CYA in a sock

[waterbear]

I have to get something off my chest. Mods, move or delete this if you feel it's appropriate.

I have to say something about the so called 'sock method'. This really started becoming the norm on a different forum (on which I was one of the mods) and someone decided that it was the preferred method of adding CYA because you could still backwash your filter if needed and they felt it was important to get CYA in the water to clear a green pool. (I am talking about private discussions between the moderators and administrators in a hidden section of the forum. The idea was that all advice given would be consistant.)
I was the lone voice of dissent there, as was often the case (and also the only one with experience in more than just my own pool in this group of moderators and administrators). The consensus was that most people would be adding CYA when clearing a green pool and that to give more than one method would confuse pool owners (which, IMHO, shows about as much respect for pool owners as many pool stores do). What happened is that something as simple as adding CYA became another 'procedure' to complicate pool care.

So the idea that CYA needed to be put into a sock and hung in front of the return became the norm over there instead of only in those few cases where you were trying to add CYA while clearing a green pool.
However, if you read the instructions on most of the containers of CYA it says to pour it slowly into the skimmer. A few say to predissolve it in warm water and add to the pool but CYA does not really dissolve in warm water (or cold water) very quickly so that just does not work.

[polyvue]

However, if you read the instructions on most of the containers of CYA it says to pour it slowly into the skimmer. A few say to predissolve it in warm water and add to the pool but CYA does not really dissolve in warm water (or cold water) very quickly so that just does not work.

Please move this post as necessary -- it's a response to waterbear's, above.

I'm pretty sure I don't have "magic" cyanuric acid yet my experience is that when the cya is added to the skimmer it dissolves very quickly (I define "very quickly" as 10 minutes or less). Typically 2 lbs of cya is weighed out and then poured into a gallon or two of warm (90 degree F.) water, stirred up to make a slurry, then poured into the skimmer all at once with the basket in place, 75-100% suction. It's immediately evident in the pump basket but dissipates at the same rate as that in the skimmer.

I find it a bit disconcerting that my experience would seem to contradict the reports of so many others.

[aylad]

Putting CYA in a sock is a recommendation that we've been making on this forum for years, even before the other forum that you're alluding to ever existed. We do not recommend it as the sole way to add CYA; however, most of the people we have this discussion with are also having filter issues, and that's why the sock is being recommended. We may have gotten lazy about pointing out the other methods, but I remember as many posts instructing people to put it into the skimmer and not backwash for a week as I do about putting it into the sock.

Many of the labels on CYA containers (at least around here) instruct users to broadcast it directly into the pool. Personally, I have a problem with this method. I also hesitate these days to have people put it into the skimmer if I'm not positive that they'll dilute it first--I have firsthand knowledge of a pool where too much CYA was put into the skimmer all at one time and it formed a plug in the pipes, resulting in broken pipes and concrete replacement. So...I'm not sure what about this is bothering you, but CYA in a sock is a perfectly reasonable way to get it into the pool. Not because it's the only way, but because it's really the easiest.

Janet

[waterbear]

Please move this post as necessary -- it's a response to waterbear's, above.

I'm pretty sure I don't have "magic" cyanuric acid yet my experience is that when the cya is added to the skimmer it dissolves very quickly (I define "very quickly" as 10 minutes or less). Typically 2 lbs of cya is weighed out and then poured into a gallon or two of warm (90 degree F.) water, stirred up to make a slurry, then poured into the skimmer all at once with the basket in place, 75-100% suction. It's immediately evident in the pump basket but dissipates at the same rate as that in the skimmer.

I find it a bit disconcerting that my experience would seem to contradict the reports of so many others.

NO contriditions. A 'slurry' is not the same as 'dissolved' . It is still getting caught in your filter and slowly dissolving over the next several days.
YOu would see the same if you poured it slowly into the skimmer and allowed it to 'slurry' there.

[waterbear]

Putting CYA in a sock is a recommendation that we've been making on this forum for years, even before the other forum that you're alluding to ever existed. We do not recommend it as the sole way to add CYA; however, most of the people we have this discussion with are also having filter issues, and that's why the sock is being recommended.

EXACTLY! It's from this forum the use of a sock was taken (we had QUITE a discussion about it over there!) and then made into the ONLY correct way to do it. I am just saying that, unless you ARE having filter problems, it is entirely unnecessary!

