Cya, chlorine, and algae problems

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T

temily

Member
Mar 11, 2023
7
Louisiana
Pool Size
25000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Jandy Truclear / Ei
am struggling with chlorine in my salt pool!!
We got a new salt cell about 6 months ago, new filters, and everything was going great. I test my water with a Taylor kit. About 1.5 months ago I noticed the water was a bit hazy after a heavy weekend use. Shortly after the water turned green. I realized I had been neglecting the filters and there was basically no flow.
We cleaned the filters, rebalanced the chemicals but I could not get chlorine (free) to stay in the water. I hadn't tested the cya recently and when I did my test showed basically 0. I added cya per the instructions but still nothing with the chlorine. When I re-tested the cya it still tested really low so I added more (this was weird because I’d add and it would go up and then a day or so later it would be lower and back and forth like that).
I'd been adding liquid chlorine during this process and that would help for a short time, but as soon as I stopped it turned green again (about 1-2 gallons per day). I read that I'd need to really shock the pool to overcome the algae so I added 6lbs of granular shock (yes, I was super frustrated at that point). I didn’t know at the time that would increase the cya so when I re-tested the cya it was now, too high.
I drained some water and then my test was about 60 for cya. I made sure all the other chemicals were balanced but I still couldn't keep chlorine in the pool. I finally had enough so I called the pool guy out and he tested the cya and said it was 100 (my test still showed about 60) so he put this bag in the filter basket to help reduce cya. He said it would be about 1 week to reduce it but to test it every other day. 2 days later my cya test said basically 0. I got new reagent and retested today and still about 0.My pool is still green and has no free chlorine. At this point I'm at a loss and have no idea what do next. I don’t know why my CYA test and his are so different so I don’t know if it’s CYA or what? He tested the salt cell and it’s fine, no build-up, filters are clean, all chemicals are balanced, but no free chlorine (but combined is high). Do you have any advice?? Thanks!
 
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Parts of your descriptions leads me to believe you are fighting ammonia in your water.
Try this If your CYA is 0
Add sufficient liquid chlorine to achieve 10 ppm for your pool, then test your free chlorine after 30-minutes. You likely have ammonia in your water if you lost 80%+ of FC in 30 minutes, if you only have 1 - 2 ppm of FC.

If you do hold FC for 30 mins then it is not ammonia and we can discuss other options.

@Mdragger88 may have some other opinions.
 
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HermanTX said:
Parts of your descriptions leads me to believe you are fighting ammonia in your water.
Try this If your CYA is 0
Add sufficient liquid chlorine to achieve 10 ppm for your pool, then test your free chlorine after 30-minutes. You likely have ammonia in your water if you lost 80%+ of FC in 30 minutes, if you only have 1 - 2 ppm of FC.

If you do hold FC for 30 mins then it is not ammonia and we can discuss other options.

@Mdragger88 may have some other opinions.
Click to expand...
Thanks for responding! Interesting you mentioned ammonia, in all my struggles and research over the last months one of the things I'd gotten was a test kit for ammonia. I re-did that test today and it's showing at least 1ppm ammonia in the pool. I just looked that up and it says I need to SLAM my pool (this is a new term to me and I don't know exactly what it means). The directions I found are:

Here are the steps to perform and eliminate ammonia in your pool:

1). Using liquid chlorine of 12.5% chlorine, add enough chlorine to raise your FC level to 10ppm(recommended). 10 oz. of 12.5% liquid chlorine will raise FC by 1ppm in a 10,000 gallons pool. So, you need to add about 100 oz. of liquid chlorine to raise your FC by 10ppm in a 10,000 gallons pool.

2). Test your FC level in 15 minutes, if FCL falls below 5ppm, add more chlorine to raise it back to 10ppm.

3). Repeat step 2 until your FC becomes stable between 5 to 8ppm for at least 20 minutes to be sure you have killed all ammonia.

4). Leave your FC level to come down to 3ppm and balance your water chemistry starting with Cyanuric acid to avoid losing more free chlorine.

Does that sound like what you would recommend? Thanks again!!
 
