Adding CYA to the skimmer, or not

[ETS]

Split off of Increasing CH and CYA, which order and best application. JasonLion

I would reccomend putting the CYA in a filter sock, used panty hose, or something similar and place the contents in your skimmer basket. It takes time to dissolve. Pouring it directly into the skimmer and allowing it to come to rest in your filter in undissolved form could damage it. It is, after all, an acid.

 

[frustratedpoolmom]

Re: Increasing CH and CYA, which order and best application

Plenty of users pour it directly into the skimmer, plenty use the sock method. I'm unaware of any reports of damage to the filter caused by adding CYA to the skimmer. I could see it causing damage if the pump were off, and the water in the filter housing became very low in PH, but the CYA will dissolve quickly enough I don't think this is an issue with normal filtration times.

 

[ETS]

Re: Increasing CH and CYA, which order and best application

I respectfully disagree. And I forgot to mention that dumping it directly into the skimmer like that can also damage your pump.

 

[duraleigh]

Re: Increasing CH and CYA, which order and best application

ETS,

In the seven years I have owned my pool and been on these forums, I am not aware of anyone reporting damage from introducing CYA thru the skimmer......including me as I have done so at least 5 or more times.

Do you know of real world anecdotes where that has occured? Can you explain what damage occurs?

 

[frustratedpoolmom]

Re: Increasing CH and CYA, which order and best application

I respectfully disagree. And I forgot to mention that dumping it directly into the skimmer like that can also damage your pump.

Well then somebody needs to tell the manufacturers at Malibu....the following is from the label on the side of the cannister of CYA I bought at American Sale last week....

"Add this product through skimmer while filter and pump are operating. Do not stop pump for at least 12 hours to give all the materials a chance to dissolve."

I think if there were real risk to the equipment, these folks would be advising other methods and/or putting warning labels on their bottles of chems. JMHO.

 

[ETS]

Re: Increasing CH and CYA, which order and best application

Hi all.
I am an employee at a Pinch A Penny store in central Florida. We are trained to never add granular chemicals of any kind directly to the skimmer. Also to never add any acidic or corrosive liquid chemical there either. All chemicals are to be dissolved first.
The reasoning is long term damage and the shortening of the life of the pump and filters. I'm sure you have all heard of the long term damage to equipment that high levels of chlorine can cause.
Pump gaskets, seals, and O-rings are all sensitive to high concentrations of acidic and corrosive chemicals. Deterioration of these lead to premature pump leaks which in turn leads to well premature failure.
Also, adding granular chemicals to the skimmer can clog the pumps impeller and lead to further problems there. That is one of the reasons DE powder (which is very fine) is added slowly to the skimmer and not dumped in all at once.

Go to the web site "PumpED 101" and read the articles on cavitation. They describe and document the damage that imploding air bubbles can do to a pumps impeller. If air bubbles can do that kind of damage, what do you think granular chemicals might do?

Having said all that, I have noticed that alot of you are from northern states where your pool season is relatively short and that you close your pools during the winter. Here in central Florida our pool systems run year round so we experience a lot more wear and tear on our systems. That may explain the difference in the recommendations for adding chemicals to a pool. We repair a lot of pumps and filter systems every day and we also do pool resurfacing. Our techs are pretty familiar with the damage these chemicals do on pool surfaces and pumps etc., but again, you may not experience as much wear and tear as we do.

 

[JasonLion]

As a general rule, avoiding adding chemicals directly to the skimmer is a good thing. However, of the common pool chemicals, only muriatic acid poses a significant risk to the pump/filter/etc. When the pump is running, large amounts of water are flowing through the system and the various chemicals get diluted quite quickly. Only muriatic acid is concentrated enough that it still poses an obvious risk when added through the skimmer.

People have been adding CYA to the skimmer for years and years. The great majority of CYA packaging specifically instructs you to add it to the skimmer. Huge amounts of CYA have been added through the skimmer, all without any significant problems showing up. That is not to say that damage is impossible, just very very rare.

Quoting lots of technical information about possible damage tends only to get people scared. Hardly anyone is likely to follow what you are saying. Scaring people about trivial issues like the extremely minor risk of pump damage from CYA is counter productive. If you want to scare people, scare them about not bothering to add any chlorine to the pool and swimming anyway (way too common in my experience), or having an unsafe main drain, or running an extension cord to an electrical device floating in the water (people actually do this sometimes, as hard as that is to believe).

