Help!!! Cloudy with Dropping Chlorine

[aeh0603]

Thanks for the reply. I’ve thought about that. But if there was some mustard algae or some other stubborn algae remaining after a SLAM, wouldn’t that cause the OCLT to fail?

No, it would not. The OCLT is not a definitive test if you pass. It's only definitive if you fail, that's why there are 3 criteria to end a SLAM.

That said, if you read the instructions for mustard algae you need to pass all 3 criteria of a regular SLAM before elevating FC to the mustard SLAM level for 24 hrs.

 

[jecomer]

No, it would not. The OCLT is not a definitive test if you pass. It's only definitive if you fail, that's why there are 3 criteria to end a SLAM.

That said, if you read the instructions for mustard algae you need to pass all 3 criteria of a regular SLAM before elevating FC to the mustard SLAM level for 24 hrs.

I will do some reading on mustard algae. Thanks!

 

[lazygirl1978]

I'm also kind of skeptical of your SWCG. How old is it? It sounds to me like it's not keeping up, which could be contributing to your problems. It takes awhile for the SWCG to make the chlorine, so I keep liquid chlorine around and, after any heavy use of the pool, add a couple cups so that the SWCG doesn't fall behind. (It makes me feel like my father, back in the 80s, throwing in bags of shock after a pool party.) But I haven't had to SLAM the pool yet (it's just a year old). It just sounds like your chlorine output just hasn't been reliable, so I wonder if your generator is getting old?

 

[jecomer]

I'm also kind of skeptical of your SWCG. How old is it? It sounds to me like it's not keeping up, which could be contributing to your problems. It takes awhile for the SWCG to make the chlorine, so I keep liquid chlorine around and, after any heavy use of the pool, add a couple cups so that the SWCG doesn't fall behind. (It makes me feel like my father, back in the 80s, throwing in bags of shock after a pool party.) But I haven't had to SLAM the pool yet (it's just a year old). It just sounds like your chlorine output just hasn't been reliable, so I wonder if your generator is getting old?

Thanks so much for the reply! I have thought about the SWCG as a potential issue. But here's my rationalization why it is not. Let me know your thoughts. I have been holding the chlorine levels much higher than suggested (TFP suggested min 4 and target 6). Most recently, I have been holding around 11. This last time, when the pool started crashing (i.e. the chlorine levels started rapidly dropping and the pool started to get cloudy), the chlorine level when I detected the issue was 5.5, which is in between the suggested min chlorine level and target (my CYA at the time was 75 to 80). Using this information, I would assume that my pool should not be "crashing" with a chlorine level of 5.5. Therefore, I am assuming my SWCG is working properly and there is some algae.

My plan right now is to attack the issue like I have mustard algae. As soon as I pass all three criteria of the SLAM, I am going to take the FC to the mustard algae shock level for at least 24 hours. And then I'm going to cross my fingers!!!

To answer your questions, I believe my SWCG is 4 or 5 years old. But about two years ago I had the cell replaced under warranty because it was showing some signs of damage/degradation. Any chance you know the typical life span of a SWCG? That is a great suggestion about using liquid chlorine after heavy usage. It has crossed my mind, but I have never done that. If I can ever get this pool stable, I will definitely start using that technique.

Thanks again for your input. Please let me know if you have any other ideas or suggestions.

 

[mariane]

Maybe I'm missing something here.
1. Your CYA at 55 means FC range is 7-9. Letting it get down to 5 is low and will allow algae to grow. Shock level is 22.
2. Reading an earlier post it looks like the CYA and FC levels were "yoyoing". Are you keeping them consistent with pool math?
3. A SLAM is not a SLAM unless you keep the FC shock levels constant and add more liquid chlorine to keep the FC at shock levels. That usually takes at least a day or two or more. I don't see in your posts you doing the SLAM correctly. That could be part of the problem. At CYA of 55, your shock level is 22. Did I miss that you kept this level through out the day? And hold it there till it did not drop and 0 CC? Only then is it time to do a OCLT.