[sturev]

I think I read a post about liquid CYA being available now...? To me, that's the easiest :D I recall something about it being more expensive though...

[waterbear]

I think I read a post about liquid CYA being available now...? To me, that's the easiest :D I recall something about it being more expensive though...

QUITE a bit more expensive in fact.
1 gallon Liquid Conditioner raises 10000 gallons about 35 ppm and costs close to $30 online.
2.75 lbs CYA raises 10000 gallons about 35 ppm, 4 lbs costs between abut $10 and $20 online.

do the math

[sturev]

Wow, that is pricey... Does it still take a week or so to start working/showing? If it starts right away, it might save some money in bleach...

[waterbear]

Wow, that is pricey... Does it still take a week or so to start working/showing? If it starts right away, it might save some money in bleach...

It is supposed to work my faster BUT if you filter 24/7 for a day or two after adding CYA it starts showing up pretty quick, at least enough to protect the chlorine.

[Poconos]

Polyvue,
A couple months ago I tried dissolving a couple cups of CYA granules in a gallon jug. Nope. Some did, most didn't. Kept pouring off the concentrated liquid into the skimmer and refilling and eventually after a couple weeks the solid was almost dissolved. Certainly didn't dissolve in 10 minutes. The granules are fine enough they will easily, or quickly, get past the skimmer and pump baskets. Once they make it to the filter how do you know how long they take to dissolve? I don't use the stuff personally. I smash up pucks.
Al

[waterbear]

Polyvue,
AOnce they make it to the filter how do you know how long they take to dissolve?
Al

By putting in a known amount that will cause a certain ppm rise and testing the water. I have found that it usually takes anywhere from 48 to 72 hours of constant circulation for my CYA to reach the levels for which I dosed.

[PoolDoc]

Waterbear;

I'm not sure it's reasonable to try to settle the sock vs skimmer issue the way you think. The reason is 1 word: Intex!

There are now more Intex, or Intex type, pools out there than all the commercial pools and all the inground pools put together. And last time I checked, they don't have skimmers!

I bought one once, to try it. And, we tried to put the stabilizer in to the sidewall suction intake. We ended up with stabilizer all over the bottom of the pool.

There's at least one other reason to use a sock, besides a missing or broken skimmer: cal hypo feed systems!

Do you know what happens when you mix wet stabilizer with cal hypo? If not, don't try it: it DETONATES!

I've experimented with it a little, but it scares me, so a little is all. But, you haven't lived till you've stood in a pump room, biting your nails as you listen to a 60" steel sand filter that sounds like it's full of popcorn popping!

================================================== ============

You've also raised a larger issue, of variable and even wrong advice given here. It's an issue I'm aware of, and it concerns me.

There is no perfect solution.

Even if I wrote up a comprehensive guide to BBB pool care, and let you and Chem Geek and mods proof and correct it . . . it still wouldn't be perfectly correct: I'd just think it was, for awhile.

I do hope to put together a series of FAQs for the PoolForum over the winter. But, whether I'm able to do so depends on a number of things I'm not fully in control of . . . including my own ability to concentrate on such things for hours at a time.

I do see posts and responses that make me wince. But, if I try to jump into all of them, other things more critical to PF's survival will grind to a halt. I think the question for me is, are people generally better off coming here and following the advice here, or not?

I think the answer -- imperfect responses notwithstanding -- is still clearly "Yes!".

After the past 4 or 5 years, I find that fact a lot easier to be comfortable with than it used to be. The world's a broken place, and I'm a broken person, and I can't change that. If my efforts make it a little less broken than it was, well, I think that's enough reason to be content. Not that I don't want to make it better, but I'm more able now to try to do what I can, today, and worry less about the things I can't do, at least not today.

Ben
"PoolDoc"

[CarlD]

I would like to add another note. That other forum you mentioned seems to like to latch on to one method of doing things and stick to that.

I remember being told quite clearly NOT to recommend my Shot Glass method of OTO dilution because they didn't want owners to be encouraged to use anything by FAS-DPD for chlorine, since FAS-DPD is really the best way. OK. Their forum, their rules.

That's their style and chosen modus operandi. A simple path with simple steps you don't need to choose from. One way, and only one way to do things. That's fine for them. It works for their site. It's not necessarily wrong, either.

But it's not our style here at Pool Forum and has never been. We are much more of the mind-set that if it works, and isn't dangerous, and we list all the caveats, there's no reason to discourage its usage.

