Difficulty maintaining chlorine

May 11, 2015
13
philipsburg, pa
Hi Everyone!

I have a 24ft round AG pool that is 12 years old. I have never had any trouble with it until about 2 years ago. I had problems keeping chlorine in the pool. Over the season I added a very large amount of chlorine, and didn't get a stable reading until the end of the season. Last year, my chlorine reading was high throughout the entire season! This year, I again am not seeing any chlorine readings. My calcium hardness was 295 on initial testing, and the water would only cloud up upon shocking.... it was a mess! I did a partial drain between 1/3 to 1/2 and refill. I cleaned my filter and recharged. The water looks crystal clear and beautiful! BUT, I still cannot get a free chlorine reading. Here are my latest stats:

19,500 gal AG Pool
Vinyl Liner
DE filter
Sat Idx: -0.3
TDS: 800
CYA: 20
Tot Chl: 0.4
Free Chl: 0
pH: 7.3
Tot Alk: 140
Adj Tot Alk: 134
Tot Hard: 194
Copper: 0
Iron: 0
Quat: 3
No Algae

I added 1/4 lb. of pH, 2 lb Stabilizer, 1 bag shock, 3 oz algecide........ No chlorine reading the next day
Added 1 gal clorox.... No reading next day
Added 2 gal clorox....No reading
Added 1 bag shock and 2 gal clorox.....Nothing!

I am beyond frustrated! Why would my readings all be normal, but still not have a chlorine reading? In all my years of pool maintenance, my routine usually consisted of super chlorinating at startup, and shocking when needed...

Help! and Thank you!
 
To begin, welcome to TFP!

Second, take a deep breath. I understand your frustration, but a level head is the only way to get through this.


It looks like the numbers you provided are from a pool store test, which are well known for being inaccurate. I suggest checking out the recommended test kits in Pool School, and going with the TF-100.
The only numbers you can really trust, are the ones you take yourself. Partially because you can control your accuracy, and partially because you aren't trying to drain your bank account like the pool store is.

It also seems like you are playing a guessing game on the chlorine you are adding. If you haven't seen it yet, check out PoolMath to figure out what you should add, as well as what adding it should do.

I'm not an expert, but there's only a few explanations for the 0 reading that I can think of.
1. Inaccurate testing, and the chlorine isn't actually 0 (and possibly too high!)
2. You started with a lower CYA, so it could be burning off the chlorine pretty quick if you are always testing the day after you add. (You added stabilizer, but that can take up to a week to register on a test.)
3. There are organics or ammonia in the pool that are turning the FC to CC quicker than you can dump it in, and either the CC isn't registering properly on the test, or you didn't notice it (you only posted the first set of numbers, so I don't know what the subsequent tests showed, if they are even accurate.)


Additionally, without the concentration % of the clorox you added, we can't accurately know how much actual chlorine was added to the water, same with the shock, which could have contained other things as well (calcium or CYA are the common companions)

You did a good job giving pool info, but it would be better if it were in your signature.
 
Hello Frustrated. While I'm sure a Moderator while chime-in soon, something caught my eye on your comment above .... You appear to be adding chemicals or additives not normally advised by TFP (i.e. bag of shock, algaecide, etc). Typically we're advised to stick with the basics like chlorine, muriatic acid, and/or baking soda - those kind of things. Also, can you clarify where you got your readings? Did you do them yourself or go somewhere? Also, your CYA "may" be a bit low at 20 resulting in the excessive loss of chlorine, but again without knowing how you got those results it's tough to tell. Keep in mind that just because your water appears to be clear and look good, doesn't always mean it's in the best of shape chemically. Finally, before accurate answers can be provided, you should also consider updating your signature to include as much specifics about your pool as possible (for example - see my signature). :) Your reply should help give everyone a little more to go on to provide a good way forward.
 
Welcome to TFP!

You've been given some good advice already. At the top of the list is to get one of the Recommended Test Kits. Water testing is the cornerstone of our approach and informed decisions require accurate test results. As other have stated (and I've experienced), pool store testing or using "all in 1" test strips are often inaccurate and do not provide the precision needed to properly maintain your pool. The purpose of pool store testing is serving as a "loss-leader", meaning that's what gets you into the store so they can sell you all sorts of chemicals and get you to depend on using them on an ongoing basis.

I would also stop the indiscriminate use of algaecides and "shock" products. Liquid bleach in the proper amount is all you need to maintain proper sanitation. Check out the ABC's of Pool Water Chemistry and Recommended Pool Chemicals for more info.
 
Thank you for your quick responses! The numbers posted are the second water analysis done at my local pool store. The first analysis only really differed in the Cal Hardness. I was glad to see that reading come down, and my water does look significantly better! It was very cloudy, and when I added chlorine, it would become cloudier.... My pump was also running inefficiently because I would have to bump it every hour.... Now, since the water exchange and filter cleaning, the pump is running at about 18 psi and steady! My pool place recommended the pH, stabilizer, and 1lb of shock.

I used concentrated regular clorox, 7.?% available chlorine, I believe. I don't want to contribute to increasing my Cal Hardness again, but I had 1 lb of supershock left. I added that and the clorox thinking I would get a "shock level" chlorine reading.

Last evening was the last time I have added anything to my pool... I added 2 gal. clorox.... tested and got a "10" chlorine reading on my strip. Tested this morning, and got "0".
 