 

[jecomer]

Maybe I'm missing something here.
1. Your CYA at 55 means FC range is 7-9. Letting it get down to 5 is low and will allow algae to grow. Shock level is 22.
2. Reading an earlier post it looks like the CYA and FC levels were "yoyoing". Are you keeping them consistent with pool math?
3. A SLAM is not a SLAM unless you keep the FC shock levels constant and add more liquid chlorine to keep the FC at shock levels. That usually takes at least a day or two or more. I don't see in your posts you doing the SLAM correctly. That could be part of the problem. At CYA of 55, your shock level is 22. Did I miss that you kept this level through out the day? And hold it there till it did not drop and 0 CC? Only then is it time to do a OCLT.

Thanks so much for your reply. In my initial post, in this thread, I obviously presented a lot of data. But that being said, I left a lot out. I did not provide all the data for the multiple readings and chlorine additions I did daily during the SLAM. But yes, during the SLAM, I tried to maintain the chlorine levels at or above the recommended shock levels. I believe that SLAM took approximately 4 days to satisfy all three SLAM criteria. Also, I looked back through my notes and I do not think the FC ever got as low as 5. I believe the lowest it got was 7.5 before it appeared the algae was winning and I decided to start the SLAM. As far as the potential yo-yoing, I have been trying to keep my FC above 10 since the start of this pool season. And the FC does not seem to drop (yo-yo) until I have what appears to be an algae bloom and the pool becomes cloudy. At that point, the SWCG can not keep up with the demand and the FC keeps dropping. The issue I have seen is that it appears my CYA is not holding like I would expect. It appears to be dropping much quicker than the 5 ppm per month that Texas Splash mentioned is typical. That being said, I have started monitoring the CYA much more frequently and adjusting as necessary. That's why I was very surprised when the pool/chlorine started crashing this time when I was holding FC levels around 11 and the CYA was 75 or 80. I hope I answered all your questions and potential concerns. Please let me know if you have any other ideas or suggestions. Thanks again!

 

[jecomer]

No, it would not. The OCLT is not a definitive test if you pass. It's only definitive if you fail, that's why there are 3 criteria to end a SLAM.

That said, if you read the instructions for mustard algae you need to pass all 3 criteria of a regular SLAM before elevating FC to the mustard SLAM level for 24 hrs.

So as of early this morning, I passed the OCLT overnight and therefore, the SLAM is complete. The water is crystal clear, the CC is 0 and the OCLT was 0.4. Actually, I tested it twice this morning. The first test the OCLT was 0.0 and the second was 0.4. That all being said, I added chlorine to the pool to take the FC to Mustard Algae Shock levels. Based on my CYA being 75-80, my FC target level was 44. After adding the chlorine, I brushed the heck out of the pool, clean the pool toys and I watched the sun come up. After all that, I checked the FC levels and I slightly overshot and the FC was 52.

At this point, I am planning monitoring the FC levels and keeping it at or above 44. I am also planning on brushing the pool a couple more times, along with the skimmer, steps, bench, etc. So do I only need to hold this level for 24 hours? At that point am I done? Do I need to do anything else other than cross my fingers? Do I need to clean the cartridge filter? I cleaned it a couple days ago during the SLAM.

Thanks so much for all your help and please let know if I've missed anything.

 

[mknauss]

Hold the elevated MA SLAM FC level for 24 hours.
Then maintain the FC at the elevated maintenance level for a month or so. I assume you have read the Mustard Algae article.

 

[jecomer]

Hold the elevated MA SLAM FC level for 24 hours.
Then maintain the FC at the elevated maintenance level for a month or so. I assume you have read the Mustard Algae article.

I read this article.

Mustard Algae

Is this the one you were referring to? Let me know if you have additional articles that would be useful.

Also, what were you referring to when you mentioned "elevated maintenance level"? Were you referring to the elevated levels, FC around 11, I was holding prior to this SLAM or is there an elevated maintenance level suggestion that I missed in my research?

Thanks again for all your help!

 

[mknauss]

That is the correct article. Embedded in it is a link to the CYA/FC chart for Yel/MA FC levels. Essentially, the minimum is 15% of CYA to hold for an extended period of time. With your SWCG, if you can maintain a steady FC, you should target about 17.5% of CYA.
FYI - you will not be able to test pH during that time.

