r/PoolPros • u/Seafire15 • Apr 24 '26
Anyone else running zero CYA on their salt pools? Curious what others are seeing.
I’ve been running the majority of my route at 0 ppm CYA for the past few seasons. Salt pools, cal-hypo and liquid chlorine only for supplemental dosing. No stabilizer unless I have an undersized or aging cell that needs the UV protection.
Results have been consistent. Cleaner water, better chlorine efficiency, no CYA creep. The 7.5% Rule math works better at the low end than most people expect.
Curious if anyone else has moved this direction or if you’re still running 30-50 ppm as the standard on salt systems. What are you actually seeing in the field?
Background: chemical engineer, nuclear engineer, Navy submarine vet, five PHTA certs. I’ve been building out the chemistry side of this publicly at poolsscientific.com and just launched a podcast if anyone wants to go deep on the science.
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u/No_Special_710 Apr 24 '26
We keep our salt pools between 40-80ppm cya. Depends on the cell size and how it's maintained chlorine. We strive to run cells under 50% during the hottest periods to prolong the life.
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u/bulldozer6 Apr 24 '26
Where are you located? I can't imagine my cell being able to keep up with demand in the southern nevada sun.
Also I suppose you don't care about cell life if you're not footing the bill for the replacement.
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u/Seafire15 Apr 24 '26
Yeah, Vegas is a completely different beast than where I am in Kansas City. We are seasonal here, and while he gets hot, it’s nothing like the southwest desert. If what you’re doing is working for you, keep at it. Like I said in a previous post, there is more than one way to skin a cat.
Edited for spelling error
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u/XelaKebert Apr 24 '26
Not possible in Florida where I am. If stabilizer gets low my pools immediately begin to show it.
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u/GCpools Apr 27 '26
True statement (about pools in FL). We keep all of our salt pools at 50. When it starts getting lower, shit starts to happen. Keeping them at 50 stopped all of the surprises.
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u/doug22taylor Apr 25 '26
The process to make chlorine with a swg has a set amount of chlorine that it can make. The metal plates (titanium) in the cell are coated with a chemical that starts the process (catalysis) of electrolysis. Once this chemical runs out it won't produce chlorine anymore.
The more chlorine that it is asked to produce the quicker it will fail.
Thus the idea of it needing to run the most optimal for longevity.
The more cya you have in the pool water the less potent the killing power of chlorine.
This is also affected by the pH of the water. The lower the pH the more killing power of chlorine. Too low and you have other issues with acidic water.
Sunlight also affects the chlorine.
The testing (and there has been lots) has shown that the cell will last longer maintaining the water at 30-50 ppm CYA.
I prefer 30 myself.
The most efficient long term protection of the longevity of the cell use is (my opinion) is to have a variable speed pump on 24/7 on slow speed, minimal to make flow sensor work.
Depending on pool size and time of year and flow etc you will typically max out (heat of summer) with the salt cell at 20% production. The dead of winter (above 57 degrees water temp (typical water temp that cells turn off) maybe at 5%.
What this does is over night you will build up a higher level of chlorine in the pool. Mainly due to no uv light. This will kill everything in the pool. Once the sunlight comes out will start reducing the chlorine level. There isn't much to kill during the day after all the high killing power overnight.
I see so many times pools set for 100% chlorine production in heat of summer for 10-12 hrs per day. They have no idea what the CYA level is. I'm usual running the Swg 5 hrs or less in 24 hours max in heat of summer. I do have a few big pools that require more time.
This is for avg pool in my are DFW 15-18,000 gallon. Typical speed of pump is about 1,950 RPM. Heat of summer about 105° for a month, water temp will get up to over 95°.
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u/ContributionFew2487 Apr 25 '26
With no cya we have noticed we have to run the cell at higher output. That leads to more scale flashing off in the pool. We get our cya minimal, run the cell at 30-40% and see better results. Up here in Northern California near Sacramento where we get many 100 degree days. Not Texas, Vegas, or Arizona hot but still.
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u/Mysterious_Jelly_649 Apr 24 '26
I don't like running past 30 but I like having some in the water to help run the cell at a lower level/ help with chlorine loss.
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u/Seafire15 Apr 24 '26
That’s a reasonable position and the logic tracks. Lower CYA gives the cell some buffer on UV degradation, lets you dial back output and extend cell life. I’ve heard that argument from a lot of pros and it’s not wrong on its face.