There are LOTS of reasons why a particular technique (like the sock) may be the best way, but also where it may not. It took over TWO WEEKS for about a pound of CYA to dissolve into my pool in an old stocking my wife donated. It was right over the low return, too. I was patient but annoyed. Now I'm thinking it should have been in the skimmer.

Yet when I had an Intex, I had to dissolve CYA in a five gallon bucket, pour off what dissolved, refill, stir, wait, pour off...took over a day, but I didn't have CYA on the bottom. There, a sock would have been MUCH easier.

We will always be proponents of multiple paths to get to the same goal. All of us, Ben, Lisa, Janet, Al and myself ALL realize that while there are many WRONG ways to do something, there is generally more than one RIGHT way to do it, too!

All of us will always be looking for effective alternative methods that fit unusual circumstances. Please don't worry that we are going to adopt that "Only one way, the best way" style. It's just not us.

[waterbear]

Carl,
I was not worried about that here since I know Ben would put a stop to it fast but I frequent several forums and 'putting CYA in a sock' seems to be on it's way to becoming a TEKTAT. That is my real concern. (And I have been one of the first to say use a sock when the situation warrants it. Just not for the routine addition of CYA into a a pool with a skimmer.) As far as Ben's concern of calcium hypochlorite feeders, I do agree, but this is not a piece of equipment normally seen on residential pools. And I am aware that the intex donuts do not come with a skimmer. Heck, I sold enough of them and held customer's hands when they set them up. I usually recommended a set amount of dichlor to get the CYA up to speed in those cases. It dissolves fast and chlorinates at the same time.

[CarlD]

I LIKED my Intex donut! I always said that on a hot, lazy afternoon, in a floating pool chair, with a cold drink, the ball game on the radio, and shades, you can't tell the difference between a donut and a big pool! And that's experience talking.

How's that old saying go? "Don't sweat the petty things, and don't pet the sweaty things!"

(But I like my 40' FantaSea a lot more! :D )

[PoolDoc]

Waterbear,

Adding CYA in a sock would only be a TEKTAT if people here were saying that that's the only way. If anyone is doing that, I'd like to know about those threads. I haven't seen the posts in question, so feel free to email me some links of ones you think I should check out (poolforum AT Gmail DOT com)

On the other hand, to say "probably the best way (for you) to add CYA to your pool is to use a sock" is not a TEKTAT.

There have been some really clueless people here this season. I haven't had to deal with then, because the mods have done it. And I know you end up getting a mindset of "I'll tell them this, because it's simple, and they probably won't be able to figure out a way to screw it up". That's not a TEKTAT.

If sometimes someone who wasn't quite at that level of clueless got told to use a sock, maybe that wasn't ideal, but heck, it still worked (I guess) and they can learn to use a skimmer later.

And, I don't have any problem with you adding, "But you can use a skimmer, too" posts to those threads. I'd just ask that you make sure, before you do, that the OP is not one of those posters who's struggling to figure out where the water goes. :rolleyes:

If they are, that might not be the best place for a "use the skimmer" addition.

Thanks for your help on this!

Ben

[polyvue]

Polyvue,
A couple months ago I tried dissolving a couple cups of CYA granules in a gallon jug. Nope. Some did, most didn't. Kept pouring off the concentrated liquid into the skimmer and refilling and eventually after a couple weeks the solid was almost dissolved. Certainly didn't dissolve in 10 minutes. The granules are fine enough they will easily, or quickly, get past the skimmer and pump baskets. Once they make it to the filter how do you know how long they take to dissolve? I don't use the stuff personally. I smash up pucks.
Al
Well, my CYA is a bit low so I guess it's time I do an experiment. It's been my belief for some time that when CYA is added to my pool it can be detected in a fraction of the time suggested by those here and elsewhere... in hours, not days or weeks. But I'm conservative when adding chems and haven't tried to increase CYA 20 or 30 ppm all at once; perhaps I've been misled due to the imprecision of the test. The turbidity test doesn't exactly lend itself to the task.

And, even if the experiment supports my thinking (that all or nearly all of the CYA will be evident in testing within a few hours of application) I don't know how transferable this finding would be. Everyone's (IG) pool plumbing is a bit different, filter capacity, flow rates and head vary, etc.