Using a sock in the skimmer is not really all that different from adding CYA directly. These days CYA is produced as very small grains that are clumped into larger grains. The larger grains break up into the very small grains quite quickly, usually within an hour, and then pass through the sock and end up in the filter anyway. There are some minor theoretical advantages, you don't have the large grains passing through the pump, but in both cases the CYA ends up in the filter until the smaller grains dissolve, which takes many hours to days.

 

[Guest]

Re: Increasing CH and CYA, which order and best application

Hi all.
I am an employee at a Pinch A Penny store in central Florida. We are trained to never add granular chemicals of any kind directly to the skimmer. Also to never add any acidic or corrosive liquid chemical there either. All chemicals are to be dissolved first.

Blatantly untrue. CYA is what is known as a 'weak acid' chemically. It will not cause any major change in pH. Adding baking soda (TA increaser) will not cause problems either. All other chemicals should be predissolved. Also, many pool stores (don't know if Pinch a Penny does or not since I don't frequent them since I worked for a competetor) recommend putting trichlor tablets in the skimmer. THAT is a recipe for disaster since it's akin to pouring acid into the skimmer. The problem is that it seems that the are simplifying your training since most pool store employees have a limited, if any, understanding of chemistry!

The reasoning is long term damage and the shortening of the life of the pump and filters. I'm sure you have all heard of the long term damage to equipment that high levels of chlorine can cause.
Pump gaskets, seals, and O-rings are all sensitive to high concentrations of acidic and corrosive chemicals. Deterioration of these lead to premature pump leaks which in turn leads to well premature failure.
Yes, I agree if you are referring to the all too common practice of putting trichlor (which is very acidic, unlike CYA) into the skimmer!

Also, adding granular chemicals to the skimmer can clog the pumps impeller and lead to further problems there. That is one of the reasons DE powder (which is very fine) is added slowly to the skimmer and not dumped in all at once.
No, DE powder should NEVER be added directly to the skimmer, unless you want to clog your pipes. It should be mixed into a 'slurry' with water first and then slowly introduced into the skimmer. Anyone who has ever serviced DE filters should know this but then again, most pool store employees have not (and many do not even own pools!)

Go to the web site "PumpED 101" and read the articles on cavitation. They describe and document the damage that imploding air bubbles can do to a pumps impeller. If air bubbles can do that kind of damage, what do you think granular chemicals might do?
You are comparing apples and oranges here.

Having said all that, I have noticed that alot of you are from northern states where your pool season is relatively short and that you close your pools during the winter. Here in central Florida our pool systems run year round so we experience a lot more wear and tear on our systems. That may explain the difference in the recommendations for adding chemicals to a pool. We repair a lot of pumps and filter systems every day and we also do pool resurfacing. Our techs are pretty familiar with the damage these chemicals do on pool surfaces and pumps etc., but again, you may not experience as much wear and tear as we do.

I have lived in Florida for most of my life and grew up in Miami, then moved to Ft. Lauderdale, and now live in St. Augustine and have been taking care of pools and hot tubs since I was a teenager (and I'm in my 50's now!) so I beg to differ with you. I have not only cared for residential pools but also commercial pools so I do speak from experience.

 

[ETS]

Wow! I expected some possible flack for my statements but not the written thrashing I have received here.

Look, first of all I am not trying to scare anyone and the very last thing I want to do is pass on misinformation to anyone. As I have said in an unrelated post I am the eternal skeptic. I do not believe everything I have been told by my superiors or even the corporate scientists from Pinch A Penny. After all I came to this site to try to learn the truth however conflicting that may be to my training. And to pass on any info that I may have that may help others in the process. If I inadvertingly pass on any bad info in the process I sincerely apologize. It is not intentional.