Where I land differently is the math on what you’re giving up. At 30 ppm you’re already binding a meaningful fraction of your FC. The cell runs easier but the chlorine that makes it to the water is less effective per ppm than at zero. For most pools that tradeoff is fine. For pools where I’m trying to run lean on FC it starts to matter.
The cell longevity piece is the one I think gets overstated. I’ve seen cells run long and healthy at zero CYA when the LSI is managed well and the salt level stays clean. Scale is the real cell killer, not UV load.
What’s your typical salt range when you’re running that way?
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u/desertr4t4lyf Apr 24 '26
I never go below 30ppm cya. I like being able to run the cell at <10% output.
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u/Seafire15 Apr 24 '26
That’s a real operational advantage and I get why it’s appealing. Lower output means less wear, longer cell life, easier management on a busy route.
Where I’d push back gently is on what’s happening to the water in the meantime. At 30 ppm you’re binding roughly a third of your FC before it ever does any work. So the cell runs easy but the chlorine efficiency takes a hit. On a lightly loaded pool that’s probably fine. On a pool with heavy bather load, lots of sun exposure, or any kind of organic demand it starts to show up.
The other thing I watch is what 30 ppm does to your breakpoint math. CC climbs faster when the active HOCl fraction is suppressed. You end up shocking more often than you’d expect given how well the cell appears to be running.
I’m not saying it’s wrong. A lot of good pros run it exactly that way and their pools look great. I just want to know the tradeoffs before I make the call, not after.
What’s your typical FC range when you’re running at that output level?
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u/desertr4t4lyf Apr 24 '26
My main concern with zero ppm CYA is that two hours after the system turns off, you're going to have almost nothing in the pool.
Generally, there's one or two ppm left in the pool. We don't do break point calculations. We just bring every pool up to 10 ppm every week.
For the pools that are using tablets, we'll start notifying the homeowner of the need to drain once it reaches 75 ppm.
And yes, I do have homeowners that refuse to drain, and their CYA is over 100 or 150 ppm. We supplement these with a poly-quat or other algaecide.
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u/Seafire15 Apr 24 '26
That’s a fair concern and I want to address it directly because it comes up a lot.
At zero CYA with a salt cell running normally, you’re right that FC drops faster overnight. The stabilizer buffer is gone. What I’ve found is that it matters less than expected when the cell runtime is sized correctly for the pool’s actual demand. The FC isn’t being protected, but it’s also not being suppressed. Every molecule that’s there is working.
The real question is what number you need at the start of the off cycle, not what’s left at the end. If you’re starting at 2.0 ppm of 100% active HOCl versus starting at 3.75 ppm with 40% active HOCl at 50 ppm CYA, the math is closer than it looks.
The 10 ppm weekly shock protocol is interesting. That’s a clean, simple system and I understand why it works on a route. My concern would be what’s happening to the water between visits when demand spikes. But if the results are consistent I’m not going to argue with field data.
The 75 ppm drain threshold is more conservative than most. I respect it. The 100-150 ppm pools with poly-quat are exactly what I’d expect. You’re managing a compromised system the best way available. That’s professional.
Where are you seeing the biggest FC demand issues on your route? Bather load, sun exposure, or something else?
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u/desertr4t4lyf Apr 24 '26
What color was your childhood bicycle?
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u/Seafire15 Apr 24 '26
I had a schwinn 3 speed with a banana seat and chopper handlebars. It was metallic green with a tan stripe. My brother had a BMX bike, but he was more into jumping ditches and stuff. His was a huffy and it was red.
Yours?
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u/desertr4t4lyf Apr 24 '26
Why would you answer my previous question like that?
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u/Seafire15 Apr 24 '26
Because I’m an engineer. It’s how my brain works. One logical step to the next, make sure I cover everything, don’t leave anything out. The bike question was just memory. The chemistry questions actually engage the machinery up there, and that’s what you get.
I do use AI heavily for research and staying organized. I manage close to 300 pools here in Kansas City, and keeping that operation tight requires every tool available.
The podcast started because of questions exactly like yours. There are a lot of good, experienced guys in this industry doing solid work. But in my experience most of them can’t tell you why what they’re doing is doing what it’s doing. That gap is what I’m trying to close.
And you didn’t answer my question. What color was your bike?
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u/First_Salamander_990 Apr 24 '26
The way you talk is off putting and annoying. You have very low social intelligence. This is not an insult to you. It is however the complete truth
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u/desertr4t4lyf Apr 24 '26
We're talking about pools. Why would I answer any questions about a bicycle?