So, I'll try to resolve this during the week, starting tomorrow night, by raising CYA 20 PPM. Got lots of melanine stored up. What the heck! :)

[waterbear]

Got lots of melanine stored up. What the heck! :)

err, melamine.

[CarlD]

I used to have a lot of melamine--but then we threw out my mom's 1950's unbreakable dishes....I hope they didn't get ground up and put into dog food! :eek:

[AnnaK]

My experience, for what it's worth:

Monday, 6/28, 06:30
ph 7.6
CYA 30 (consistent with previous tests over the past 4 weeks)

CYA goal 50. Per Pool Calculator, add 946 g CYA.

The CYA I use is mfg'd by Seaboard, 100% cyanuric acid, granular. I added 500 g slowly into the skimmer, basket removed, made sure all product was granules, no clumps. The 2-speed pump ran on 'high'. The CYA swirled in the pump pot for 15 - 20 minutes until it had all gone into the filter. At that point I set the pump to low and left it running.

According to the Pool Calculator, 500 g CYA in my pool would decrease pH by .2 and increase CYA by 11 ppm.

Tuesday, 6/29, 08:30:
pH 7.4
CYA 45

I can readily accept the difference in test results from the calculated expectation because a) the water volume can ever be just a close guess and b) variations in the 'endpoint' of the CYA test.

My past experiences with adding CYA product have been similar: it dissolves faster than what I had read and it's measurable within 24 hours.

[Watermom]

All this may be true for your pool. My experience has been that it takes longer for my pool to get up to the reading that I aim for when I add cya. So, although in some pools it may be in there and measureable fairly quickly, for some pools that doesn't always appear to be the case. Therefore, when I answer posts, I will still continue to advise people to wait awhile before testing again (to save reagents) or adding more. Better to be a little patient that overshoot a target of cya since it could mean a partial drain and refill.

Thanks for sharing!

[chem geek]

Personally, I've used an old T-shirt put into the skimmer and then added CYA on top of that shirt in the skimmer. It is important to note that my skimmer has a pipe going into the pool (looks like a return below the skimmer inlet) so that any skimmer clog will pull in water from the pool (and not crack the skimmer). I also have two floor drains so even if the skimmer and it's separate pipe to the pool were clogged, the pump would still be able to pull water from the floor drains.

So for me this works best as it is easy to do. The CYA dissolves in a matter of hours, usually overnight and certainly less than 24 hours. As for CYA measurement thereafter, at least 2/3rds of it registers after it dissolves (tested 24 hours after my last addition to the skimmer) and it could be more, but I don't usually add more than 20-30 ppm and target a CYA of 30-50 ppm so errors in measurement play a significant role here.

When CYA is added to the skimmer without a T-shirt, panty-hose, skimmer sock, etc. then it gets caught in the filter. The water velocity in the filter media itself is MUCH slower since it is spread over a much larger area. This is why it takes longer for the CYA to dissolve using this method. For my oversized cartridge filter with four 85 square foot filter cartridges, even with the pump at 48 GPM for my solar (it's 26 GPM with no solar), over 340 total square feet of cartridge area the water velocity is around 0.2 inches per second. In my skimmer (with no CYA in it that obviously blocks the flow significantly), assuming 15 GPM and a 1 foot diameter skimmer area the flow rate is about 2" per second.

Those that use a sock over the return should probably periodically squeeze the sock to break-up and mix-up the material inside. I think that a sock over the return is far better than simply broadcasting the CYA around the pool, but I think that putting the CYA into the skimmer either with a T-shirt/panty-hose/skimmer sock filter or without (to get caught in the filter) are very reasonable alternatives. Just make sure the filter isn't backwashed too soon -- the recommendation to wait a week should be fine (or if a CYA test shows that it is all dissolved).

Richard

[PoolDoc]

Hadn't thought about the water velocity thing -- makes sense.

Ben

[polyvue]

Precursor: http://www.poolforum.com/pf2/showthread.php?p=64969#post64969

CYA Application Experiment June 29, 2010

Though I was fully prepared to retract my rash assessment before doing this experiment (and may still have to if my pool turns out to be 9 or 10K gallons instead of the 14K gallons I believe it is) it appears that I have been conservative in my estimation that CYA dosing shows up in testing in a few hours instead of a few days. I think preliminary testing shows that there is nearly full dissolution in less than 60 minutes.

