Trouble Maintaining Chlorine and Stabilizer

[xxkylexx]

Hello TFP community,

We had our pool built ~1 year ago. The family has really been enjoying it this past season. I have never owned a pool before, so this has all been a learning experience for me. I stubbled across this website now in an attempt to take matters into my own hands after the pool store couldn't seem to help me with water chemistry issues.

Ever since this past spring (and to date), I have been having problems with maintaining chlorine levels. According to pool store testing (and my own test strips), my chlorine levels have always eventually been going to 0. I have the SWG, which I originally thought would mean I wouldn't ever have this problem. The pool store consistently suggests that my CYA is low and I need to add more stabilizer, then shock the pool with multiple gallons of liquid chlorine, and that should allow my SWG to "catch up". I have been doing a constant dance of this process, rinse and repeat, for the past 6 months or so. After adding ~20 pounds of stabilizer over the past several months, and with my SWG set to 100%, my chlorine levels continue to go to 0 after the "shock" process normalizes. At this point, "the boss/expert" at the pool store tells me she hasn't ever seen this problem in her 20 years of taking care of pools and has no answers for me. Needless to say, I am a bit frustrated and now am looking for my own answers, which has brought me to TFP.

I ordered the TF-100 kit, have read over the pool school articles, and am eager to get this problem sorted.

The TF-100 kit came in today and I ran all the tests this evening in my kitchen. Here are the results:

• FC - 1.5ppm. It was almost completely clear after 2 drops, with a small hint of pink, but I added the third to get it 100% clear.
• CC - 0.5ppm. Same here. After adding back the 5 drops of R-0003, it was very faintly pink. I added one drop of R-0871 and it was completely clear.
• CH - Not sure I did this test correctly. The water turned red after adding the 3 drops of R-0011L, however, after 30 drops of R-0012 (which would be 750+ ppm) I still wasn't seeing the color turn blue so I just stopped. If I tried hard, it kind of seemed like it started to turn a bit purple. Maybe I should try again? The pool store tests (for what it's worth) have consistently indicated that CH was in an acceptable range, so I think I am just doing something wrong here.
• TA - 50
• CYA - <20ppm. I filled the viewing tube up all the way, it started to get a little cloudy, but I could still see the black dot at the bottom of the tube.
• PH - 7.6
• Salt - I had a hard time with this test too. I bought the Taylor test strips and thought that maybe it showed something in between 2000-3000, but it wasn't very clear to me. Again, my SWG and Intelliconnect system do not indicate a salt level issue so I am not sure this is correct. Pool store tests in the past have always showed this in acceptable range as well (~3500). I did add a bag of salt back in the summer when my SWG indicated it was getting low.
• For fun, I did the K-1000 test. Man, it is really hard to read the yellow chlorine colors on this one! My best guess was maybe 2 ppm, which I guess lines up with the earlier FC test?

Some other observations/info:

• The pool water has always looked crystal clear. Never had any green water or anything like that.
• The pump runs for 12 hours /day, 7am - 7pm.
• I thought that maybe I had a leak somewhere that was depleting my CYA, but I turned off the autofill for the past week and have not noticed the water level really changing at all. Also, salt levels have always read good, so if I had a leak I would think that would go down too.
• We haven't had much rain for the past couple months like we do in the early summer, so I don't think that is diluting my CYA.
• I last added ~3-4 lbs of stabilizer maybe 3 weeks ago. Looks like I am at nothing now.
• SWG has been at 100% since this problem started in the spring.
• I thought that maybe something was wrong with my SWG, but the pool builder came out and did a "bucket test" and tells me that it is producing as expected.
• I don't really brush the pool that often since it always looks fine, but from what I read now, it seems that I should be doing this weekly regardless? Not sure if that has contributed to this problem.
• Per the pool builder instructions, I have been cleaning the cartridge filters and SWG every ~3 months.
• Per the pool builder instructions (and pool store), I have been adding Jack's Magic Magenta Stuff sequestering agent, ~6oz weekly.

Thanks in advance for any help!

 

[Casey]

Welcome to TFP. We're heading into the slow season so sit tight until others pop in to help. Some questions i and others may have are:

Are you on well water or city water?
Have you been using bagged calcium hypochlorite?
Can you post a full panel of Test results with the TF100?

You need to follow the SLAM procedure to a T.

 

[TampaKathy]

For the CH, you may have to follow the "Fading endpoint" method. That's what I have to use. Read this: Calcium Hardness
Here's the important part of the article:

• The sample may turn purple during the test, or go to blue for a moment and then turn back to red/pink. This is called a “fading endpoint” and is caused by interference from metal ions. If this happens, do the test again, but this time add five drops of R-0012 before adding any R-0010 or R-0011L. Remember to count the initial five drops in the total.
  In extreme cases, a fading endpoint may occur even when adding five drops of R-0012 at the start. If that happens, mix pool water with an equal quantity of distilled water, test that, and then multiply the result by two.