 

[jecomer]

That is the correct article. Embedded in it is a link to the CYA/FC chart for Yel/MA FC levels. Essentially, the minimum is 15% of CYA to hold for an extended period of time. With your SWCG, if you can maintain a steady FC, you should target about 17.5% of CYA.
FYI - you will not be able to test pH during that time.

Thank you so much! I've only seen the FC/CYA levels presented in the simplified and standardized versions, I've never seen the levels presented in this chart:

Chlorine CYA Chart

So based on this chart and my CYA levels of 75 to 80, my Mustard Algae shock level is 46 (60% of 80) and my Mustard Algae min level is 12 (15% of 80). Based on my reading and research, I have never seen the Mustard Algae min level referenced anywhere else other than this chart. I use the Pool Math for my day to day calculations and it is not referenced on there. In your first reply this morning, you mentioned holding the Mustard Algae min level for a month or so. Is this suggestion referenced anywhere? I'm not questioning your information, I simply want to follow up by reading/researching for myself. As soon as I think I've got this pool maintenance figured out, I quickly learn how much I don't know. Thanks again for all your help. This was very helpful!

 

[jecomer]

That is the correct article. Embedded in it is a link to the CYA/FC chart for Yel/MA FC levels. Essentially, the minimum is 15% of CYA to hold for an extended period of time. With your SWCG, if you can maintain a steady FC, you should target about 17.5% of CYA.
FYI - you will not be able to test pH during that time.

Sorry, one more question. I forgot to ask where the target FC level of 17.5% of my CYA came from? Thanks again!

 

[jecomer]

Sorry, one more question. I forgot to ask where the target FC level of 17.5% of my CYA came from? Thanks again!

I may have answered my own question. Is the bump from 15% to 17.5% for the reserve FC in this reference?

"A minimum FC level is needed as a "reserve" for usage so in practice at least 2 ppm FC is required even at low CYA levels. The table above shows the amount needed for disinfecting chlorine for equivalent killing power (rates), but does not take into account the amount needed in reserve to prevent getting used up as this varies by pool."

 

[mknauss]

That article used to state holding MA FC levels higher for a period of time, as I remember.

Up to you. If you have truly had MA, I would hold the elevated FC levels for awhile to be sure it does not come back.
The 17.5% is just to give you a little buffer, as you post above. Same as SWCG FC minimum is 5% of CYA, but target is 7.5%.

 

[jecomer]

That is the correct article. Embedded in it is a link to the CYA/FC chart for Yel/MA FC levels. Essentially, the minimum is 15% of CYA to hold for an extended period of time. With your SWCG, if you can maintain a steady FC, you should target about 17.5% of CYA.
FYI - you will not be able to test pH during that time.

Just a quick update and question. It has been a little over a week since I completed the SLAM and the Mustard Algae Shock. The free chlorine levels have come down and I have been holding them around 15 ppm. With my current CYA level of 70, I'm trying to stay above 17.5% or 12.25 ppm. The kids have been swimming for several days and the water looks great. I actually did another OCLT a couple nights ago and the result was 0.

That said, I have done some research on testing for pH with high chlorine levels. Historically, I have had an issue with my pH drifting upwards rather quickly. Therefore, I hate to ignore the pH and not test and adjust during this period when I am holding the chlorine at these higher levels. Based on my research, it appears there are a few options. Obviously, I could purchase a pH meter. I am holding out on this as a last resort. Another option, that was suggested by a couple of respected members, is that you could dilute the pool sample with distilled water. I haven't had a chance to pickup any distilled water yet. The last option is from the following video by Taylor and involves reducing the chlorine levels by adding a drop of R-0007 to a 50 ml pool water sample.

Taylor pH Test Interference

Out of curiosity, I checked the pH with straight pool water and then with 1 drop of R-0007. Both samples yielded the same result of 7.8. So the question now is, with the elevated chlorine levels, do I treat the pool with this result or just wait the month or so until I bring the chlorine levels back down under 10? Also, what are your thoughts on the distilled water option?

Again, I really appreciate all your input and help with this issue.

