Is CYA Absolutely Necessary???

[kchinger]

A 60% setting on your size pool and SWG, in IA, this time of year, seems extremely high.

My RJ60 (granted, makes more chlorine than your IC40, but my pool is also 50% larger) basically never gets above 30% for 6 hours, even in the summer, and I have a solar cover, not a dark cover.

Right now I'm at 15% (or 10%, I can't remember, call it 15%) for 6 hours, which is 90 %-hours (a unit which is useful in these discussion, but not common, I think it should be).

If you're at 60% for 24 hours, you're at 1440 %-hours right now, in early June. You're running your SWG as hard in 2 days as I am in an entire month.

 

[dunginhawk]

I just wanna know things
So with that CYA chart (btw ive read it 100 times prior to this discussion). Why does it recommend such a high number 70/80 for SWG pools? It seems as though most SWG vendors (again i know they are vendors) say they want to see FC in the 1-2 range.

What would be the downside of running CYA at like 30-40 in a pool like mine (or others). ??

Again, this is hypathetical... But assuming my pool is operating with No CYA at a pretty solid spot. (Which again, I am not saying its right). Wouldnt adding even half the recommended CYA be a pretty dang good spot to be? I know there is some math behind the numbers (its not clearly spelled out in the chart, nor does it need to be). Was just curious if I ran my FC at 1-2 with CYA of 30/40 What im missing out on?
The obvious potential first answer would be that I am dangerously close to zero, and if I get there, Georges worlds collide... other than that?

 

[Pool_Medic]

I have done a lot of experimenting with my SWCGs over the years. 22,000 gallon pool. Run with 0 CYA and I need to run my pump 24/7 with SWCG set at 60%

80 ppm CYA, I can run my pump 10 hours at 40%.

Both kept my chlorine around 5, I’m not a huge tester, so I don’t test often.

Your cell has a limited amount of chlorine it can produce. It’s the same as a tank of gas, go 75 mph on a highway or go 45 on a highway, same distances travelled. Zero CYA I figure my cell will last 3-5 years. 80 CYA it should last 5-7. Plus the bonus of my chlorine being buffered by the CYA means it’s less harsh and less prone to UV breakdown.

60% for 8 hours or 20% for 24 hours are about the same. No way 20% in a pool with 0 CYA would maintain enough chlorine to keep a busy pool clear.

 

[Leebo]

As it's clear the OP is wanting to learn, I'll also toss in this part...........................

Keep in mind that with zero CYA maintaining a very low pH is also vital. While pH doesn't play a huge part in the strength of FC when there's CYA in the water it does play a large part when CYA is absent. Because of this you may find yourself using more acid to keep pH down.

 

[dunginhawk]

A 60% setting on your size pool and SWG, in IA, this time of year, seems extremely high.

My RJ60 (granted, makes more chlorine than your IC40, but my pool is also 50% larger) basically never gets above 30% for 6 hours, even in the summer, and I have a solar cover, not a dark cover.

Right now I'm at 15% (or 10%, I can't remember, call it 15%) for 6 hours, which is 90 %-hours (a unit which is useful in these discussion, but not common, I think it should be).

If you're at 60% for 24 hours, you're at 1440 %-hours right now, in early June. You're running your SWG as hard in 2 days as I am in an entire month.

So this is with the cover OFF.. which means all day long my FC is being sent to the ether... Once the cover goes on I fully feel I should be able to reduce it to 20% easily...

 

[duraleigh]

I really think dunginhawk has cleverly put thousands of us defending a method we know to be bulletproof.......and has done so by promoting his techniques that we all know will make pool water management more difficult.

Shouldn't it be the other way around? Shouldn't dunginhawk be the one defending his process? Shouldn't dunginhawk be "proving" to us that his methods will work and work well and inexpensively.

dunginhawk, I propose you give your methods and ideas a year to put into practice. Report back in June of 2020 and let us know how it is going......we may all have something to learn.

 

[dunginhawk]

hahahaha Dave... no, that wasnt at all my intention... Im still learning myself... I PLAN to use CYA but like ive said a few times I just like to push the envelope a bit... Someone had to come up with the thought of using CYA in the first place... Pool maintenance has changed over the years... Nothing without someone pushing for something interesting? Borax anyone?
Im not in any way saying im trying to change the way things work but I am trying to understand the whys Thats just my inquisitive nature.