Now I am willing to listen to your arguments and theirs as both sides seem to make valid points.
Our service manager, like you, has been in the business for many years and is in his 50's. He has spent most of his years installing and repairing pool pumps and filter systems etc. He claims that he has gone to countless sites and found CYA piled up inside pump baskets where it has sat for days dissolving. This is sitting in their pumps all night long dissolving while the pump is off. Our owner, who does most of the resurfacing jobs and has been doing it for years and says he has seen the damage CYA does to pool plaster first hand. So if it can damage pool plaster, can it not damage the gaskets and O-rings inside your pump? That is if it's clumped in the pump basket and just sitting their dissolving? And you've said yourself that it takes days to dissolve.
Now I do know from my own experience that we replace a lot of pump baskets ( I mean almost every day) that are deteriorated beyond belief and we repair a lot of leaky pumps. In the 20 years that I have owned my own pool, I have never had a leaky pump nor have I ever had to replace my pump basket. Could it be they are pouring muriatic acid into their skimmers? Why would they do that? I really don't know. Maybe I'll do a survey.
Now My other colleague is an M.D.. No, that is not a typo. He really is an M.D. (long story). Has quite an exstensive background in chemistry. He swears all this is true and acurate. So he backs their claims.
So who is a poor "young" pool student to beleive :? Anyway, I will pass on your comments to them and see what they say. Cheers. ETS

 

[dlduvall]

Correct me if I'm wrong, but it seems you are talking about two different scenarios. On the one hand, the mods are talking about putting CYA in a sock and letting it dissolve out of the sock while the pump is continuously running to help circulate it as it dissolves. The sock keeps the clump from getting out to the filter undissolved. The damage you speak of in your example specifically said the pump was not running, and the cya was undissolved in the filter. That seems to indicate that the CYA was just dumped in and then the pump was not left on to circulate it. I'm a rookie, so I could be wrong.

 

[frustratedpoolmom]

Correct me if I'm wrong, but it seems you are talking about two different scenarios. On the one hand, the mods are talking about putting CYA in a sock and letting it dissolve out of the sock while the pump is continuously running to help circulate it as it dissolves. The sock keeps the clump from getting out to the filter undissolved. The damage you speak of in your example specifically said the pump was not running, and the cya was undissolved in the filter. That seems to indicate that the CYA was just dumped in and then the pump was not left on to circulate it. I'm a rookie, so I could be wrong.

Not exactly. If it's a sand filter, we tend to suggest the sock method, because of backwashing issues. But with cart filters, which aren't backwashed, the CYA can be poured slowly into the skimmer, so that the flow of water is not blocked. The pump should continue to run for a minimum of 12 hours so that the CYA can dissolve. This practice is very common and should not cause any damage. CYA can be put in sand and DE filters this way too, but since they are backwashed, if the pressure in the filter were to rise, requiring backwashing, all the CYA just added would be lost, tis why the sock is suggested for those type of filters. One may use the sock method for a cart filter too, if it makes them feel more comfortable.

Who knows what went wrong it his example, the original parties aren't present to explain what may or may not have happened.

No one is thrashing you ETS, you shouldn't take anything said personal, as you are new here and you are getting to know our personalities. I'm sure it must be an eye opening experience for you to read some of the threads on this forum....

Tis always a lively debate here in the Deepend.

 

[chem geek]

Both Trichlor and Cyanuric Acid are acidic and Trichlor is far more acidic in concentrated smaller volumes. 1 Trichlor puck of 8 ounces weight will exhaust 100 ppm TA in around 100 gallons at which point the pH initially at 7.5 crashes below 4.3 (this does not count the further pH drop when chlorine gets used/consumed) and the active chlorine level is over 150 ppm. 8 ounces of CYA in 100 gallons has the pH drop to 6.26 and the active chlorine gets much smaller. For comparison, Muriatic Acid has a pH of around -1 so even with 100:1 dilution, the pH is still a very low 1.0.

As long as the pump is running, both Trichlor and CYA dissolve relatively slowly so would not be a problem during that time. However, if CYA got caught somewhere with the pump turned off, then the local acidity could be an issue. I can see the point ETS is making if undissolved CYA got caught close to the pump and the pump were to turn off. However, even with Trichlor in a skimmer basket with the pump off, it usually takes doing this many times before problems are seen -- it's a cumulative effect. CYA addition is not nearly so frequent.

Personally, my favorite approach is to put an old T-shirt (essentially a skimmer sock) into the skimmer and add the CYA to it and keep the pump running. It usually all dissolves in less than 8 hours and when I did this recently the CYA measured at least 20 ppm out of its expected 30 ppm in that time so is truly mostly dissolved into the bulk pool water. My skimmer has an alternate flow pipe into the pool so there is no damage to the skimmer if it gets clogged (which it does when CYA is sitting on the T-shirt).