Procedure

Using the Pool Calculator (http://www.poolcalculator.com/), 37 ounces (wt) of cyanuric acid (stabilizer) should increase CYA by 20 PPM and effect a reduction in pH of .37

Predict CYA 50 PPM and pH 7.33

I weighed the CYA granules on a postal scale and split into two batches, making a one gallon slurry from each and adding one right after the other into the skimmer (basket in place). Granules disappeared from both skimmer basket and pump basket in about 6 minutes. Water samples were drawn from the same location in the pool (midway between shallow and deep end) and about 18 inches from the surface. I used a 44 mL sample and 5 drops R-0004 phenol red indicator titrant for the pH test; and a 14 mL sample tube (7 mL sample and 7 mL cyanuric acid reagent) for the CYA test. All sample tubes and collectors were rinsed before testing with sample water and afterward with tap water. The CYA samples were each shaken for 20-30 seconds and titrated into a 9 mL view tube immediately. The temperature of collected sample water was 89° F . At no time was I wearing socks. :)

Test Results

BEFORE ADDITION
pH 7.7
CYA 30 PPM

AFTER ADDITION
15 minutes
pH 7.5
CYA 40 PPM

30 minutes
pH 7.4
CYA 45 PPM

60 minutes
pH 7.4
CYA 50 PPM

120 minutes
pH 7.4
CYA 50 PPM

24 hours (water temp 87° F)
pH 7.5
CYA 50 PPM

48 hours (water temp 84° F)
pH 7.6
CYA 50 PPM

Epilogue 7/1/2010

In less than one hour 37 ounces of CYA added to the skimmer basket was fully testable (within the limits and precision of the titrated turbidimetric test offered by Taylor). Possible contributors to this rapid absorption: size/speed of pump; clean, oversized cartridge filter (12 PSI); high flow rate and velocity, resulting in quick turnover of pool water (< 3 hours); short run from application point to equipment pad; method of application (warm water and vigorous mixing of slurry, operation of automated pressure-side cleaner, water features, spa overflow); elevated pool water temperature (about 88-89 degrees F.) That’s all I can think of. The implications are: In small pools with warm water, great circulation and a clean filter, the CYA may break down, most of it dissolving in as little as 1/3 of the turnover time.

Questions? Scoffs? Rebukes?

[waterbear]

Precursor: http://www.poolforum.com/pf2/showthread.php?p=64969#post64969

CYA Application Experiment June 29, 2010

Though I was fully prepared to retract my rash assessment before doing this experiment (and may still have to if my pool turns out to be 9 or 10K gallons instead of the 14K gallons I believe it is) it appears that I have been conservative in my estimation that CYA dosing shows up in testing in a few hours instead of a few days. I think preliminary testing shows that there is nearly full dissolution in less than 60 minutes.

Procedure

Using the Pool Calculator (http://www.poolcalculator.com/), 37 ounces (wt) of cyanuric acid (stabilizer) should increase CYA by 20 PPM and effect a reduction in pH of .37

Predict CYA 50 PPM and pH 7.33

I weighed the CYA granules on a postal scale and split into two batches, making a one gallon slurry from each and adding one right after the other into the skimmer (basket in place). Granules disappeared from both skimmer basket and pump basket in about 6 minutes. Water samples were drawn from the same location in the pool (midway between shallow and deep end) and about 18 inches from the surface. I used a 44 mL sample and 5 drops R-0004 phenol red indicator titrant for the pH test; and a 15 mL sample tube (7 mL sample and 7 mL cyanuric acid reagent) for the CYA test. All sample tubes and collectors were rinsed before testing with sample water and afterward with tap water. The CYA samples were each shaken for 20-30 seconds and titrated into a 9 mL view tube immediately. The temperature of collected sample water was 89° F . At no time was I wearing socks. 

Test Results

BEFORE ADDITION
pH 7.7
CYA 30 PPM

AFTER ADDITION
15 minutes
pH 7.5
CYA 40 PPM

30 minutes
pH 7.4
CYA 45 PPM

60 minutes
pH 7.4
CYA 50 PPM

120 minutes [pending]
pH - - -
CYA - - - PPM

24 hours [pending]
pH - - -
CYA - - - PPM

I’ll edit this post to update the last two entries as they become available.

Questions? Scoffs? Rebukes?

