Help!!! Cloudy with Dropping Chlorine

[jecomer]

Please help! My wife is threatening to hire a pool service. I have been a long time follower, but this is my first post. First off, let me warn you, this is a long post. If I’ve learned anything from hours of reading these forums, you guys need as much information as possible to try and help out. So here we go…

We live in Orlando, Florida and have a 15,000 gallon, in ground, plaster with quartz, salt water pool. We have owned our home for almost seven years and this is our first pool. I have struggled with keeping the pool stable from the beginning. Obviously, there was a learning curve at first, but for the past several years, with the help of this group, I feel like I actually know what I’m doing. Essentially, I can not keep the chlorine from crashing. This has happened so many times that now I can visually see when it starts to happen. The water will go from crystal clear to slightly milky/cloudy. When this happens, the free chlorine levels will start dropping. Even if I bump up the chlorine production to 100%, the free chlorine levels keep dropping and the pool gets more milky/cloudy. At this point, I typically start the SLAM process. This scenario seems to repeat every two to three weeks, when I have the pool open (beginning of March through the beginning November). Note that when we “close” the pool, we simply turn off the pool heater. I still monitor the levels, just not quite as frequent.

As for the cloudy water and dropping chlorine, I have tried everything I can think of. Two years ago, our local pool store said that there was an excessive amount of nitrates in the pool and this was feeding algae in the pool. After SLAMming the pool, I tried holding the free chlorine levels a little higher (7-8 ppm) than suggested. This still did not work, so I completely drained the pool and did a thorough cleaning. The pool seemed to be a bit more stable. But here I am two years later and I still can not keep the chlorine levels from crashing every two to three weeks.

This pool season I have tried holding the free chlorine levels even higher. After SLAMming the pool, I have been trying to hold the free chlorine levels around 10 to 11 ppm. Even though the pool has been used more than usual (Covid-19 stay at home orders with six kids), the pool has looked great for the past three weeks. That is until late last week. After two days of rain, the free chlorine levels dropped to around 8 and the pool had that “dull” look. It was just starting to get that milky/cloudy look. So that evening, I turned the system back on and ran it for an extra 4-1/2 hours with the SWCG at 100%. The next day, after running for 10 hours at 100%, the free chlorine levels were 7.5 ppm and the pool was more milky/cloudy. So I decided to once again, throw in the towel and start the SLAM process.

Here’s some useful information and data:

I use a Taylor K-2006C test kit.

Levels (right before SLAM):
FC 7.5
pH 7.5
TA 75
CH 430
CYA 55 (* This is slightly lower than normal. I typically try and hold at 70)
Salt 4000
Temp 86ºF

* I know my stabilizer level is a bit low, 55. But considering the chlorine levels that I’m holding, is there any possibility this is the reason why my chlorine levels started dropping and the water started turning milky/cloudy? Also, as a side note, it seems like I have to add stabilizer more frequently than I would think. How is stabilizer depleted from the pool? I have not emptied any water out of the pool so far this season. I have added water a couple times do to evaporation and it has rained a couple times. Here’s some CYA data from this season:

3/17 CYA 55 (added 1 lb stabilizer)
3/21 CYA 70
3/23 Added a few inches of water to pool
3/26 Water started looking milky/cloudy (maybe the CYA dropped from adding water?)
3/27 Started SLAM
3/30 SLAM complete
4/1 CYA 60 (added 1 lb stabilizer)
4/5 light rain
4/6 Added a few inches of water to pool
4/13 CYA 60 (added 1 lb stabilizer)
4/16 Rained an inch or so in the last two days. Water starting to look milky/cloudy
4/17 CYA 55
4/17 Started SLAM
4/23 SLAM complete

Even with my higher chlorine levels, is there a correlation between my CYA dropping below 60 and my pool crashing? Along these same lines, should I be holding my CYA closer to 80 rather than 70?

Is there any correlation between the pool water temperatures in the 80’s and the pool crashing? I would think the higher the water temps, the more conducive the environment is for algae growth.

