Can't get Chlorine to hold

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
10,744
Northern NJ
Side question: Will the smell of chlorine leave the pool after I let the FC drop to lower levels? My arm smells of chlorine after every test.
Chlorine smell comes from CCs yet your test for CC is 0??

This is an uncovered outdoor pool?

Confirm what test kit you are using.
 

ScubaDoo

Well-known member
Jul 3, 2019
84
Great Lakes
Chlorine smell comes from CCs yet your test for CC is 0??

This is an uncovered outdoor pool?

Confirm what test kit you are using.
Testing with Taylor K-2006. Uncovered outdoor pool. Not a smell to walk around the pool like you were at the community centre pool, but a smell on my arm after diggi g out elbow deep test water.
 

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
11,724
Houston, Texas
Testing with Taylor K-2006. Uncovered outdoor pool. Not a smell to walk around the pool like you were at the community centre pool, but a smell on my arm after diggi g out elbow deep test water.
That smell is the chlorine oxidizing the sweat, dirt, oils, and other micro contaminants on your skin. Try washing your arm with soap before taking a sample and see if you still get a strong chlorine smell on your skin.
 

ScubaDoo

Well-known member
Jul 3, 2019
84
Great Lakes
Sure, let me get the logbook out...

Monday: (started SLAM at 2pm)
It was losing about 5 FC/hour in full sun. But greatly slowed after full sun in evening as well to 0.5-1 FC/hr.

Tuesday:
So losses of 1ppm FC/hour with partial sun on pool in mid morning. Once afternoon hit and the pool gets full sun after lunch it loses about 2-3 FC/hour. Once sun off the pool again in evening it slowed again to 0.5 FC/hour.
 
Last edited:

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
10,744
Northern NJ
Sure, let me get the logbook out...

Monday: (started SLAM at 2pm)
It was losing about 5 FC/hour in full sun. But greatly slowed after full sun in evening as well to 0.5-1 FC/hr.

Tuesday:
So losses of 1ppm FC/hour with partial sun on pool in mid morning. Once afternoon hit and the pool gets full sun after lunch it loses about 2-3 FC/hour. Once sun off the pool again in evening it slowed again to 0.5 FC/hour.
Was that before, after or during your algae problem?

FC loss with algae is not representative of what you should have with a clean pool.

Typical FC loss even in Texas is 2-4 PPM/day.
 

ScubaDoo

Well-known member
Jul 3, 2019
84
Great Lakes
Was that before, after or during your algae problem?

FC loss with algae is not representative of what you should have with a clean pool.

Typical FC loss even in Texas is 2-4 PPM/day.
These are during the current SLAM. Started on Monday afternoon.

Is 2-4PPM/day depend on CYA levels? Do the elevated FC of 12 for SLAM effect loss as well?

Why would the loss be so much in sun, and almost nothing in shade/night?
 

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
11,724
Houston, Texas
CYA protects the FC from premature breakdown due to UV rays. Its like putting on layers on a cold day. Eventually you can put on too many layers and you are so well protected from the cold that your can't move and are basically ineffective. Thats what too much CYA does to chlorine. You will lose some chlorine just due to heat breakdown. That's why we say higher FC loss is normal in summer. We want enough CYA to prevent UV breakdown, but not so much that it binds up FC and renders it ineffective. CYA should be adjusted gradually, 10ppm at a time with about a week wait in between when you are trying to tweek the CYA levels. Tweeking levels only occurs after slam process is completed.

 
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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
10,744
Northern NJ
Is 2-4PPM/day depend on CYA levels?
No. Study the FC/CYA Chart. Look at the difference between the minimum and target FC levels for non-SWG pools. It is always 2-4 ppm. That is the expected daily FC loss regardless of CYA level.

Do the elevated FC of 12 for SLAM effect loss as well?
Yes. Elevated Fc levels lose CL quicker. It is not linear in the amount of FC loss.

Why would the loss be so much in sun, and almost nothing in shade/night?
When you have algae in the pool the sun and heat promote the growth of algae which then uses up FC in the sanitation process. At night you have less algae growth.
 

ScubaDoo

Well-known member
Jul 3, 2019
84
Great Lakes
Ok, good to know.

As an update I've been keeping the SLAM going today just in case. Similar to yesterday so far for morning hourly loss. Not seeing anything on the pool bottom, will keep a keen eye out.
 

ScubaDoo

Well-known member
Jul 3, 2019
84
Great Lakes
Question regarding testing for CC:

Can you do the test if you are only doing a 10mL sample? It doesn't specify, just says add 5 drops of 0003 (not a certain amount for 25 mL or 10 mL)... In the 10mL sample its seems to barely turn it a tiny bit pink (very very very faint).

Or does CC testing need to be done on 25 mL samples only?
 

IceShadow

Gold Supporter
Jun 8, 2019
1,072
Milwaukee, WI
Question regarding testing for CC:

Can you do the test if you are only doing a 10mL sample? It doesn't specify, just says add 5 drops of 0003 (not a certain amount for 25 mL or 10 mL)... In the 10mL sample its seems to barely turn it a tiny bit pink (very very very faint).

Or does CC testing need to be done on 25 mL samples only?
If your 5 drops after doing the FC test only turn it faintly pink then your CC is 0.5 (likely lower, but I record as 0.5 to differentiate from not turning pink at all). :)
 

ScubaDoo

Well-known member
Jul 3, 2019
84
Great Lakes
If your 5 drops after doing the FC test only turn it faintly pink then your CC is 0.5 (likely lower, but I record as 0.5 to differentiate from not turning pink at all). :)
I got two very very faint pink this afternoon. Compared to the bottom white background, more of a off white.

Do you guys ever get a bright pink after 5 drops? I've never seen that yet.
 

ScubaDoo

Well-known member
Jul 3, 2019
84
Great Lakes
I got two very very faint pink this afternoon. Compared to the bottom white background, more of a off white.

Do you guys ever get a bright pink or actual pink after 5 drops? I've never seen that yet.
 

rowiac

Well-known member
Apr 20, 2018
74
Tehama County, CA
The worst CC I have personally seen was 2.0 where it took 4 drops to turn it clear again. But it was still a light pink as opposed to the very dark pink you will get when your FC is high during a SLAM. When doing an FC test, you will see the pink get lighter as you get close to the last drop. The CC test is more like that.
 
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ScubaDoo

Well-known member
Jul 3, 2019
84
Great Lakes
Update:

No overnight loss, two tests so far. All still at FC- 12.0
No CC readings this morning. Which was surprising as I found a drowned mouse in skimmer. (I lately seem to get one after a rain storm. Weird.)
Water clear.

FC holding steady this morning, may be due to the fact it is overcast?