Closing chemistry recommendation

I have researched AND researched pool closing chemistry. After due diligence, here is my recommendation for IG vinyl liner with solid cover, freezing winter, and algae-free balanced water:

1) 2-3* nights before closing: Vacuum/brush and backwash if needed. Bring to shock level.

2) 1-2* nights before closing (next night): Add 60% polyquat at "visible algae" dose.

3) Night before closing: Check floor for debris, check filter pressure; adjust as needed. Raise FC back to shock level. Circulate 2 hours and lower level to below skimmer.

4) Close mechanics however you wish.

* Some people differ as to waiting 24 or 48 hours after polyquat addition. If waiting 48 hours, check FC after 24 hours to be on the safe side. Polyquat will lower fC.

I wonder about the effectiveness of Polyquat additions in high FC pool water. Typical a high FC will cause the polyquat polymer to become cleaved into shorter fragments. It's not clear that the effectiveness of the polyquat is degraded but the recommendation is to add the polyquat after the FC comes down to "normal" levels.

I'm not arguing with your methodology, just wondering if there's a better point at which to add the polyquat?

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Originally Posted by SunnyOptimism

I wonder about the effectiveness of Polyquat additions in high FC pool water. Typical a high FC will cause the polyquat polymer to become cleaved into shorter fragments. It's not clear that the effectiveness of the polyquat is degraded but the recommendation is to add the polyquat after the FC comes down to "normal" levels.

I'm not arguing with your methodology, just wondering if there's a better point at which to add the polyquat?

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I'd love to know the answer to this. I plan on closing later next week. :(

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Originally Posted by SunnyOptimism

I wonder about the effectiveness of Polyquat additions in high FC pool water. Typical a high FC will cause the polyquat polymer to become cleaved into shorter fragments. It's not clear that the effectiveness of the polyquat is degraded but the recommendation is to add the polyquat after the FC comes down to "normal" levels.

I'm not arguing with your methodology, just wondering if there's a better point at which to add the polyquat?

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That is not MY recommendation.
I bring FC up to shock level, and when it holds there, add a quart of Polyquat.
I wait 48 hours, during which time FC plummets due to the Polyquat.
I then raise FC back up to shock level and close.
I always open to a clear pool unless I wait too long after the ice melts in the spring.

Somewhere ChemGeek responded to this issue after talking with one of the 'manufacturers' of polyquat. I believe he said that the shorter threads still do their job. But understanding ChemGeek is not my speciality!!!!

See this post where you can read the procedure from Buckman Labs. They also told me that when chlorine oxidizes Polyquat into smaller pieces, they are still fairly effective. They just won't act as much like a clarifier, but can still inhibit algae growth.

Ah, you wrote in English. ;) Your response was just basic enough for us non-chemgeeks to understand.

It is important information for those of us who ponder using polyquat on closing. The clarifying properties seem pretty insignificant at the end of the season.

I would love to see this info put out there for easier access on the Pool Forum.

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Originally Posted by chem geek

See this post where you can read the procedure from Buckman Labs. They also told me that when chlorine oxidizes Polyquat into smaller pieces, they are still fairly effective. They just won't act as much like a clarifier, but can still inhibit algae growth.

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My winter closing procedure and spring opening results is a demonstration of that.

So here's how I'm reading the info in this thread-

You bring you water to shock level to clear it.

You wait some amount of time and then add polyquat

You wait a little longer and then raise your FC again and close.

The problem I see is that, based on the manufacturers recommended process, if you follow the CYA/FC relationship (as you should) then your shock level of FC is definitely going to cleave the PQ into smaller subunits unless you wait long enough after shock level for the FC to drop below 10ppm. If you look carefully at what the manufacturer says, they say to shock up to 5-10ppm and then "wait a few days" before adding the PQ. That tells me that the PQ is definitely going to cleave.

I guess the ultimate question is, at what FC does PQ start to cleave into smaller fragments and at what FC is the PQ's algaestatic properties completely destroyed? That last part would set the upper bound of how much FC you can have in the water when you add the PQ. Add the PQ too soon after raising the FC to shock level and you risk the chlorine burning up all your PQ.

Interesting stuff here.....

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Originally Posted by SunnyOptimism

So here's how I'm reading the info in this thread-

You bring you water to shock level to clear it.

You wait some amount of time and then add polyquat

You wait a little longer and then raise your FC again and close.