Additional Pool Information:
15,000 Gallon
Plaster with Quartz*
Salt Water
Cartridge Filter
Heat Pump
Polaris 360 Cleaner

* Note, the plaster is starting wear down and releasing the quartz, which is subsequently picked up by the pool cleaner. We have some areas in the pool that are discolored (see pic). Is there any chance that algae is growing in the small holes that are created by the quartz coming loose?



Along these same lines, I typically try and brush the pool at least twice a week during normal times and once or twice a day during the SLAM process.

I just finished the SLAM process. It took six days, but last night’s OCLT was 0.4 and the CC was < 0.2. Here is a pic from the start of the SLAM compared to a day or two from the end (I forgot to take a picture at the end.) Hopefully you can see the slightly cloudy/milky water that I'm fighting.



How often do others SLAM their pools? Every 2 to 3 weeks seems very frequent to me. I know every pool and situation is different. I am just trying to figure out how far we are from normal.

Typically my CC is close to 0. When doing the CC test, the color just every so slightly goes from clear towards pink, but it is almost undetectable. One drop and the test goes back to clear. Therefore, I would assume that means the CC is less than 0.2. Is this an accurate assumption?

I know this is a lot of information, but ultimately, I am trying to figure out why my chlorine keeps crashing and my pool turns cloudy. Any help or suggestions would be greatly appreciated. Please help me keep my wife from hiring a pool guy!

 

[Texas Splash]

Welcome to TFP! Well, let me try and re-cap a few of your concerns:
- Owners don't typically SLAM every few weeks. It's not (hopefully) a regular routine. I think my first & last SLAM was 2014 when I joined TFP.
- Some of the issues discussed like nitrates, rain, etc don't apply to this situation. Algae starts and sustains itself because at some point there was an imbalance of FC to CYA.
- CYA is expected to naturally drop slightly each month (about 5 ppm or so). Other than that, it disappears from a water exchange, splashout (kids splashing) or a water leak.
- The fact your CYA was a little under the minimum 70 doesn't seem significant in and of itself, but if the FC didn't receive the protection it needed during a day or two, then the potential for algae could have returned.
- Your test numbers look fairly solid overall, but something must be off. Either a testing variance, gap in testing, or perhaps there is some algae hiding that has yet to be discovered.
- I see you have a light. Have you ever removed it (power off) and inspected in that niche? It's a prime location for algae.

Cloudy is a precursor for algae. But you might consider running one more Overnight Chlorine Loss Test (SWG off) to see if there is any excessive FC usage overnight. In the meantime for today, I would use a little regular bleach to keep the FC elevated to about 10 or so until it gets dark, then take your your first OCLT reading. Then see how it looks again in the morning.

 

[Casey]

When you are SLAM'ING the pool, are you using liquid chlorine or are you boosting your SWG? I kept seeing you mention that you're turning it up to 100% but dont mention adding liquid chlorine.

 

[jecomer]

When you are SLAM'ING the pool, are you using liquid chlorine or are you boosting your SWG? I kept seeing you mention that you're turning it up to 100% but dont mention adding liquid chlorine.

Casey, good question. Yes, I'm using liquid chlorine from our local pool store. This past SLAM, I used about 7.5 gallons over 6-7 days.

 

[jecomer]

Welcome to TFP! Well, let me try and re-cap a few of your concerns:
- Owners don't typically SLAM every few weeks. It's not (hopefully) a regular routine. I think my first & last SLAM was 2014 when I joined TFP.
- Some of the issues discussed like nitrates, rain, etc don't apply to this situation. Algae starts and sustains itself because at some point there was an imbalance of FC to CYA.
- CYA is expected to naturally drop slightly each month (about 5 ppm or so). Other than that, it disappears from a water exchange, splashout (kids splashing) or a water leak.
- The fact your CYA was a little under the minimum 70 doesn't seem significant in and of itself, but if the FC didn't receive the protection it needed during a day or two, then the potential for algae could have returned.
- Your test numbers look fairly solid overall, but something must be off. Either a testing variance, gap in testing, or perhaps there is some algae hiding that has yet to be discovered.
- I see you have a light. Have you ever removed it (power off) and inspected in that niche? It's a prime location for algae.