I have a cartridge filter and never really liked the idea of having the CYA mostly slowly dissolve in it. It takes far longer because the flow rate is much slower through the square footage of my oversized cartridge -- 50 GPM through 2" pipe (3.356 square inches inside area) is 4.78 feet/second, so in my 340 square foot cartridge area the flow rate is only around 0.24" per minute. Talk about slow flow!

Richard

 

[JasonLion]

I am sorry if you take it as a "written thrashing". That is not our intention. We like to debate this kind of thing, and are happy to change our opinions and recomendations if you can make a solid case for change. We do prefer to have this kind of conversation it in The Deep End, rather than in the middle of answering a question in the Just Starting area.

He claims that he has gone to countless sites and found CYA piled up inside pump baskets where it has sat for days dissolving.

I have seen this happen, the pump can even be destroyed by losing prime and overheating because the CYA blocks the flow of water. This happens when the CYA is dumped in too quickly with the skimmer basket removed. In my experience this is quite rare. If the flow of water is not completely blocked, the CYA will break apart and move on into the filter in an hour or two without any significant impact on the pump.

Our owner, who does most of the resurfacing jobs and has been doing it for years and says he has seen the damage CYA does to pool plaster first hand. So if it can damage pool plaster, can it not damage the gaskets and O-rings inside your pump? That is if it's clumped in the pump basket and just sitting their dissolving? And you've said yourself that it takes days to dissolve.

This is much more debatable in my view. There are quite a number of things that can damage the plaster, and CYA is not the most likely one. I find it difficult to link any specific plaster damage to any specific incident involving CYA. Serious plaster damage typically takes time to develop, and doesn't usually come from a single incident.

Likewise, it is difficult to link pump damage to CYA, other than the occasional broken strainer basket full of CYA. Trichlor is actually a much more likely suspect for most pump damage. Trichlor left in the skimmer will give a dramatic burst of acid each time the pump starts up. CYA is not nearly as acidic, and while it could once in a very long while sit there for days, it will do that at most perhaps twice a year, while trichlor can do it twice a day, day after day after day.

first of all I am not trying to scare anyone

Sadly, this is the effect your more technical explanation of your position will have on novices. They don't really follow what you are saying, and just hear scary words. This is why we move this kind of conversation to The Deep End.

 

[chem geek]

I PM'd ETS since we hadn't heard from him and I wanted to make sure everything was OK. Here is his response:

Hi Richard,
Glad to hear from you. And everything is ok, thank you for your concern. It is much appreciated. I haven't been responding to the board because I was laid up with a bout of bronchitis and a touch of pneumonia. Was out of work a few days and just started back today.

Anyway, I discussed everyone's comments with our service manager and our top pool guy, the M.D. He, specifically, stated that you have to consider flow dynamics and water temperature when dealing with this issue. In other words, when you have fast flowing water under high pressure such as exists inside a pump, the effects of caustic chemicals are greatly accelerated and will compensate for the limited time period for the event.
Is that significant? I really don't know. He is convinced that it is. He does acknowledge that others will disagree with him, however.

My service manager, on the other hand, reminded me of why we were trained to discourage our customers from pouring any chemicals directly into the skimmer in the first place. Most of them know absolutely nothing about pool chemistry and are frequently confusing sodium bicarb with calcium and CYA etc. And of course, I am reminded of this on a daily basis. We are a very busy store. Many of our customers are elderly and many are physically handicapped in many ways. Very few keep adequate care and cleaning of their pump baskets as they cannot remove the lids. Many don't even know they have a pump basket. Many of our customers do not speak English very well and some bring their own interpreters. So, basically, to be on the safe side we try to err on the side of caution. This is our real world!
I also consulted with one of our younger pool techs who stated flatly that if you add stabilizer granuals to your skimmer they not only can but WILL (he was very emphatic) clog your impeller. Though this clogging would only be temporary of course. Could this cause any kind of damage to the pump? I have no idea. I'll leave that one to the pump experts to argue.

All in all, I think they make some good points and I will continue to discourage our customers from pouring CYA directly into their skimmers, but I will not get too distressed about it if they do. I also will not push the issue here on these forums out of respect for you all.