Pretty much. You have poolmath, right ? Use it to dose to 10 FC and give it 30 mins

Test and redose until the FC mostly holds for 30 mins.

Once it does, get 30ppm CYA hanging in front of a return in a sock and SLAM Process

If you add the CYA before the ammonia is gone it will become more ammonia, needing even more chlorine.
 
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Newdude said:
Pretty much. You have poolmath, right ? Use it to dose to 10 FC and give it 30 mins

Test and redose until the FC mostly holds for 30 mins.

Once it does, get 30ppm CYA hanging in front of a return in a sock and SLAM Process

If you add the CYA before the ammonia is gone it will become more ammonia, needing even more chlorine.
Click to expand...
Thanks, I got the pool math but I don’t understand how to determine my SLAM level?
 
Slam target is 40% of your CYA

swcg_chart.jpg

Go to the FC tab and toggle 'SLAM' under where you enter your CYA. (Also enter your CYA) it will autopopulate as your target and then just enter your baseline to see how much chlorine gets you from A to B.

When you enter it as your target in poolmath it will likely tell you it's out of range or not recommended. It's because SLAM is not a normal level. Disregard the warning.
 
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If you have no cya your slam level is 10ppm.
Any cya 20 or below has a slam level of 10ppm.
On the overview page hit the fc card- that will take you to the fc page -
Enter your cya of 0
current fc 0 & toggle on the slam switch
It will show 10ppm target
IMG_7726.jpegIMG_7724.png
Then it will tell you how much bleach to use based on your strength
 
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Again, thanks! I started the process but not sure if it’s going right. The calculator said 2.5 gallons of chlorine to bring it to 10ppm. I added that, then tested at 30 minutes. It was 1ppm free chlorine. I added 2.5 more gallons, waited 30 minutes, 1ppm chlorine. Did that again two more times so now I’m at like 10 or so gallons of chlorine in the pool but still not seeing it move past 1ppm free chlorine. Is that normal? Thanks!
 
temily said:
Again, thanks! I started the process but not sure if it’s going right. The calculator said 2.5 gallons of chlorine to bring it to 10ppm. I added that, then tested at 30 minutes. It was 1ppm free chlorine. I added 2.5 more gallons, waited 30 minutes, 1ppm chlorine. Did that again two more times so now I’m at like 10 or so gallons of chlorine in the pool but still not seeing it move past 1ppm free chlorine. Is that normal? Thanks!
Click to expand...
You are on the right track. You need to keep adding LC. Please read

Ammonia - Further Reading

www.troublefreepool.com www.troublefreepool.com

Important part

Getting Rid of Ammonia in Pool Water​

  1. Dose the pool to SLAM level of 10 ppm
  2. Do not add any CYA until chlorine begins to hold
  3. Test chlorine every 30 minutes until chlorine begins to hold. Add chlorine as needed to get back to 10 ppm. FC will likely test close to 0 until you get to the next step
  4. You will know when the chlorine begins to hold when you begin seeing FC testing > 3 ppm after 30 minutes.
  5. When you see a significant jump in FC from the prior 30 minute test CYA can be added back into the pool. Limit the CYA to 30 ppm for the duration of the process
  6. Increase the FC target to 12 ppm and follow the steps in the SLAM Process until the criteria of “Done” are all met.
  7. Follow the SLAM Process FC test procedures. You no longer a need to test every 30 minutes at this stage.
 
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Thanks again for all the great information! I'm on day two of my SLAM process and I have a couple more questions:

1) We bought our pump filters in May/June and cleaned them about one month ago when we started having all the algae issues. This morning the gauge on top of the pump has creeped up to "dirty". I know I need good filtration during SLAM but I also know I'm supposed to run the pump 24/7. I still have decent flow in the pool (when I put my hand in front of one of the returns it feels like a strong flow). Should I turn the pump off for a couple of hours to clean the filters or just finish the SLAM and then clean them?