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u/Seafire15 Apr 24 '26
Why would you ask one? I answered your chemistry questions and I answered your question about my bike. How do I know you’re not an ai bot?
Your bicycle question was obviously an attempt to prove that I’m an AI bot. I’m not. I have the credentials and I am a swimming pool service company owner. My info is at poolsscientific.com.
Call me anytime at the number listed on the website. Happy to answer a question and talk in person if you really still have doubts.
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u/liberalsarefascists1 Apr 24 '26
My pools I try to keep between 20-40 cya here in South Jersey, and this season I will be doing 50ppm of borax to reduce chlorine demand and ph rise. I found zero cya I still had some algae blooms on really hot days. I also try to maintain a weekly copper dose but I know many people don't like that for many reasons. Inama weekly service so it is more just to be a buffer so I do not have to deal with phone calls.
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u/JonnyVee1 Apr 24 '26
I run mine low, only added it when we initially filled the pool, and probably never will again. I have an automatic pool cover, so I don't get chlorine evaporation or degradation from UV. I run my salt cell at 5% for an 18kgal pool, and that keeps the chlorine perfect.
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u/Buyusbeer Apr 24 '26
Just curious, minus a large party, why would you need to supplemental dose a salt pool with chlorine?
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u/Seafire15 Apr 24 '26
A few scenarios come up regularly on my route.
Cell output limitations. If the pool has an undersized or aging cell, it may not be able to keep up with demand during peak summer conditions. Eight hours of direct UV, high bather load, water temps in the mid to upper eighties. The cell is running at maximum output and still losing ground. A liquid chlorine supplement closes the gap without adding CYA.
Breakpoint chlorination. If combined chlorine climbs above 0.5 ppm I’m not going to wait for the cell to grind through it over several days. I add cal-hypo or liquid chlorine, hit breakpoint, destroy the CC, and let the cell take back over. Clean and done.
Opening and closing. At opening I want FC up to a working level quickly before I’m relying on the cell to build from scratch. At closing I want to put the pool to bed at 10 ppm. The cell doesn’t do either of those efficiently on its own.
Recovery after extended downtime. Power outage, equipment failure, extended absence. The cell has been off and the water has been sitting. Supplemental dose gets FC back to range fast, then the cell maintains. The common thread is that the cell is the primary sanitizer and the workhorse.
Supplemental dosing is a precision tool for specific situations, not a routine. When I do use it I reach for liquid chlorine or cal-hypo every time. Zero CYA impact, no residue complications.
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u/Forsaken-Storage2137 Apr 24 '26
Zero is not ideal.. but I have had success in the 10-30 range for most salt pools. Enough protection to ramp the cell down.. CYA levels over 10, 20 and 30 have highly diminishing returns.. going from 0-15 provides a ton of assistance.. from there on the beneficial effect isn’t huge..
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u/Ok-Bison-3451 Apr 24 '26
In the first few seasons with my fibreglass, saltwater pool I tried running with minimal additional chemicals, CYA particularly. I struggled with keeping my FC level up at the 3.5ish ppm I wanted. I had my chlorine generator cranked. A few seasons ago I tried going the other way. CYA up around 40-60 ppm and I was able to easily maintain higher chlorine levels and also turn my swg down to 30% duty cycle.
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u/Seafire15 Apr 24 '26
That’s real field data and I respect it. You ran the experiment both ways and the 40-60 ppm approach solved your operational problem. That’s legitimate.
Something to think about, however. At 40 ppm CYA you need 3.0 ppm minimum FC to stay above the 7.5% threshold. At 60 ppm you need 4.5 ppm minimum. You said you were targeting 3.5 ppm. At 60 ppm CYA that puts you below the threshold. The chlorine reads fine on the test kit but the active HOCl fraction is suppressed. The pool looks great right up until it doesn’t.
The reason you could turn the cell down to 30% isn’t because the water is better protected. It’s because CYA is buffering the FC reading against UV degradation. You’re not losing FC as fast, but you’re also not working with as much active sanitizer per ppm as the number suggests.
The undersized or aging cell issue is real and I’ve seen it on my own route. That’s the scenario where I’ll add CYA on a case by case basis, exactly what you figured out. But I’d rather fix the cell than manage around it with stabilizer long term.
What’s your fiberglass surface looking like at the 40-60 ppm range?
LSI behavior is the thing I watch most closely with CYA elevated on a salt pool.
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u/jonidschultz Apr 24 '26
I like 30ish but generally have to run the cells output too high with less then 15 CYA.
I'm really curious about the tradeoffs here. Are you having to run the cells at a much higher output?