Maybe I should give it a go this summer.. report back how big of a failure it was haha

 

[duraleigh]

Maybe I should give it a go this summer.. report back how big of a failure it was haha

of course you should! No one else is going to and we all might learn something....perhaps there will be no failure......only success.

Show us by example you have a better idea but don't argue that you have without backing it up with some real time, meaningful data.

At this point this is just arguing for the sake of the argument.......This forum doesn't engage in that. We have developed a method that works virtually bulletproof and that's what we teach.

 

[dunginhawk]

If you go back and read through every post I made I never argued at all... I was simply inquiring if it was possible. How does one know whats possible until the status quo is challenged. Like I said, someone at some point had to figure out that if you charge a coated plate electrically it can convert salt to chlorine gas... Im not saying this is going to work, or that its even feasible but I also dont think its disrespectful to the forum to challenge thought. Thats the point if you ask me. We should all be pushing each other to offer the best solutions. This is a fluid (no pun intended) industry at best. TFP exists because people were sick of the way pool stores engaged in sales tactics etc. No sane person can argue TFP isnt a better way than cranking in algaesides and clarifiers and all sorts of nasty expensive Crud in to our pools.
TFP works.
I dont want to get a label on here of someone whos challenging the work thats been done.. I just like to know why... Im not a sheep... Thats all If i decide to do the test and see what happens, ill certainly keep you posted.

 

[Flying Tivo]

Challenges are very welcome, but this forum try's to attend to new pool owners and guide them with a solid base of information. I think there is another forum spot to post this type of challenge its called the Deep End. We would't want new pool owner to get the idea that a pool can be managed without CYA.

 

[LFrankow]

I can run my SWG with a CYA of 50, set @ 60% for 9 hours, or
I can run my SWG with a CYA of 70, set @ 30% for 9 hours.
60% = 40 minutes per hour, 30% = 20 minutes per hour
SWG's have giant transformers inside them, the longer a transformer runs the warmer it gets, heat lessens the lifespan of a transformer.

 

[dunginhawk]

Challenges are very welcome, but this forum try's to attend to new pool owners and guide them with a solid base of information. I think there is another forum spot to post this type of challenge its called the Deep End. We would't want new pool owner to get the idea that a pool can be managed without CYA.

I certainly dont mind if a mod wants to move this to the deep end... totally cool with that.

Funny that right as my cover is going on today YAY... I walk talking to the PB assistant (right hand man) and right or wrong they never do CYA in any of their pools.
Lets call it wrong
So this particular PB is amazing at building pools but I would say less than enthusiastic about maintaining the chemistry once its done.
In fact all he does is make sure PH is reasonable and TA is reasonable, and the SWG is working and hes out.
Never tests Calcium, Salinity (cell says its ok, its ok).
I consider that fairly insane, as any TFP person would.
However, he has hundreds of pools hes installed and opens/closed every year. I imagine if he had massive issues with how hes doing things, it would have showed up by now.
I would never be so carefless with not managing it more closely but its crazy to me he does.

So now my balancing act begins... First thing im going to do is get my salinity where it wants to be for my SWG (3400 i think)
Then ill work on PH and TA
Also considering bringing Hardness up from 100-250. 100 seems just too low for a FG pool.
At least now I wont be blowing all my hard earned FC out in to the atmosphere

 

[Flying Tivo]

Dont go adding all the salt at one time. Test your salt levels first and Aim for 2800ppm and slowly go up. My IC likes anything between . 2800-3000, any higher and you can start to taste the salt. If the light is green is good to go.

 

[santacruzpool]

I have a covered pool and I have a little bit of experience with trying to run a lower CYA and can share my results. However, I have never tried zero CYA - I think the FC would be way to harsh and it would start eating swimsuits and even degrading my expensive cover. Remembering back to my prior post, a FC of 4 with the CYA at 30 the swimmer, and cover, is only exposed to .112 of active chlorine - with a FC of 1 and the CYA at zero it is 10 times more.

I have run my CYA down from a high of 50 to as low as 20 (the Taylor test fails to register at 20, so I don't know what my final low CYA amount really was). As soon as my CYA dropped to that 20 or under value I had to drastically up my SWCG % from 20-25% at 8 hours to as high as 40%. This is with the pool being open only a few hours a week. My chlorine would drop much quicker with the lower CYA - enough to go below my target a couple of times. Once I upped the CYA back to just 30 my FC went back above target and I could lower my SWCG % back to my usual range. Most of last year I ran the CYA at 30 and everything was fine. Just last week I upped the CYA back to 40 for the summer, and even with warmer weather, warmer water, and some actual swimming my FC is now staying a little higher than before the addition of CYA last week.