The problem I see is that, based on the manufacturers recommended process, if you follow the CYA/FC relationship (as you should) then your shock level of FC is definitely going to cleave the PQ into smaller subunits unless you wait long enough after shock level for the FC to drop below 10ppm. If you look carefully at what the manufacturer says, they say to shock up to 5-10ppm and then "wait a few days" before adding the PQ. That tells me that the PQ is definitely going to cleave.

I guess the ultimate question is, at what FC does PQ start to cleave into smaller fragments and at what FC is the PQ's algaestatic properties completely destroyed? That last part would set the upper bound of how much FC you can have in the water when you add the PQ. Add the PQ too soon after raising the FC to shock level and you risk the chlorine burning up all your PQ.

Interesting stuff here.....

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I was wondering about that also.

Not me. I've been using an effective method of closing for over a decade.

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Originally Posted by chem geek

They also told me that when chlorine oxidizes Polyquat into smaller pieces, they are still fairly effective.

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And the question is???

If you want the assurance of an algaecide on closing, and also want to close with shock level FC, this is your answer. "Fairly effective" sounds like a plan.

Doesn't seem like allowing FC to drift down before adding polyquat makes a big difference when you close at shock level because your FC will still attack the PQ.

And, remember, it isn't required to use polyquat upon closing. I never do.

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Originally Posted by Watermom

And, remember, it isn't required to use polyquat upon closing. I never do.

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That's right. We use what has worked for us consistently. I use polyquat, Watermom doesn't. We both open to clean pools.
Who is right? Both of us.

So it would seem that the PQ can and will be oxidized by the high chlorine BUT the likely outcome of that oxidation is just smaller fragments of PQ not degraded biocidal activity. FC could potentially destroy the PQ but probably not until you reach some ridiculously high FC concentration that would likely never be found on a residential swimming pool.

Ok, you all have convinced me to close my pool using polyquat....oh wait, my pool never closes :p

Seriously though, I now understand PQ usage better so if I had a need for it in the future, like an Ascorbic acid treatment, I'd feel a lot better prepared about how to use it.

Thanks all for your insights!!

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Originally Posted by CarlD

That's right. We use what has worked for us consistently. I use polyquat, Watermom doesn't. We both open to clean pools.
Who is right? Both of us.

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Might this indicate that the polyquat is unnecessary for closing, at least if you close late and open early?

If I remember correctly, both of you close once the water temp drops below 60 and open before it gets much above 60? Perhaps in this case just shocking is sufficient?

I imagine the type of cover used also factors into when to close/open. I know you use a mesh cover and Watermom uses none. I use to use a mesh cover and discovered it was important that I close/open according to water temp (60) like you and Watermom. Since using a solid cover, it doesn't seem important when I close or open. One year I didn't open until about June 10th (waiting on liner repair) and the water was still clear when I removed the cover.

Btw, last year my closing method was shock, wait a day, add polyquat (1 qt) and cover (solid cover). Water temp was in the mid 60's when I closed (early October) and close to 70 when I opened (early May). Water was clear.

I'm just wondering if adding polyquat is really helping or am I just wasting money. Perhaps since I keep about 60ppm borates in the pool and use a solid cover adding polyquat is unnecessary?

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Originally Posted by Watermom

And, remember, it isn't required to use polyquat upon closing. I never do.

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Do you add any chlorine during the time between closing and opening?

I don't know. It's possible the PQ is a waste. $20-$25. But if it's not, then AT LEAST $20 in chlorine's going in to clean up a spring bloom.

I don't add chlorine over the winter--tough when there's a foot or more of ice. Occasionally, if necessary, I can sneak a thin plastic hose between the ice and the wall, in a corner, and drain of excess water due to rain and snow melt.

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Originally Posted by CarlD

I don't know. It's possible the PQ is a waste. $20-$25. But if it's not, then AT LEAST $20 in chlorine's going in to clean up a spring bloom.

I don't add chlorine over the winter--tough when there's a foot or more of ice. Occasionally, if necessary, I can sneak a thin plastic hose between the ice and the wall, in a corner, and drain of excess water due to rain and snow melt.

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Yeah, I was thinking about trying closing without PQ, but then if the experiment fails, the cost of cleanup, not to mention the extra effort, would likely be much more than the cost of a quart of PQ.