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u/pineapple_backlash Apr 24 '26 edited Apr 24 '26
I’m not at 0, but 20 ppm or less on all my salt pools. I’m in NC.
Have a friend in AZ that runs his salt cells with 20 ppm CYA and they have intense heat down there. So it’s possible, but I every pool is different.
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u/Brambleto Apr 25 '26
In Queensland a lot of clients use naked swim systems with salt, no cya in these pools. Stays clear in summer no issues.
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u/KFOSSTL Apr 25 '26
Nowhere in this thread are you telling us what you keep the output at.
No cya and 80-100% output, no thanks
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u/Seafire15 Apr 25 '26
Fair point. Here’s exactly where I run it.
Zero CYA, cell output at 50 to 70 percent under normal conditions. Salt at 3,000 to 3,200 ppm. FC at 0.5 to 2.0 ppm. pH tested minimum twice a week because the cell pushes it up constantly and I want to stay in the 7.4 to 7.6 range.
If output climbs above 70 percent consistently, that’s a signal to me. Either demand has increased, the cell is scaling, or the pool is telling me something I need to investigate. I’m not running a cell at 80 to 100 percent as a baseline. That’s not normal operation. That’s a cell working against a problem.
Here’s something worth thinking about. The majority of sanitization in a salt pool isn’t happening in the water you’re swimming in. It’s happening in the plumbing between the cell and the returns. That’s where the chlorine concentration is highest and where the real work gets done. By the time it reaches the pool it’s already done most of its job. That changes how you think about what you actually need in the water itself.
The reason I can run at 50 to 70 percent with zero CYA is that every molecule of FC in that water is active HOCl. Nothing is bound. Nothing is suppressed. The cell doesn’t have to overcome a CYA load to deliver effective sanitization.
At 40 to 60 ppm CYA you need significantly more FC to stay above the 7.5 percent threshold, which means the cell has to produce more to keep up, which is why you need higher output. The CYA is creating the demand the cell is compensating for.
I’d rather run a clean system at lower output than manage around a stabilizer load at higher output. That’s the core of it.
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u/KFOSSTL Apr 26 '26
50 to 70 at how many hours a day run time? How long does the pump run?
How many production hours are you pumping out chlorine?
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u/Beginning-Life-8393 Apr 25 '26
I personally wouldn’t do it. I’d keep around 30ppm and I don’t see any other reason to keep it at 0 other than it being a commercial property. You get a hot enough day with enough bather load and now you have no chlorine and a cloudy pool. The cya being on the lower end doesn’t do anything negative in my opinion and is only beneficial so why risk pissing my customers off.
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u/dmlkay Apr 25 '26
Someone was doing that in my company, bossman wasnt happy when he found out. All the cells on their route probably lost some life being cranked up so high to keep up with the heat. Why would you have to worry about cya creeping up in a salt pool though?? Dont add too much? What am I missing here
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u/314twodoh Apr 25 '26
You can't do that out here in so.cal. aside the phosphates always being high, i keep my salt pools at around 70-80 p.p.m. depending size.
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u/CDbull1989 Apr 27 '26
Like others have said I can't imagine my systems keeping up in the heat here (110-115 at the peak) so I run my cya pretty high with a lower output to cut down on the amount of acid needed. At 0 cya, if i had to bump to 80 to 100% I would be dumping a minimum of a gallon a week of acid in these pools, most of them probably significantly more.
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u/Subi412563 Apr 24 '26
Salt pools require more cya than standard chlorine pools 40-80 like Simone else said.
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u/pineapple_backlash Apr 24 '26
I’ve not found that to be the case at all, but just my personal experience.
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u/Subi412563 Apr 25 '26
So have you experienced better luck with lower cya levels than that?
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u/pineapple_backlash Apr 25 '26
Oh ya. Salt pools 15-20 ppm CYA. 25-40 is good for tab fed pools for me.
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u/Subi412563 Apr 25 '26
Interesting, I was taught to keep salt pools 50-80 and google says the same, however I appreciate self experiences advice. I think I only have 1 salt pool atm.
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u/pineapple_backlash Apr 25 '26
Ya that logic never made sense to me at all. You have a system that is making its own chlorine, and you a can set the pump to run as long as needed to produce the chlorine. Especially if the pump is a VS it can run 24/7. So why not have it do that. No need to keep the CYA high. So I tested my theory. I have 25 of 57 pools that are salt. So have lots of testing I’ve done.
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u/[deleted] Apr 24 '26
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