Cloudy is a precursor for algae. But you might consider running one more Overnight Chlorine Loss Test (SWG off) to see if there is any excessive FC usage overnight. In the meantime for today, I would use a little regular bleach to keep the FC elevated to about 10 or so until it gets dark, then take your your first OCLT reading. Then see how it looks again in the morning.

Thanks so much for the reply and information.

I did remove the light, this time, and cleaned out the housing. For full disclosure, when I brushed out the housing, quite a bit of white particulates came out in a milky cloud. I'm assuming this was algae. So I had pretty much decided, I need to clean out the housing on a regular basis. I know every situation and pool is different but do you have a suggestion on frequency? I was thinking monthly.

As for the OCLT, the last one I did was at the end of my last SLAM which ended Wednesday night into Thursday morning. Just so I'm clear (no pun intended), are you suggesting doing another OCLT? As of this afternoon, my FC was at 17. It is slowly coming down from the SLAM.

Thanks again!

 

[Texas Splash]

I know every situation and pool is different but do you have a suggestion on frequency? I was thinking monthly.

Monthly is probably a bit excessive, but at least once each season. Folks typically take the light out and set it on the decking so that the chlorinated water can enter the niche freely for a day or two. Your call on the OCLT. If you want to monitor the water over the weekend, that's fine. I think you have a very good understand of the processes and tools at your disposal. Maybe catching that niche today will help.

 

[jecomer]

Welcome to TFP! Well, let me try and re-cap a few of your concerns:
- Owners don't typically SLAM every few weeks. It's not (hopefully) a regular routine. I think my first & last SLAM was 2014 when I joined TFP.
- Some of the issues discussed like nitrates, rain, etc don't apply to this situation. Algae starts and sustains itself because at some point there was an imbalance of FC to CYA.
- CYA is expected to naturally drop slightly each month (about 5 ppm or so). Other than that, it disappears from a water exchange, splashout (kids splashing) or a water leak.
- The fact your CYA was a little under the minimum 70 doesn't seem significant in and of itself, but if the FC didn't receive the protection it needed during a day or two, then the potential for algae could have returned.
- Your test numbers look fairly solid overall, but something must be off. Either a testing variance, gap in testing, or perhaps there is some algae hiding that has yet to be discovered.
- I see you have a light. Have you ever removed it (power off) and inspected in that niche? It's a prime location for algae.

Cloudy is a precursor for algae. But you might consider running one more Overnight Chlorine Loss Test (SWG off) to see if there is any excessive FC usage overnight. In the meantime for today, I would use a little regular bleach to keep the FC elevated to about 10 or so until it gets dark, then take your your first OCLT reading. Then see how it looks again in the morning.

PLEASE HELP!!!

My chlorine has crashed again. I am literally at my wits end. I feel like I know what I'm doing, but no matter how hard I try, I can not keep my chlorine from crashing. SLAMing my pool every 2 to 3 weeks during pool season is obviously not realistic. There has to be an underlying reason. But I can not figure out what it is. That being said, let me bring you up to date since I last posted. I have more data between 4/23 and today, but here is the most relevant:

4/23 - SLAM complete with OCLT of 0.4, CC < 0.2 and water crystal clear
5/1 (about a week later) - per your suggestion, I did another OCLT with results 0.0
5/3 - added several inches of water
5/9 at 1800 - FC 12.5, CC 0.0, pH 7.8 and CYA 75 (* I actually thought to myself that everything looked great)
5/10 - Rained for less than 30 minutes in the morning. Added several inches of water in the evening.
5/11 at 2130 - FC had dropped to 5.5 (from 12.5 on 5/9) and water was starting to look cloudy. I added 1 gallon of liquid chlorine to raise the chlorine levels and I did an OCLT. Unfortunately, the results were not valid because I forgot to turn off the SWCG and it ran for approximately 1-1/2 hours prior to my early morning test. With that being said, the chlorine drop was still slightly more than 1.0. With the chlorine drop that would have been greater than 1.0 and the fact that the pool was even more cloudy, I would consider this an OCLT failure.