I have performed similar experiments and it has taken about 36 hours with pump running for the full amount to show in the best test I had. Then again I was not testing evey hour since it's a waste of reagent, IMHO

Also, by my calculations it should take 37.3 oz of CYA to raise 14k gallon by 20 ppm (and I don't use the pool calculator) so we agree there. Have you verified that your pool is 14k?(There is a way to chemically determine the gallonage of the pool using a modification of the Taylor TA titration to give you a result of 1 ppm and baking soda if you are interested) If not then the experiment should be carried out with testing for a few days until the CYA no longer rises to make sure you have reached the endpoint of your experiment
.
Also the water flow has a lot to do with how quickly it dissolves so this is definitely a case of YMMV. FWIW, when i have used a skimmer sock and put the CYA in that it stayed in the sock for a few hours before there were no traces left. Also, water temp will play a small part here since CYA is very slightly more soluble in hot water(but again, the difference is slight.)
Also, as anyone who has ever broadcast CYA in the pool can attest to, it stays on the bottom for around 6 hours before it seems to disappear. Once again, I believe the water flow, or lack thereof, plays a factor here.
There are really just too many variables which is why it is safe to say retest in a week. This ensures that the CYA has dissolved and that you are not wasting reagent (although those that sell test kits often want you to waste reagents and have to buy refills).


I always told my customers to add it, wait a week and then retest but I always assumed that they were getting at least some protection from UV by the next day.

What I don't get is those that are so afraid of CYA that they add such small quantities for the size of their pool that are barely measurable and wonder why it does not seem to rise. If you overshoot the CYA by 10 ppm it is not the end of the world and probably will have no impact on how you have to care for your pool (Even if you miss the magic number of 50 ppm and end up at 60!) The test is subjective at best so we are really only ballparking it anyway.

[chem geek]

I weighed the CYA granules on a postal scale and split into two batches, making a one gallon slurry from each and adding one right after the other into the skimmer (basket in place). Granules disappeared from both skimmer basket and pump basket in about 6 minutes.
I want to be clear I understand this. So the slurry of CYA didn't have the CYA dissolve much and when you poured this into the skimmer you didn't have any skimmer sock, panty hose or T-shirt, right? So the CYA didn't all go through the small skimmer holes right away and that took around 6 minutes -- was that for each addition or 6 minutes for both gallons combined?

I wonder how long it would take for some CYA to dissolve in a tube with a magnetic stirrer (I know some of you out there have one)?

[polyvue]

I want to be clear I understand this. So the slurry of CYA didn't have the CYA dissolve much and when you poured this into the skimmer you didn't have any skimmer sock, panty hose or T-shirt, right? So the CYA didn't all go through the small skimmer holes right away and that took around 6 minutes -- was that for each addition or 6 minutes for both gallons combined?
Actually, there was quite a bit dissolved in the time it took to add warm water, stir it up and deliver it to the skimmer. The slurry was pretty cloudy so I would guess that about a quarter of the granules had partly or completely dissolved before being poured in. No skimmer sock or any other material in place -- just the skimmer basket. 2 consecutive applications of about 1 gallon each were poured in 30 seconds apart (I followed each with a bucket of pool water to ensure that the granules adhering to the sides were flushed into the basket). It was at that point that I thought to set my timer and kept an eye on the skimmer while the granules escaped/dissolved. I didn't see any granules left at about 5 minutes and only a few in the pump basket -- they too disappeared, about a minute later. So, I'd say 6-7 minutes elapsed from the moment I finished adding the second bucket. During the 6 minutes I entertained myself by varying suction from 0 to 100%, but most of the time it was at mid-point (50% main drain, 50% skimmer).

I should note that the last time I checked there were a few granules (20?) lodged in the transparent Jandy Energy Saver Filter that was mis-plumbed in the water feature (deck jet) return line. This is pretty typical. If I don't run the jets they'll sit there for weeks or months, undisturbed.

[polyvue]

I have performed similar experiments and it has taken about 36 hours with pump running for the full amount to show in the best test I had. Then again I was not testing evey hour since it's a waste of reagent, IMHO

I have too much reagent. :D

Also, by my calculations it should take 37.3 oz of CYA to raise 14k gallon by 20 ppm (and I don't use the pool calculator) so we agree there. Have you verified that your pool is 14k?(There is a way to chemically determine the gallonage of the pool using a modification of the Taylor TA titration to give you a result of 1 ppm and baking soda if you are interested)

Have gone to great pains to estimate pool volume, including Free Chlorine and Total Alkalinity titrations (I have pages of notes on the latter if anyone is tired of Seinfeld re-runs), geometric summations, various formulae (including one you authored for estimating spa volume, posted on I forget which forum).... of course, all this effort just made me less sure about the correct volume! :(

If not then the experiment should be carried out with testing for a few days until the CYA no longer rises to make sure you have reached the endpoint of your experiment.