Here is some of what I have read (and I am no expert) - having a higher CYA when using the SWCG allows the freshly made chlorine gas, as it works its way into solution (your pool water), to be a bit more protected. All of the proper chemistry terms confuse me a bit - hypochlorous acid and hypochlorite and what and when it actually will bond to the CYA - at some point in the process, as the chlorine is being created by the cell, it is not yet bound to the CYA - that reaction takes a certain amount of time. By having the CYA higher there is more CYA ready to bond to that freshly created chlorine and therefore buffer it properly before the sun can get it.

In addition, the chlorine is being created in small amounts over an extended period of time which is why the SWCG FC target amount can be a little bit lower - fresh chlorine is always, or more frequently, being produced - compared with manual chlorine additions. Since the FC doesn't rise and dip over time nearly as much as it does with manual chlorine additions the target number can be lower. Further, with a covered pool the sun can not degrade the chlorine before it gets bound to the CYA - so that is why I go with a lower CYA amount.

The sweet spot for FC with a SWCG is 4.5% of the CYA according to the numbers Chem Geek helped develop. Personally, like a few others on this site, I tend to run the FC just a little bit higher to be extra safe, so I usually aim for around 10% of my CYA value. Right now my CYA is 40 and my target FC is 4.

Edit: Your pool is looking great by the way!! Hopefully you can get your yard done soon and really enjoy your pool and get your life back!!!

 

[dunginhawk]

So a little clarification... My PBs right hand man (new this year) didnt know what the PB just told me . He puts in a Lot of CYA at the end of each year when he closes the pools. That CYA lasts through the entire next summer... So he actually does do CYA, but I guess just doesnt when he builds new throughout the year... strange...

So the cell is showing green, so I know the salt level is at least adequate .. Im going to do a full water test here this afternoon and list the results in a new thread (this one was just about CYA).

So next week things should really be wrapping up.. the deck is getting its wrap in siding, and roof in car siding pine planks.. Fireplace/TV wall is being built, landscape and sod going in as well. End of next week could be a whole new back yard

 

[kchinger]

Dont go adding all the salt at one time. Test your salt levels first and Aim for 2800ppm and slowly go up. My IC likes anything between . 2800-3000, any higher and you can start to taste the salt. If the light is green is good to go.

You say that like it's a bad thing? My wife and family and folks don't mind the taste, feels like the ocean!

 

[dunginhawk]

To me, just seeing a green light is less satisfying than knowing my number is accurate... I dont want to check the green light all the time to see if its on... id rather dial it in and know its good for a long time...
Salinity ended up being 3k, so thats good enough for me

 

[SBall]

Running a SWG with extremely low CYA is basically the same as manually adding liquid chlorine daily. Chlorine levels are going to have much larger swings due to just about anything imaginable...sun, clouds, bather load, cover or not, rainstorm, temperature, etc. SWG output will likely need to be adjusted every few days, and maintaining a constant FC level will be challenging. You are just going to have to mess around with it a lot. I tried this option (had CYA 40-50ish), and I just got tired of it. It was a headache. I would either have FC of 15 or 1. Levels varied tremendously on a daily basis.

Running a SWG with extremely high CYA puts a huge strain on the generator in terms of having to run at high output for very long periods of time, and might not even be able to keep up.

Running a SWG with CYA in the target range of 70-80 provides a way to maintain a much more constant FC level. I increased my CYA to 70, and now test my chlorine a couple times a week and it is between 5-7.

I think most people are plenty capable of testing the water and adjusting the SWG output on a daily basis. Nothing wrong with it, but IMO, that really takes away the value of the SWG. The point of a SWG is to "set is and forget it"...or at least "set it and not have to worry as much". I guess the other way to look at it is that maintaining CYA of 70-80 provides the most "value" out of the SWG in terms of longevity, constant FC levels, less risk of dropping too low, and overall, just much less of a pain in the behind.

 

[duraleigh]

An excellent post from Sball. IMO, think we should all suggest he post more often.

 

[dunginhawk]

Agree.. very well said... The whole idea (and reason I got SWG) is because I wanted a much easier way to manage chlorine...
thank you...