2) My CYA level was (and still is) basically zero. After the initial shocking to remove the ammonia I added stabilizer to my filter baskets on Friday night (probably one lb less than what I calculated I needed but I was afraid to overdo it). I read online it can take a few days for CYA to dissolve/register on a test. This morning I checked the baskets and there's just a little left but mostly it's dissolved. I tested but still got basically zero (the water is hazy in the tube but I can still see the black dot easily when it's completely filled). I think I need to add more stabilizer but some websites said it could be up to 5 days for the stabilizer to integrate I don't want to add too much too fast. Should I add more now or is there a recommended number of days to wait between additions?
 
temily said:
Should I turn the pump off for a couple of hours to clean the filters or just finish the SLAM and then clean them?
Click to expand...
The factory 'dirty/clean' thingie is probably useless. The next time you clean them, note the PSI after. When that PSI increases 25% its time to clean. This is a much better customization for your specific pool. The +10 PSI readings on the factory ones that don't account for if your PSI started at 2 or 28. That's either 5X the PSI, or 35% and a huge difference.

With good flow that means you don't technically need to clean yet, but a +25% will give you the heads up it's gonna be soon and you should probably get to it before it clogs while you're at work.
temily said:
I added stabilizer to my filter baskets
Click to expand...
2 Issues here. Below 30 is sketchy to read, so a 20 may look like 0, or it may be trapped in your filter being slowly dissolved. Sometimes it takes a week to get out of the filter, which is why we rec hanging a sock in front of a return.

Also, this is the one time that you knew for a fact it was 0 because the ammonia so you can add that extra pound you withheld. Any future tests barring more ammonia or a full water exchange will have some CYA even when they look like none.
 
temily said:
2) My CYA level was (and still is) basically zero. After the initial shocking to remove the ammonia I added stabilizer to my filter baskets on Friday night (probably one lb less than what I calculated I needed but I was afraid to overdo it). I read online it can take a few days for CYA to dissolve/register on a test. This morning I checked the baskets and there's just a little left but mostly it's dissolved. I tested but still got basically zero (the water is hazy in the tube but I can still see the black dot easily when it's completely filled). I think I need to add more stabilizer but some websites said it could be up to 5 days for the stabilizer to integrate I don't want to add too much too fast. Should I add more now or is there a recommended number of days to wait between additions?
Click to expand...
Per the ammonia guidelines - did you see that your FC loss reduce after 30 mins of addng chlorine?
  1. You will know when the chlorine begins to hold when you begin seeing FC testing > 3 ppm after 30 minutes.
  2. When you see a significant jump in FC from the prior 30 minute test CYA can be added back into the pool. Limit the CYA to 30 ppm for the duration of the process
 
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HermanTX said:
Per the ammonia guidelines - did you see that your FC loss reduce after 30 mins of addng chlorine?
  1. You will know when the chlorine begins to hold when you begin seeing FC testing > 3 ppm after 30 minutes.
  2. When you see a significant jump in FC from the prior 30 minute test CYA can be added back into the pool. Limit the CYA to 30 ppm for the duration of the process
Click to expand...
Yes, Friday night I was checking every 30 minutes and did that process for several hours until the free chlorine was holding at 30 minutes. I added the CYA after that. Thanks!
 
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Thanks again to everyone who helped!! It’s been a week and the SLAM was successful. There is no overnight chlorine loss, CC is 0, and the water is clear.

How do I transition off the SLAM? Is there a method or do I just turn the salt generator back on? When can I stop running the pump 24/7? Thanks!
 
temily said:
How do I transition off the SLAM?
Click to expand...
Let the FC drift down to target range. It might take several days this time of year. Once in range, fire up the SWG to match the recent daily loss, monitor and adjust as needed.
temily said:
When can I stop running the pump 24/7? Thanks!
Click to expand...
Now.

temily said:
SLAM was successful. There is no overnight chlorine loss, CC is 0, and the water is clear.
Click to expand...
:salut:
 
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It’s getting to be the end of the swimming season (low uv) but if you don’t plan to close your pool anytime soon you may want to aim for 50ppm cya now to help your swcg maintain fc more easily & follow the appropriate
FC/CYA Levels 🎯 levels.
In the spring/summer most in your area find they need around 70ppm cya.
 
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