To summarize, I am starting another SLAM today. It has been only been 20 days since our last SLAM was complete. Up until a day or two ago, everything looked great and it appeared our pool was stable. The only thing I can think of that started the downward slide was the rain and/or the refilling two days ago. Is there any chance organics are being introduced to the pool as the rain goes through the pool enclosure screen? FYI, we pressure wash the pool enclosure and screen once or twice a year. Is there any chance that refilling the pool caused the chlorine to crash? By my best estimates, I added approximately 1200-1500 gallons (15,000 gallon pool). I can't imagine it is my city water, because then I would assume all my neighbors would be having issues?

At this point, I am grasping at straws. I am open to any and all suggestions or ideas. I do not know where else to turn. I do not trust any advice from our local pool stores and I'm not sure a pool service company will be able to anything more than what I am already doing. Where are the organics/algae hiding? Why is the pool turning cloudy and the chlorine crashes? Any help would be greatly appreciated.

Thanks so much for all your help!

 

[Texas Splash]

While the rain itself should not be a huge factors in your recurring algae issue, the enclosure retaining dirt and debris could. However you seem to be cleaning that frequently enough, so I'm not so sure that's it either. Last SLAM you removed the light which revealed some hidden treasures, but that should be good now as well. What about a main drain? Did we ever discuss that? You don't have hollow steps or anything like that right?

 

[wilkj1]

1 thought any way the swg could be stopping or not working at all ?

 

[jecomer]

While the rain itself should not be a huge factors in your recurring algae issue, the enclosure retaining dirt and debris could. However you seem to be cleaning that frequently enough, so I'm not so sure that's it either. Last SLAM you removed the light which revealed some hidden treasures, but that should be good now as well. What about a main drain? Did we ever discuss that? You don't have hollow steps or anything like that right?

Thanks for the quick reply. Yes, I did remove the pool light during the last SLAM. It was prior to your suggestion, so it was probably only out of the enclosure for a couple of hours. I am planning on removing it again today and checking/cleaning the enclosure again. Just to make sure, I will leave the light on the pool deck for a couple days during the SLAM.

We have one set of solid steps and a solid bench in the deep end. Both are plastered into the pool. Both are curved, like a lot of my pool, so when brushing, I try and take my time to get all the surfaces.

We have not discussed the main drain. I have one at the bottom of the deep end. From what I can tell, it is plumbed to the bottom of my skimmer. Two years ago, when I got fed up and drained the pool, I took the cover off the drain and cleaned everything I could get to. Do you have any advice or suggestions when it comes to the main drain?

Speaking of the skimmer, when I SLAM the pool, is there any advantage (or disadvantage) to adding some of the chlorine right into the skimmer? My thought was that sending the hyper chlorinated water through there might help attack any hidden algae in the pipes. I know that’s a long shot, I would think that because of the fast flowing water, the pipes would be the last place algae would grow, but again, I’ve run out of ideas.

Thanks again for your help!

 

[Texas Splash]

I would remove that drain cover and inspect again. Algae is known to hide under those. As for the skimmer, it's best to never add chemicals directly to the skimmer. They become too strong and don't have enough time to dilute before making it to the equipment pad.

 

[jecomer]

1 thought any way the swg could be stopping or not working at all ?

Thanks for the reply! I’ve thought about that and I try and keep an eye on the control unit to make sure it is on and the generator to make sure it is generating bubbles. I keep an eye on scaling and have cleaned the unit a couple of times the past few years to remove buildup. I have also tested the unit a couple of times over the past few years to make sure it is working. Each time it passes with flying colors. Maybe, I’ll check it during the SLAM, just to rule it out. Let me know if you think of anything else. Thanks so much!

 

[jecomer]

I would remove that drain cover and inspect again. Algae is known to hide under those. As for the skimmer, it's best to never add chemicals directly to the skimmer. They become too strong and don't have enough time to dilute before making it to the equipment pad.

That’s what I thought and why I have never added chlorine to the skimmer in the past.
Any tips or tricks on how to work in the deep end to remove the drain cover without scuba equipment? I can hold my breathe but I tend to float up to fast. Unfortunately, I do not have a scuba weight belt.

 

[Texas Splash]

Unfortunately, I do not have a scuba weight belt.

I have seen others use a cinder block by gently laying it on the bottom. I was just enough weight hold onto to while on the bottom. Of course it took multiple dives to get the screws removed, or for as long as they could hold heir breath.