 

[Texas Splash]

While we generally use an FC of 10 as the baseline for FC influence on pH testing, there's not a whole lot of pH difference between an FC of 10 and 12, so if you let the FC fall to 12 you should be close enough to a good pH reading. Now if your FC was 14, or more, I might be hesitant to trust the pH reading as a false/temp high.

 

[jecomer]

Update...the chlorine has crashed, yet again. And the wife is interviewing pool companies as we speak.

Like my initial post, sorry it is so long. I'm just trying to provide all the relevant information I can think of.

So just to bring everyone up to date, I completed the last SLAM (the one that started this thread) on May 16th and I immediately did the mustard algae shock. The pool looked great. As recommended, I held the FC levels around 15.0 +/- 2.5 until last Sunday, July 5th. This was a little longer than suggested, but because of the history of the chlorine crashing, I was hesitant to lower the chlorine to suggested levels too quickly. For the past couple weeks, we have received a lot of rain and I have had to drain a few inches from the pool probably 3 or 4 times. I have carefully monitored the chemical levels over the past 2 months, especially the FC, CC and CYA.

Yesterday, I checked the FC and it had dropped from 12.0 (on 7/5) to 6.5 (on 7/12). I did not change anything other than the fact that it had rained quite a bit. I anticipated the FC to be slightly lower, but not this much. At first glance, you would think, based on the recommended levels, 6.5 is still just fine, but I could see just an ever so slight hint of cloudiness. I set the SWCG to 100% (from 80%) and ran it an extra 3 hours last night. I also checked all the chemical levels.

FC 6.5
CC 0.0
pH 7.6
CYA 55
Salt 3500
TA 65
CH 400

Based on the rain, I had anticipated the CYA and salt to be a little low and I added stabilizer and salt. This morning I checked the FC and it had dropped even further to 2.0. I immediately started another SLAM.

I just don't get it. Based on CYA of 55, my FC was above the recommended level (6.325) and well above the min (4.125). What am I doing wrong? What is causing my FC to crash? I am at my wits end and I am running out of ideas. These are probably a stretch, but here's some possibilities that I could think of:

1. SWCG - First, the SWCG has held the FC levels stable at 15.0 +/- 2.5 for almost the past 2 months. But I did check to make sure it is working this morning and it appears to be functioning fine. Or at least when I checked it.
2. Salt - From what I can tell, the ideal salt level for my SWCG is 4000 with a min of 3000. I typically try to keep it right at or just below 4000. Yesterday, the salt level was 3500 and I added 40 lbs which should have brought it up to approximately 3800 (I have not tested it yet). That being said, the SWCG control panel frequently displays the message "Low Salt or Low Temperature", including this morning. The low salt light has not illuminated, just the message.
3. CYA - The CYA testing is obviously subjective. So maybe I am testing incorrectly or my interpretation of when the black dot disappears is way off. For example, lets say that when I read the CYA at 55 yesterday, it was actually 80. That would mean the min FC would be 6.0 and the recommended FC level would be 9.2. I think this is a long shot, but it is something I've considered.

I can not think of anything else. Again, any help would be greatly appreciated. Thanks!

 

[mknauss]

Your signature shows a SWCG as Aquapure Ei. Jandy has Aquapure 700 or 1400 or the Truclear/Ei. Which do you have?

CYA dropping can create sudden spikes of FC loss. With a SWCG, there is almost a breakover point. At 70 CYA, you may be fine, but at 60 CYA your FC loss spikes. My pool is that way. As you get rain, it is imperative you test CYA at least monthly. And keep it at 70 - 80 ppm.

 

[mknauss]

"Low Salt or Low Temperature"

Check on that. Is that with pump running? Is your filter clean so your flow switch is closed for the SWCG?

 

[mariane]

mknauss is great.
I'm not sure I understand if you are adding chlorine daily, or if you're using SWG exclusively and running 24/7 (I don't have a SWG and don't know if you're supposed to run it 24/7. If I'm wrong, you can ignore me.
When you write "the FC crash" do you mean the FC levels won't stay at 6.5 when you are running the SWG 24/7? Are you adding chlorine daily?