I keep my equipment hooked up in the fall, adding bleach occasionally as necessary. When we start getting freezing temps at night, which is usually in November for us, I then drop the water level, shock the pool, take my pH up to around 7.9 and unhook equipment. Then I'm done for the winter. I do open up early -- probably in April. It gets hot early here. We can typically swim in early May. (I have not used polyquat for many years.)

I am in central Va, closed several weeks ago using high chlorine, followed by a heavy dose of poly and then letting pump run for approx. 48 hours and vacuuming. Now my water is black. Did I simply close too early? First year pool owner btw. I have trees on 3 sides so I know that doesn't help. Watermom, opening in April and never covering your pool how do you deal with pollen?

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Originally Posted by zmanh

Watermom, opening in April and never covering your pool how do you deal with pollen?

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I just use my net and skimmer to clear the pollen from the pool. Not a big deal, really. The skimmer gets most of it although I don't run the pump when I am not home to keep an eye on the skimmer basket.

As far as your pool ----- polyquat will drop the chlorine level pretty quick. So, if you didn't add more chlorine after the polyquat addition, you probably didn't have much chlorine in there. That combined with the water temperature not being very cold yet are most likely why you are now having an algae problem.

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Originally Posted by zmanh

I am in central Va, closed several weeks ago using high chlorine, followed by a heavy dose of poly and then letting pump run for approx. 48 hours and vacuuming. Now my water is black. Did I simply close too early? First year pool owner btw. I have trees on 3 sides so I know that doesn't help. Watermom, opening in April and never covering your pool how do you deal with pollen?

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Did you cover the pool? If so, with a solid or mesh cover?

If going coverless, or even a mesh cover, you need to wait until water temp stays below 60.

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Originally Posted by JimK

you need to wait until water temp stays below 60.

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And, even below 60 degrees is no guarantee that algae won't grow. Somewhere here on the forum is a picture posted by Poconos (a former moderator) where he has ice on his pool with algae growing below it. I'll see if I can find it but it was a long time ago so probably won't be able to.

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Originally Posted by Watermom

And, even below 60 degrees is no guarantee that algae won't grow. Somewhere here on the forum is a picture posted by Poconos (a former moderator) where he has ice on his pool with algae growing below it. I'll see if I can find it but it was a long time ago so probably won't be able to.

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Yikes!

Thanks for the reply. I was getting plenty of questions from my wife on why I hadn't closed yet. (both neighbors had) And I honestly couldn't answer it, so I ended up closing. Know better next year. I am using a mesh cover, since I don't have a cover pump. Plus I have plenty of leaves to deal with so didn't want those getting on cover, getting wet and weighing it down. I have plenty of tree trimming to do this winter to hopefully remedy that. On behalf of those of us that may not comment as much, thank you all at the pool forum. I made a few mistakes my first year. (had no idea how much of an effect 12 kids taking swimming lessons would have on chlorine drop) I paid for that by spending the next 2 weeks fighting algae. The threads, stickies, articles, etc. were very helpful.

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Originally Posted by zmanh

Thanks for the reply. I was getting plenty of questions from my wife on why I hadn't closed yet. (both neighbors had) And I honestly couldn't answer it, so I ended up closing. Know better next year. I am using a mesh cover, since I don't have a cover pump. Plus I have plenty of leaves to deal with so didn't want those getting on cover, getting wet and weighing it down. I have plenty of tree trimming to do this winter to hopefully remedy that. On behalf of those of us that may not comment as much, thank you all at the pool forum. I made a few mistakes my first year. (had no idea how much of an effect 12 kids taking swimming lessons would have on chlorine drop) I paid for that by spending the next 2 weeks fighting algae. The threads, stickies, articles, etc. were very helpful.

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I didn't find this site until after several seasons of trying to figure out why the pool store's recommendations weren't working. Now, by following the recommendations here, maintenance is much easier and cheaper. :)

Since you're using a mesh cover, I suggest you plan to open in early March. Here on the VA coast I found if I opened later than that (when I was using a mesh cover) I had a good chance of opening to a green pool. Since using a solid cover, I've not had a green pool in the spring even opening as late as early June. You're right though, the solid cover does get messy.

You said you don't have a cover pump. Since you have a mesh cover, you will still need a pump to drain excess water that will accumulate in your pool during the winter. And since all that rain will dilute your pool water, you should probably plan to add another dose of polyquat, perhaps in January or early February.