Point taken. We'll see what tomorrow brings.

Also the water flow has a lot to do with how quickly it dissolves so this is definitely a case of YMMV. FWIW, when i have used a skimmer sock and put the CYA in that it stayed in the sock for a few hours before there were no traces left. Also, water temp will play a small part here since CYA is very slightly more soluble in hot water(but again, the difference is slight.)

Yes, I suspect the velocity of the water (elaborated by chem geek in an earlier post), flow rate and temperature have a lot to do with it. I recognize that my pool has a comparatively high rate of circulation and turnover. I don't claim to have overturned any physical law or to have procured magic cya beans that dissolve faster than the usual stock of cya commonly available.

There are really just too many variables which is why it is safe to say retest in a week. This ensures that the CYA has dissolved and that you are not wasting reagent (although those that sell test kits often want you to waste reagents and have to buy refills).
Yes, it's safe (and in some forums, seems to be the law) to suggest waiting "at least a week" before testing CYA. But, like the "filter for a minimum of 8 hours" rule, there are evident exceptions. For good or for ill, my pool seems to be one.

[CarlD]

Our only "laws" are against promoting things that are down-right dangerous because they cause injury, disease or go "Ka-BOOM!!!". We are particularly wary of things that leave you in danger while lulling you into a false sense of security.

Also anything that is not legal or questionably legal is a big no-no here.

[waterbear]

Have gone to great pains to estimate pool volume, including Free Chlorine and Total Alkalinity titrations (I have pages of notes on the latter if anyone is tired of Seinfeld re-runs), geometric summations, various formulae (including one you authored for estimating spa volume, posted on I forget which forum).... of course, all this effort just made me less sure about the correct volume!


If you have not used this method you might want to give it a try. It works.
http://www.poolhelp.com/ChemicallyDerivedPoolVolumes.pdf

Here is the link for the "“Simplified Formula Numbers” chart
http://www.poolhelp.com/SimplifiedFormulaNumbers.pdf

FWIW, this is the chart I use to calculate dosage amounts for chemicals by using the formmla:
(Volume of pool / "forumula number" for desired chem from chart) x ___ ppm desired change = ___ pound or quarts of desired chem needed

SO for a 14k pool where you want to increase CYA by 20 ppm it is
(14000/120000)x20=
.1167x20=2.33 lbs. CYA
2.33lbs x 16 oz/lb =37.28 (which rounds to 37.3)

[CarlD]

Oh, I forgot: The other BIG law here:

No selling stuff. Period. Ever. No exceptions.

So...what kind of sock is best? Hanes? Gold Toe? Athletic Nikes? Ladies' pantyhose? Colored or white?

I have these great Tilley brand travel socks--soak them in a sink and they dry in 2 hours--"Two pairs will take you around the world!" How do they work?

I mean, how can you compare the "Sock" vs "Skimmer" method unless you can get hard info on how different socks perform?

[AnnaK]

Great links, Evan. Thanks!

[waterbear]

So...what kind of sock is best?

I have always had a preference for seamed nylons on a shapely leg.:cool::cool:

[AnnaK]

All this may be true for your pool. My experience has been that it takes longer for my pool to get up to the reading that I aim for when I add cya. So, although in some pools it may be in there and measureable fairly quickly, for some pools that doesn't always appear to be the case.



You make a great point, Lisa: all pools are different. They are dynamic systems which change with the environment in which they live. Type of pool, type of equipment, fill water, use, weather, location, surroundings . . . the list is endless. As well, the way a pool is managed depends on the owner's knowledge, skill, understanding of pool water chemistry, attention to detail and so forth.

In the end, the goal we all strive for is to have well balanced water and that, ultimately, is the goal of this forum: to assist pool owners, via the sharing of experiences and observations by other pool owners, the coming together of myriad methods and techniques with the clear caveat that not everything works for everybody or every pool.

Thanks for helping me make that point.