 

[jecomer]

While the rain itself should not be a huge factors in your recurring algae issue, the enclosure retaining dirt and debris could. However you seem to be cleaning that frequently enough, so I'm not so sure that's it either. Last SLAM you removed the light which revealed some hidden treasures, but that should be good now as well. What about a main drain? Did we ever discuss that? You don't have hollow steps or anything like that right?

So just an update...

I took the pool light out and as we expected there was no sign of any organics or algae. That being said, I cleaned out the enclosure again and left the light on the pool deck.

I removed the cover from the main drain and even though there was not a lot of evidence of organics or algae, there was some brownish substance on the drain and the cover. I cleaned both as best I could and I've attached before and after photos. Do you think this is algae? Also, is the discoloration normal? I don't know if you can see it in the before photo of the drain, but there was a rusted screw or some other piece of metal in the bottom of the drain. I scraped it out and cleaned as much as possible. Are there any adverse effects of this or any other rusting metal in a pool?

Lastly, I started the SLAM late afternoon yesterday and by late evening the pool was looking significantly clearer. Because it had only been a few hours, I did not perform an OCLT. I will probably do an OCLT tonight. I guess it is a waiting game at this point. Based on what I found, or didn't find, I am not sure I've found the culprit and I'm not confident the pool will remain stable after the SLAM. I've got my fingers crossed. Please let me know if you have any other suggestions. Again, I appreciate all your help!

Drain Before:


Drain After:


Cover Before:


Cover After:


Brown Substance:

 

[Texas Splash]

Nice work! It definitely looked like organic/algae staining in that drain. Glad you opened it up. Under the cover it looked almost more like an oxidation-type reaction. Hard to tell, but you certain;y got that as well. As for the discoloration on the cloth, it looks like it could be rust residue, but I couldn't imagine how unless you have iron in your water from somewhere. You're not on a a well are you?

 

[aeh0603]

Isn't recurring algae despite passing SLAMs a sign that it could be mustard algae?

It might be worth bringing your FC up to the mustard slam level for 24hrs after you pass your current SLAM just in case. Yes it would use extra FC that may or may not help, but I figure at this point it couldn't hurt in the event that the recurrence is because you have some sort of FC resistant strain of algae that the regular SLAM is not fully eradicating. After the 24 hrs, you may also want to keep your FC above the mustard minimum for a while.

To me it makes the most sense that if there is nowhere else in your pool that algae could be hiding and between SLAMs you have kept FC above minimum for your CYA, then the most logical conclusion is that the SLAM did not kill everything and what little algae was left was able to fight it's way back. I can't guarantee anything, but this is one possible explanation for the recurrence every few weeks.

 

[jecomer]

Nice work! It definitely looked like organic/algae staining in that drain. Glad you opened it up. Under the cover it looked almost more like an oxidation-type reaction. Hard to tell, but you certain;y got that as well. As for the discoloration on the cloth, it looks like it could be rust residue, but I couldn't imagine how unless you have iron in your water from somewhere. You're not on a a well are you?

Thanks! No, we are not on well water.

 

[jecomer]

Isn't recurring algae despite passing SLAMs a sign that it could be mustard algae?

It might be worth bringing your FC up to the mustard slam level for 24hrs after you pass your current SLAM just in case. Yes it would use extra FC that may or may not help, but I figure at this point it couldn't hurt in the event that the recurrence is because you have some sort of FC resistant strain of algae that the regular SLAM is not fully eradicating. After the 24 hrs, you may also want to keep your FC above the mustard minimum for a while.

To me it makes the most sense that if there is nowhere else in your pool that algae could be hiding and between SLAMs you have kept FC above minimum for your CYA, then the most logical conclusion is that the SLAM did not kill everything and what little algae was left was able to fight it's way back. I can't guarantee anything, but this is one possible explanation for the recurrence every few weeks.

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?

 

[Texas Splash]

But if there was some mustard algae or some other stubborn algae remaining after a SLAM, wouldn’t that cause the OCLT to fail?

Not always the case really. Residual algae can be so tiny it hardly effect testing, but can return quickly. Yet another reason why we have 3 passing SLAM criteria.