parties, had the SWCG set too low, etc.). I have my SWCG set to make ~4 FC per day and that has been working fine for me the last few weeks. If yours is also using 4 FC a day, that would be about half a gallon of 10% chlorine per day.

A gallon of 10% liquid chlorine in your pool will add FC of 9. Either your chlorine is weaker than advertised, or you have algae burning up the chlorine as well (even if you cant see it).

 

[ejs873]

On the FAS-DPD, I have the TF100 kit, but it is the powder you dissolve then use the drops to make it clear. I believe it is the same process on the K-2006.

I have salt water, so I only use liquid chlorine when I need to quickly add chlorine (pool parties, had the SWCG set too low, etc.). I have my SWCG set to make ~4 FC per day and that has been working fine for me the last few weeks. If yours is also using 4 FC a day, that would be about half a gallon of 10% chlorine per day.

A gallon of 10% liquid chlorine in your pool will add FC of 9. Either your chlorine is weaker than advertised, or you have algae burning up the chlorine as well (even if you cant see it).

Sounds good, ill do that test tonight. That would explain why i cant get the FC up even with adding all that chlorine yesterday. Thanks!