 

[xxkylexx]

Welcome to TFP. We're heading into the slow season so sit tight until others pop in to help. Some questions i and others may have are:

Are you on well water or city water?
Have you been using bagged calcium hypochlorite?
Can you post a full panel of Test results with the TF100?

You need to follow the SLAM procedure to a T.

- I have city water
- No, just the SWG and liquid chlorine jugs from the pool store.
- I posted them above in my original post (with some commentary since this was my first time). Did I miss something?

 

[Casey]

- I have city water
- No, just the SWG and liquid chlorine jugs from the pool store.
- I posted them above in my original post (with some commentary since this was my first time). Did I miss something?

You're good. I missed it.

 

[Bperry]

- I have city water
- No, just the SWG and liquid chlorine jugs from the pool store.
- I posted them above in my original post (with some commentary since this was my first time). Did I miss something?

What's the reason for adding the magenta stuff? If your CYA level really is below 20 then that's a likely reason why you can't keep chlorine in the water. You may want to check the FC level, add enough liquid chlorine to increase the level to 5ppm and then check the FC again in an hour to figure out if you are calculating the correct amounts of stabilizer, etc and make sure the pool volume is accurate.

 

[xxkylexx]

What's the reason for adding the magenta stuff?

I am not sure. It's just what the pool builder instructed me to do during the hand-off. And the pool store also suggested it so I figured it was necessary. I thought it was something that was suppose to protect the plaster finish from staining. Maybe we're past that period now? Should I stop?

If your CYA level really is below 20 then that's a likely reason why you can't keep chlorine in the water.

That's what I have been told as well, but the problem seems to be I cannot maintain CYA levels. I have added 20+ lbs of stabilizer over this past spring and summer in an attempt to achieve the CYA levels originally suggested by the pool store, but it keeps going down, along with my chlorine. I just added 3-4 lbs about three weeks ago, which according to the product bag is enough to raise my CYA levels by 40-50 ppm, and here we are with a CYA test back to < 20. Now that I have my own test kit, should I try adding ~4 lbs and see what happens and monitor? I just don't want to keep wasting this stuff if there is some other problem that needs to be addressed first.

 

[Casey]

With a diminishing CYA and chlorine consumption, you may have ammonia. I would add enough FC to bring it up to 10ppm and check it and then recheck it in a half hour to see where the FC is. If it diminishes quickly, that could be your problem even if the water is clear. You could stop at a pet store and buy an ammonia kit to check it or see if they can check it for you.

Are you having to replace any water from loss?

Pool stores are notorious for throwing Crud at the customer to boost sales. We call that being pool stored.

I'd check for ammonia build up since your CYA keeps dropping. If it is ammonia, you'll need enough chlorine to overcome it by SLAM'ing the pool.

 

[xxkylexx]

With a diminishing CYA and chlorine consumption, you may have ammonia.

I go have three little boys that swim daily over the late spring through summer and early fall, so it wouldn't surprise me if lots of bodily fluids have been making it's way into the pool

I would add enough FC to bring it up to 10ppm and check it and then recheck it in a half hour to see where the FC is. If it diminishes quickly, that could be your problem even if the water is clear.

I will try it this evening and see what I find. Maybe the Overnight FC Loss Test (OCLT) too?

 

[TampaKathy]

I believe you can ask the pool store to test your water for metals...such as copper and iron. I know I have iron but I am on a well. So I will need to use sequestrant regularly. I have read that PB's or plaster companies put it in at start-up just in case you have metals. I bought a test kit at Lowe's to test for iron...I am going to try to remember to ask the pool store to test for it when I go in next time just to see if they get the same result. You should probably test for metals before you stop using it.

 

[Bperry]

I am not sure. It's just what the pool builder instructed me to do during the hand-off. And the pool store also suggested it so I figured it was necessary. I thought it was something that was suppose to protect the plaster finish from staining. Maybe we're past that period now? Should I stop?


That's what I have been told as well, but the problem seems to be I cannot maintain CYA levels. I have added 20+ lbs of stabilizer over this past spring and summer in an attempt to achieve the CYA levels originally suggested by the pool store, but it keeps going down, along with my chlorine. I just added 3-4 lbs about three weeks ago, which according to the product bag is enough to raise my CYA levels by 40-50 ppm, and here we are with a CYA test back to < 20. Now that I have my own test kit, should I try adding ~4 lbs and see what happens and monitor? I just don't want to keep wasting this stuff if there is some other problem that needs to be addressed first.

Just to rule it out. Can you post a picture of how you are doing the CYA test? The water for that test needs to be room temperature. Mix 1/2 pool water with 1/2 test reagent and shake well for 60 seconds. Also make sure you are looking down through the tube and not through the side. Might also add a picture of what stabilizer you are adding.

Don’t put in any more CYA until you know what’s going on.

 

[Auburn02]

Pool stores are notorious for throwing Crud at the customer to boost sales. We call that being pool stored.

I was actually impressed that this pool store told him "raise CYA, use liquid chlorine" - seems pretty okay to me, but then I read about the "magic" stuff.