Thanks again for your message, Richard and if you want to post this in the forum that's ok as I was about to do so anyway. Sincerely, ETS

The keep it simple rule of just don't add anything to the skimmer is certainly easy enough for most to remember, even if it is too conservative. The only thing you really have to add through the skimmer is the small amount of DE to sand filters when doing that addition (and I wonder what the young pool tech would say about whether this, too, can get caught in the pump impeller).

Certainly, adding acid to the skimmer is an absolute no-no, and having Trichlor pucks in the skimmer isn't good either. Adding Cyanuric Acid isn't nearly as much of a problem, but it's still worse than adding baking soda which is pretty innocuous. So it's all a matter of degree. Personally, I like adding it to a T-shirt (or skimmer sock) in the skimmer or hanging it in a sock (or stockings) over a return.

Richard

 

[JasonLion]

I am warming up to the idea of a sock in the skimmer basket. I like that better than a sock hung near a return both because hanging a sock near a return will often result it the sock sitting tight against the pool wall, and because the added complexity of figuring out how to hang it will cause some people to do stupid things.

This is one of those cases where I don't think any possible approach is really trouble free. The sock in the skimmer basket can completely block the skimmer, which could be a problem if the skimmer is your only suction port. Of course that combination isn't all that common any more.

 

[frustratedpoolmom]

I agree Jason. Thanks for sharing that Richard, ETS makes some good points about the carelessness (though unintentional) some people have with regard to their pool and equipment. IT's a shame, after putting so much money into something like a pool.

KISS and err on the side of caution.... I'll be advising the sock in the skimmer method, cautioning that it not block the water flow, leave pump running for 12-24 hours while it dissolves, etc...

 

[New2Me]

Having just done this last night, use a sock! I started to just pour some into the skimmer with the pump running,(8 lbs, this after 18 boxes of 20 Mule Team; 4.5 gal. of MA went in front of the returns, Pool Calculator ROCKS!!! ) After just a little addition, I noticed a slight change in the pump sound, so I went to look at it. The pump basket looked like a snow globe, and it sounded somewhat like a blender! I then put a skimmer sock in, and added the rest(~6 lb.s) into it. It was gone this morning. So was the 740 lbs. of NaCl that I hoped would push the wrinkles out of my new liner(unfortunately, the wrinkles remain )

I'll add the final 8 lb.s to the sock today. I have the suction set open for both the skimmer and main drain. I poured the 20MT slowly into the skimmer, and it never affected the pump, and was not visible in the strainer, so it must dissolve quickly. The NaCl gave the water a shimmer as it dissolved, it looked cool to see it creep into the drain, or shoot out of the returns!

 

[Aquaclear-NZ]

My personal preference is for not adding things to the skimmer, partly due to the fact i sell a lot of gas heaters, and for most people when an instruction reads "add slowly or do not add more than 1lb at a time" they read this as "put it all in and a bit more for good measure"

I see now there are a few manufacturers selling cyanuric acid in a 3.5" tablet, which is good for leaving in a floating tab dispensor in the pool for a slow, no mess release

 

[ReDDoG83]

I am still a noob here, but here is what I know to be true for me. Prior to adding my CYA I added shock an hour before to allow the chlorine levels to reach 3ppm or higher. I then added 5lbs of CYA to the skimmer basket. I was following the directions directly from my bottle of "Maintain" Conditioner/Stabilizer. After adding I will admit I started to panic :grrrr: I noticed the lid of my pump had turned snow white and the jet pressure inside my pool had dropped big time. :grrrr: So I kept my cool and about 10 - 20 minutes later everything was back to normal except the undisolved granules of CYA in my pump. I would also note that I leave my pump running 24/7 during the swim season. All in all, I think it is safe to add the CYA directly to your skimmer as long as you superchlorinate your pool an hour or so before (I guess this helps break down the CYA? :?: ) and to keep your pump running till the CYA has had time to fully disolve which I have read takes around 3 - 5 days. But hey, what works for me may not work for you so use your brain :-D

 

[duraleigh]

It sounds like you added the CYA a little too fast and it temporarily restricted the amount of water that was being drawn into the pump. I have done the same thing and got the same results you are describing. Like you said, no real problem. Some people make a "slurry" before putting it into the skimmer and that helps. I simply add it more slowly, now. :lol:

The chlorine neither helped nor hurt.