Yeah, I can just about guarantee that you could take 5 samples to 5 different stores, or to the same store with 5 different workers, and get 5 different results. Sad but true. No one will care more for your pool and get accurate results than YOU by using one of the recommended test kits (see my signature). In case you haven't done so already, read-up on the pool school info (also in my signature link) and start stocking-up on bleach! It's a great sanitizer with virtually no side-effects to your pool. Doesn't matter where you get the bleach (also seen at pool stores as liquid shock) so shop around for best prices. Just make sure if it's bleach (like Clorox) it's regular and not scented. Some will be 8.25%, others may be 10-12%. I definitely would not put any other chemicals in your pool other than bleach/liquid shock and/or what's recommended by TFP. As for filter PSI - don't get to overly concerned with that either other than making sure you don't have a potential obstruction. By using the recommended test kit, you will have ACCURATE results EVERY time which will allow you to put the correct chemical in your pool. Your #1 priority should be to order the recommended test kit (i.e. TF-100) and stock-up on bleach/liquid shock. :)
 
Thank you so much for your help! I will definitely purchase my own testing system! I did review the poolmath, and according to it, I need 4 gal of clorox.... I'm thinking that since I added stabilizer last saturday, I should wait until the weekend to start anything. I also reviewed the other VERY HELPFUL information! I did not see where I would need algecide? is this another product that is not needed? So interesting and educational!
 
When we, as initial pool owners, walk into a pool store, we think we're getting the best advice possible, and that simply isn't true. Also remember, there is no "quick-fix" solution (algaecide, Pool Perfect, Phosphate reducer, etc) that will make your pool sparkling clean. Once you receive your test kit, you'll armed with all you need. You'll be amazed at how easy it is, and wonder why others continue to stray down that road of ignorance, or relying on the pool store or pool company contract to have someone come to their house. You'll eventually save lots of $$, spend less time maintaining your pool, and enjoy the pool the way it was intended. Happy trails!
 

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While you wait, I highly suggest reading through everything in Pool School on this site. It will help you take control of your pool better than any pool store employee ever could.

I've been with it for less than a month, and converted one neighbor and one family member to the TFP method, because they are so impressed with what I managed to do with my new (to me) pool in the span of about 2 weeks.
 
Welcome to TFP! Congrats on getting a great test kit! We would hate to see it turn green also!

The most important step to stop your pool from turning green is to keep your chlorine level above the minimum for your CYA at all times. If it drops below the minimum algae can start to grow. Chlorine CYA Chart

Keep 3 to 4ppm of chlorine in your pool until the test kit arrives.

Here are some of my fave Pool School articles in case you missed any of them.
TFPC for Beginners
ABC's of Pool Water Chemistry

Here are the Recommended Levels for your pool.
Here is the Water Balance for a saltwater pool.
Here are the Recommended Pool Chemicals and how to add them.
Use PoolMath to figure out how much to add.
 
Last edited:
Hi all!
I received my testing kit this weekend and wow! what a setup! Here were my stats after adding 4 gal. bleach to my pool:

FC 4.8
CC 0.6
pH 7.4
TA 100
CH 240
CYA 50
Index -0.5

I tested the chlorine yesterday, and had the following:

FC 0.6
CC 0.2

I added 2 gal of bleach last pm. This should bring the FC up to around 4-5. My question is, should I take it back to shock level or maintain the FC at 4-6?

Thank you all for your help!
 
Congrats on taking control of your own testing! You won't regret it. It's very empowering and good to know YOU are in control. As for when to stop SLAMming .. remember the golden rule(s):
A. CC is 0.5 or lower
B. You pass an OCLT (ie overnight FC loss test shows a loss of 1.0 ppm or less);
C. And the water is clear.

After all 3 are met, you can let the FC levels drop to normal.

So if you are still working on any of those, keep at it. Looks like you are very close though. :)
 
Thank you for your response! One last question (yea, right!) :D

Once these conditions are met, do I keep the FC at maintenance level, or do I need to "shock" on a weekly basis? I guess I'm not sure how to maintain once balanced. I am used to the many years of pool store advice, and I maintained by dipping a strip and shocking on a weekly or bi-weekly basis. I would think I could keep the FC level up and check the CC/FC/pH on a regular basis?
 
Keep the pH between 7.4 and 7.8 (only add acid when you get a pH above 7.8) and always keep your FC above the minimum value for your current CYA level. Daily test for pH and TC with the color match block test. Weekly check FC/CC using FAS-DPD test, alkalinity if you've been adjusting pH. CYA and CH only if you have a water replacement or monthly to check things out. No need to shock weekly if you're maintaining proper pH and FC levels. I haven't shocked my pool since last spring, when I took over the pool and dealt with an ammonia issue from previous owner.
 
Welcome to the forum Frustrated...

The TPFC method, put simply, is adding to your pool only what is needed. As JVTrain stated, testing is absolutely necessary. You should test pH and FC/CC daily with the others at less frequent times (weekly, monthly, etc...). As you get more familiar with your pool, you'll begin to see it's patterns. X amount of bleach every day, Y amount of muriatic acid every week (or whatever time period).

If you keep your FC within the recommended range based on your CYA, you should never have an algae bloom and never any need to SLAM.
 

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