If the test results are accurate, I'm at a loss but interested to see what turns up. Even if CYA were in fact 0, I still wouldn't think that would justify this much chlorine loss. I don't know the exact numbers but surely running an IC40 at 100% for 12 hours a day should more than make up for whatever FC would be lost in a day, right? Looking forward to what an OCLT reveals (with the SWG turned off).

 

[Bperry]

I was actually impressed that this pool store told him "raise CYA, use liquid chlorine" - seems pretty okay to me, but then I read about the "magic" stuff.

If the test results are accurate, I'm at a loss but interested to see what turns up. Even if CYA were in fact 0, I still wouldn't think that would justify this much chlorine loss. I don't know the exact numbers but surely running an IC40 at 100% for 12 hours a day should more than make up for whatever FC would be lost in a day, right? Looking forward to what an OCLT reveals (with the SWG turned off).

If there is ammonia, that can consume CYA and FC quite quickly from what I’ve read. I’d for sure stop adding the jacks stuff but I don’t know enough about it to say anything other than it seems to only be useful if you have some kind of metal staining. Adding it on a regular basis seems unnecessary at best and can cause weird problems at the worst. Someone who knows more about that would have to answer.

But definitely stick with the liquid chlorine only for a few days and try and get a measurable FC number above 5ppm using the Taylor test kit.

 

[xxkylexx]

Adjusted PH down to 7.3 in preparation for a SLAM. I only have 2 gallons of liquid chlorine on hand today, so with my CYA at < 20, I thought a SLAM FC target of 10 ppm might be enough? I got mixed results on researching if I should attempt to raise my CYA to 30 before the SLAM, but decided to just leave it be for now. I'll have to run to the pool store in the morning to get some more liquid chlorine.

PH - 7.3
FC - 1
CC - 0.5

It was cloudy out today, so I went ahead and got started. Turned off my SWG and set my pump to run 24/7. Brushed the pool.

4:30pm
Added 1 gallon of 10.5% liquid chlorine in attempt to bring my FC from 1 to 10.

Gets dark here at ~5:45pm now.

6:40pm
FC - 7
CC - 0.5

Added 5.3 cups of 10.5% liquid chlorine in attempt to bring my FC from 7 to 10.

7:40pm
FC - 8.5

Added 2.4 cups of 10.5% liquid chlorine in attempt to bring my FC from 8.5 to 10.

8:30pm
FC - 9

Rounded up on pool math and added 2 cups (instead of 1.75) of 10.5% liquid chlorine in attempt to bring my FC from 9 to 10.

10pm
FC - 8

Added 3.5 cups of 10.5% liquid chlorine in attempt to bring my FC from 8 to 10.

Will check again in the morning. Should I keep going with the 10ppm FC SLAM or should I reset and change something?

 

[mknauss]

What you are doing is fine. At this time of year, the CYA level of 30 ppm is not as critical as the sun is not as intense on the pool water surface. However, if you see large FC drops during the day, then less at night, then adding some more CYA will help that.

 

[Bperry]

What you are doing is fine. At this time of year, the CYA level of 30 ppm is not as critical as the sun is not as intense on the pool water surface. However, if you see large FC drops during the day, then less at night, then adding some more CYA will help that.

If the OP has added 20lbs of stabilizer over the season and 3-4 lbs a few weeks ago, is there some other issue causing the CYA to read low?

 

[mknauss]

To have used that much stabilizer the pool either overflows significant volumes often, due to rain, or there is a leak.

 

[xxkylexx]

I topped things off at 10pm to get the FC back up to 10 again. Did a test this morning at 6:30am and FC is at 6.5, so a 3.5 loss overnight. I added what liquid chlorine I had left (1.66 cups) to bring it to 7.5 ppm. Will head out to the store here soon to grab some more so I can try to maintain a FC level of 10 over the weekend.

 

[Bperry]

I topped things off at 10pm to get the FC back up to 10 again. Did a test this morning at 6:30am and FC is at 6.5, so a 3.5 loss overnight. I added what liquid chlorine I had left (1.66 cups) to bring it to 7.5 ppm. Will head out to the store here soon to grab some more so I can try to maintain a FC level of 10 over the weekend.

Did you test after you added chlorine last night? Looking at your log, none of your expected additions actually bring it up to the expected level. Are you sure about your pool volume? You might check that by doing a pH test and seeing if it reacts to acid addition as the app calculates it.

Also make sure the auto full stays off.

 

[xxkylexx]

How long do I need to wait after adding chlorine to test? Don’t I need to wait for it to mix with the pool water for a little while to get an accurate reading? I am just going off of the pole volume number given to me by the builder. From what I read, PH testing is probably not accurate right now during the SLAM process? I did some simple math based off my pool dimensions and average depth and it appears that 11.7k gallons is in the ballpark, at least.

Autofill has been off for about a week now. No change in water level. Will leave it off.

Just loaded up with 10 gallons of liquid chlorine, so I think I am set for a while now . I am going to up my FC target to 12 to stay on the safe side