[polyvue]

If you have not used this method you might want to give it a try. It works.
http://www.poolhelp.com/ChemicallyDerivedPoolVolumes.pdf

Here is the link for the "“Simplified Formula Numbers” chart
http://www.poolhelp.com/SimplifiedFormulaNumbers.pdf
[...]
Yes. This is the source for the formula I used in the spring when estimating volume via Total Alkalinity. Even this technique has its drawbacks but it requires absolutely no vector calculus, an advantage for those of us whose mathematical aptitude and/or enthusiasm declined sometime before or during Calc I.



I mean, how can you compare the "Sock" vs "Skimmer" method unless you can get hard info on how different socks perform?
You're correct; no attempt at a comparison was made. Nor could I figure out how to introduce a meaningful control (having run out of duplicate in-ground free-form swimming pools that were designed and built to my specification); and, besides another test in the same pool, how does one evaluate the repeatability of this experiment?

As Evan pointed out earlier (and AnnaK, above), too many variables. Perhaps my hand was shaking when I titrated (perhaps my hand always shakes but I'm unaware).

[CarlD]

I have always had a preference for seamed nylons on a shapely leg.:cool::cool:


:eek:
TMI, Evan, TMI! ;)

[waterbear]

:eek:
TMI, Evan, TMI! ;)

I don't mean MY leg!:eek:

[Watermom]

You guys are crackin' me up!:D

[CarlD]

I don't mean MY leg!:eek:

That's a relief--but still TMI! :D

(but we got Lisa laughing! :D )

[polyvue]

Let's see if this revised post has legs....

http://www.poolforum.com/pf2/showthread.php?p=65145#post65145

[waterbear]

The implications are: In small pools with warm water, great circulation and a clean filter, the CYA may break down, most of it dissolving in as little as 1/3 of the turnover time.

Questions? Scoffs? Rebukes?

Very possibly but since this is not the majority of pools out there it is not information that I would call universally useful. It is useful to you in your own pool (and interestingly enough, does not apply to my small (under 7k) pool that I keep at 88 degrees year round and that has an oversize cart filter also and an oversized pump (because of the spa), and turns over in about 2 hours. It just shows that pools need to be taken individually and the guidelines to test after a week will be useful to the vast majority of pool owners.

You have to agree that a 'universal truth' is going to be much more useful than a whole lot of individualized ones and less error prone.

[polyvue]

Very possibly but since this is not the majority of pools out there it is not information that I would call universally useful. It is useful to you in your own pool (and interestingly enough, does not apply to my small (under 7k) pool that I keep at 88 degrees year round and that has an oversize cart filter also and an oversized pump (because of the spa), and turns over in about 2 hours. It just shows that pools need to be taken individually and the guidelines to test after a week will be useful to the vast majority of pool owners.

You have to agree that a 'universal truth' is going to be much more useful than a whole lot of individualized ones and less error prone.
“Universally useful” is a strict criterion, the application of which I’d best leave to others more qualified in the sock/skimmer/stabilizer and chemistry departments. I’ve only proved to myself that the guideline (“Wait one (1) week before testing CYA”) is not an axiom.

Al said that it took a couple of weeks for CYA to completely dissolve in a gallon jug (unagitated, I presume). Richard found that 2/3 of the CYA he added in the skimmer was detectable within 24 hours; without a t-shirt/sock to hold the CYA, it would find its way to the cart filter and take longer to dissolve due to reduced velocity. (I don’t use any material to trap the granules in the skimmer but I don’t take issue with this: I think velocity and temperature are key. My procedure involves stirring the CYA slurry enthusiastically for the two minutes it takes to fill the bucket with warm, almost hot, water until it’s poured into the skimmer.)

There are others in the forum who have observed very rapid dissolving of CYA but they fear arrest and imprisonment so I won’t “out” them. ;)

I’m glad you took issue (would this be a scoff or a rebuke?) with my conclusions. Your expertise and experience helps me narrow the field. If some or all of the contributing factors I speculated to be causal in the rapid dissolution of the cyanuric acid in my pool can be ruled out, what is left? What explains the phenomena?

If it can be determined that factors x and y are most responsible for accelerating the process, perhaps we can also devise a procedure (or revise an existing one) to effect a rapid introduction of (granulated) CYA into the water so that no one need wait 7 days to confirm their stabilizer level. This would be useful, would it not?

Greg