Question about chlorine lock

Bkmomof4

Bronze Supporter
Sep 20, 2015
12
0
York pa
#1
Re: Chlorine Lock Causes?

I am also having an issue with chlorine. Last year we could not keep the chlorine level high enough to show up on a test. The CYA levels were fine. This year we drained some of the water but still cannot get a chlorine reading to last more than a couple hours. What do you suggest?

Finally got my test kit. Result from yesterday are:
CYA 80
FC 7 (after adding 2gal bleach)
CC 2.5
ph 7.5
TA 180
CH 400

This morning the readings were:
FC .5
CC 2

The water is crystal clear and there is no algae. Do we need to keep the chlorine level at 6 as stated in the chart for it to be safe to swim in?
 

Richard320

LifeTime Supporter
TFP Expert
Jan 6, 2010
20,322
1
San Dimas, CA (LA County)
#2
Something's eating your chlorine. It's either organics or sunlight.

Organics include things like leaves and twigs, algae, and the A-word: Ammonia.

A seriously green pool will devour chlorine like nobody's business, but you ought to be showing something on the test if you checked it within an hour of adding chlorine. A pool with Ammonia makes a green pool look anorexic. It'll eliminate chlorine as fast as you can pour it in the water.

The place to start is with some test results. Also, tell us where they came from (what kit) and what kind of pool and equipment you have, and what the water looks like.
 

duraleigh

Admin
Mod Squad
LifeTime Supporter
Platinum Supporter
TFP Expert
In The Industry
Apr 1, 2007
31,266
3
Sebring, Florida
tftestkits.net
#5
bkmomof4,

Welcome to the forum.

As you continue to read, you will find that we teach that you take the bull by the horns and learn to manage your pool. In short, "Stay out of the Pool Store"

Anyone talking with you about chlorine lock is either terribly under educated or simply doesn't want to learn.

Chlorine Lock is a myth that doesn't exist. If you decide to learn what we teach here at TFP, we will promise you will end up with crystal clear water and a whole new understanding of how this all works

You will find it increasingly difficult to follow our advice and then follow pool store advice as well. The two simply don't mix well.
 

Kiss4aFrog

LifeTime Supporter
TFP Guide
May 22, 2013
2,723
0
Hudson, WI
#6
Welcome to TFP Bkmomof4 :wave:

Chlorine lock should end up on myth busters so it can be debunked. IMHO, It's something the pool store person will say when they don't know what's going on. Usually followed by a 30 to 60 bottle of "try this".

A photo of the water would be helpful as would adding your pools and equipment information in your signature as outlined here: Pool School - Getting Started

The more information we have the more accurate and helpful the response ;)

As stated above it's more likely something is eating your chlorine. Need to know your CYA level and what you are using for a chlorinator and if it's your test results or you are having the pool store test for you.

:testresults:
 

Bkmomof4

Bronze Supporter
Sep 20, 2015
12
0
York pa
#7
Re: Chlorine Lock Causes?

Finally got my test kit in the mail. Results from yesterday are:
CYA 80
FC 7 (after adding 2gals bleach)
CC 2.5
ph 7.5
CH 400
TA 180

This morning results were
CC .5
CC 2

the water is crystal clear and no algae. Do I need to keep the chlorine level at 6 as stated on the chart in order for the water to be safe for swimming?
 

RobbieH

LifeTime Supporter
TFP Expert
Aug 30, 2010
4,052
0
52
Dallas, TX
#8
Check your math... CC of .5 and CC of 2 at the same time? I think you mean FC of 2 and CC of .5. If you had an FC of 7 last night and FC of 2 today, you have something organic growing in your pool. Was your initial FC of 7 taken near dusk, or earlier in the day?
 

tim5055

Mod Squad
LifeTime Supporter
TFP Expert
May 11, 2014
10,085
1
Franklin, NC
www.title-3.com
#9
Check your math... CC of .5 and CC of 2 at the same time? I think you mean FC of 2 and CC of .5. If you had an FC of 7 last night and FC of 2 today, you have something organic growing in your pool. Was your initial FC of 7 taken near dusk, or earlier in the day?
Agreed. Just because water is clear doesn't mean something isn't growing in it sight unseen. I had clear water last year after an oops on my part that was consuming 3ppm FC overnight...
 

Bkmomof4

Bronze Supporter
Sep 20, 2015
12
0
York pa
#12
Per the chart I'd need to reach a 31 chlorine level to slam. My CYA is 80. Probably not realistic. There is no visible algae growth. Is it safe to swim in?
 

RobbieH

LifeTime Supporter
TFP Expert
Aug 30, 2010
4,052
0
52
Dallas, TX
#13
Per the chart I'd need to reach a 31 chlorine level to slam. My CYA is 80. Probably not realistic. There is no visible algae growth. Is it safe to swim in?
Do you mean it is not realistic to fix the issue?

Personally, I will not swim in a pool that will not hold FC, or one that has algae.
 

jblizzle

Mod Squad
LifeTime Supporter
TFP Expert
May 19, 2010
41,193
4
Tucson, AZ
#14
Why is that not realistic? That is exactly what you need to do until you pass the 3 criteria to stop. You are currently only passing 1 of them.
 

ping

LifeTime Supporter
TFP Expert
Jun 24, 2011
2,923
0
51
Long Beach, CA
#15
You have nascent algae. There is just enough chlorine being added to keep the algae from blooming, but not enough chlorine to kill off all the algae.

Believe me, you need to complete the SLAM process or you will go through 10 times more chlorine than you should. Been there done that.
 

RobbieH

LifeTime Supporter
TFP Expert
Aug 30, 2010
4,052
0
52
Dallas, TX
#16
You have nascent algae. There is just enough chlorine being added to keep the algae from blooming, but not enough chlorine to kill off all the algae.

Believe me, you need to complete the SLAM process or you will go through 10 times more chlorine than you should. Been there done that.
We all have learned this the hard way at least once I think. :)
 

Richard320

LifeTime Supporter
TFP Expert
Jan 6, 2010
20,322
1
San Dimas, CA (LA County)
#17
Per the chart I'd need to reach a 31 chlorine level to slam. My CYA is 80. Probably not realistic. There is no visible algae growth. Is it safe to swim in?
Just a thought... have you added any non-chlorine "shock"? That's stuff like Chlor-free and Oxone. MPS will give a false high CC reading.

If the pH is in range and the FC is above minimum for the CYA level, then technically I guess the pool is safe to swim in. People have been swimming in rivers and lakes and ponds with no test results for centuries and haven't been dying from it. But if that CC is CC and not interference, expect skin irritation and burning eyes.

Taking FC up to 31 is not so difficult. It's just a matter of emptying some jugs. If you get a good kill on whatever is growing -- and it can't be much if the water is clear -- then maintaining it shouldn't take any huge volume of bleach. It's just getting it up there initially that looks so daunting. And if it does have an unquenchable thirst for bleach, then it's just a matter of time before the pool turns to a swamp.

Also check for algae lurking behind lights and stairs and inside ladders. You still haven't filled out your signature so we have no clue what we're dealing with.
 

Bkmomof4

Bronze Supporter
Sep 20, 2015
12
0
York pa
#20
I have been slamming since Tuesday. This morning(Saturday) my FC had a 2.5 loss overnight and the CC was 1.5. I followed the prep instructions to the letter. I have added at least 40 gallons of bleach. Am I doing something wrong? This seems extreme considering the water looked good before I started.