I also have trees around my pool. In the fall, I just stay after removing the leaves that fall in the pool by using a leaf rake and also my Polaris 65 which does a great job at picking up big stuff such as leaves. Then, once the trees have dropped all the leaves, the water stays clear.

I never liked covering my pool. First of all, I hate looking at a covered pool. I would much rather look at my water. Secondly, on a 27' pool, the cover is HUGE and a real pain to deal with. It was hard to clean off in the spring, difficult to fold up and store and when I would remove it in the spring, the mix of disintegrating leaves and nasty water would inevitably end up in the pool murking up the water that had remained clear over the winter.

So, several years ago, I just decided to not fool with the cover. Now, over the winter, I don't have to do anything with the pool at all. No hassling with using a sump pump to pump nasty water off the cover. I have not regretted my decision to not cover the pool at all.

:puzzle:
I've read this entire thread plus other helpful closing information on the site. THANK YOU!

My question: When you refer to raising the FC to shock level to close, at what point on the "Ben's Best Guess Guide to Swimming Pool Chlorine" are you shocking? There are two 'Shock' columns with very different Shock levels. Should we use the higher shock numbers for winter closing?

No. Use the lower value, I believe the left of the 2 columns. I do not recommend you closing your pool until any algae bloom is clear. Then raise to the lower shock level.
If your CYA level is below 10, use 10 as your shock level
Below 30, use 12.
Below 60, use 15,
Below 100, use 20,
100 or above, use 25.

Last I saw was that your CYA was around 40 but were thinking about raising it. Did you? The number on the far RIGHT of the chart are only for mustard algae; extreme cases.

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Yesterday 10:12 PMCarlD
Re: Closing chemistry recommendation

No. Use the lower value, I believe the left of the 2 columns. I do not recommend you closing your pool until any algae bloom is clear. Then raise to the lower shock level.
If your CYA level is below 10, use 10 as your shock level
Below 30, use 12.
Below 60, use 15,
Below 100, use 20,
100 or above, use 25.

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Thank you, Carl. That's exactly what I needed. Leaves are still falling off of the trees here, and the temps are occasionally dipping below freezing at night. I'm not using a cover this winter. Too expensive just to have the wind rip it to shreds by the end of closing season. Nobody makes a cover that fits, or is meant to stay on, an AG vinyl sided Intex pool (that I can find) anyway.

I truly appreciate your quick response.

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Originally Posted by FormerBromineUser

Last I saw was that your CYA was around 40 but were thinking about raising it. Did you? The number on the far RIGHT of the chart are only for mustard algae; extreme cases.

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My CYA did raise, but it wasn't necessarily intentional. I began using Dichlor from Sam's in lieu of bleach. My CYA kept raising. I went back to bleach once it reached 70. Didn't want it to get any higher. So it stands at 70 as of today. I had a hard time keeping my pH down this summer. ??? Anyway, it's good at 7.9 now. TA=80. CC=0. Water temp is 45*.

Thanks for letting me know what the high shock level is used for.

For every 10 ppm Free Chlorine (FC) added by Dichlor, it also increases the Cyanuric Acid (CYA) by 9 ppm.

Kinda makes you wonder why more people don't use dichlor to raise CYA instead of the slow-dissolving sock treatment!

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Originally Posted by FormerBromineUser

Kinda makes you wonder why more people don't use dichlor to raise CYA instead of the slow-dissolving sock treatment!

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One advantage of using the straight CYA instead of dichlor is that is easier to know right off the bat the dose needed to get to a desired CYA level.

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Originally Posted by Watermom

One advantage of using the straight CYA instead of dichlor is that is easier to know right off the bat the dose needed to get to a desired CYA level.

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+1

I'm one of those who prefer to use straight CYA. ;)

I have never used it. This was my first year even having CYA and I used dichlor. It was very easy. Straight CYA just sounds like a pain... Squeezing a dangling sock, waiting around a week to verify results. Hmmm.

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Originally Posted by FormerBromineUser

I have never used it. This was my first year even having CYA and I used dichlor. It was very easy. Straight CYA just sounds like a pain... Squeezing a dangling sock, waiting around a week to verify results. Hmmm.

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I don't use the sock method. Also doesn't take a week to verify results. At least that's been my experience with my pool.