Did SLAM prior to winter closure of pool - after 1.5 weeks, FC has only dropped back down 6.5ppm. Why so slow and should I just continue to wait?

just4747

Well-known member
May 20, 2024
67
CT
Pool Size
12000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Following the pool closing outline here: Closing an In Ground Pool

...cleaned my pool well, backwashed filter/added new DE, and then with SWG off, brought it up to SLAM level with 12.5% liquid chlorine on Oct. 24th. Pool started at 60 CYA/14.5 FC (FC was higher than normal due to less sun and no pool usage here now in CT, and SWG had been running), so I had to bring it to about 24 FC for SLAM, per the charts.

It took about 2 days for the FC to stop losing ppm overnight, and then finally stayed level at 24ppm overnight on morning of Oct. 26th.
Since then, I have basically been waiting, SWG still off, and keeping the pool clean and running the filter (tons of leaves falling in every day now, a nightmare), testing FC every few days.

Now today, about a week and a half after finishing the SLAM, the FC has only dropped about 6.5ppm, sitting at 17.5ppm. CYA is around 50-55. Pool is in only partial sun during several hours per day, uncovered, and SWG remains off, no chlorine being added.
It is dropping extremely slowly. Am I doing something wrong here? I can find barely any instances of it taking THIS long for FC to drop back to normal levels after a SLAM, which to me doesn't make sense since it is happening to me. I had planned to let FC drop back to approx. normal levels for my pool, depending on CYA at the time (e.g. if CYA is 50 then wait for FC to drop to, say 5ppm), since I plan to use Algaecide/Polyquat 60 and read that it isn't compatible with high chlorine levels. OR should I be getting my CYA back up higher like its normal range for my pool (closer to 70ish and then get FC to say, 7ish?

Either way, the FC is dropping so slowly and it has been a while now, so not sure what I should be doing.

All FC testing is using TFTestkits FAS-DPD testing and reagents not expired. Pool water gathered using long PVC pipe in deep end, 10 mL in chlorine cylinder, one level scoop of R-0870 powder using the small blue scoop, and magnetic auto stirrer.
What should I be doing at this point, if anything different? Thanks.
 
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Add the Polyquat 60, let it circulate for 24 hours, and close your pool.

Your FC is dropping slowly since the sun UV is approaching the lowest of the year. Days are shorter and the sun angle is lower. The lowest UV day is only about 6 weeks away.
 
Add the Polyquat 60, let it circulate for 24 hours, and close your pool.

Your FC is dropping slowly since the sun UV is approaching the lowest of the year. Days are shorter and the sun angle is lower. The lowest UV day is only about 6 weeks away.
I want to just close it but I read several times not to use Polyquat with higher than normal levels of chlorine and mine is pretty high right now (not even dropping halfway back to normal yet).
Is this not accurate?
 
I want to just close it but I read several times not to use Polyquat with higher than normal levels of chlorine and mine is pretty high right now (not even dropping halfway back to normal yet).
Is this not accurate?
I don't know where you read that.

You are trying micro manage things.

It is better with a lower level of chlorine and will be good enough where you are.
 
I don't know where you read that.

You are trying micro manage things.

It is better with a lower level of chlorine and will be good enough where you are.
I read it in several threads here when researching winterizing. The guide itself doesn't mention it but other places did, many times from knowledgeable people here.

What do you mean micro-managing? I am just trying to go by instructions and suggestions, like everything else with pool stuff here. Chlorine level isn't micro-managing to me?

My chlorine is still very high for my setup so it is definitely not low at the moment.
 
Do as you want if you do not like my advice after 60,000 posts.

What guide are you referring to? Here is the guide...

The one I linked in the first post. The general winterizing outline and there is another similar post here too with bookmark links at the top but same info.

But other threads that came up from TFP on Google had people saying to not have high chlorine when using Polyquat. I can find them again if needed.
 
But other threads that came up from TFP on Google had people saying to not have high chlorine when using Polyquat. I can find them again if needed.

I don't need them. Do you?

From the manufacturer of Polyquat 60. What more do you need?

Buckman Labs says that even if the Polyquat is broken down, it is still effective when used as an algaecide. Moderate to high levels of chlorine break down Polyquat but it still only transforms the formula into shorter chain polymers that are still just as effective.
 
I don't need them. Do you?

From the manufacturer of Polyquat 60. What more do you need?

Buckman Labs says that even if the Polyquat is broken down, it is still effective when used as an algaecide. Moderate to high levels of chlorine break down Polyquat but it still only transforms the formula into shorter chain polymers that are still just as effective.
The link you yourself just posted above says the same thing I'm saying for the most part, right above that part:

If you raise your water to SLAM FC level then you should let the FC drift down before adding Polyquat 60. Having a moderately higher level (½ SLAM level so the FC/CYA ratio of 20%) is okay as well. The idea is that the Polyquat should last through the winter even if the chlorine does not.[12]

Are you telling me to ignore that part? Why?
I'm still well above even half SLAM, let alone normal levels.
 
The link you yourself just posted above says the same thing I'm saying for the most part, right above that part:

If you raise your water to SLAM FC level then you should let the FC drift down before adding Polyquat 60. Having a moderately higher level (½ SLAM level so the FC/CYA ratio of 20%) is okay as well. The idea is that the Polyquat should last through the winter even if the chlorine does not.[12]

Are you telling me to ignore that part? Why?
I'm still well above even half SLAM, let alone normal levels.

You seem to like to select the snippets that support what you want to believe.

What does the next paragraph say?

I will interpret that paragraph for you - even if you use PQ60 with higher levels of chlorine it still only transforms the formula into shorter chain polymers that are still just as effective.

BTW, I wrote that Wiki page.
 

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You seem to like to select the snippets that support what you want to believe.

What does the next paragraph say?

I will interpret that paragraph for you - even if you use PQ60 with higher levels of chlorine it still only transforms the formula into shorter chain polymers that are still just as effective.

BTW, I wrote that Wiki page.
I mean you can say same thing for the opposite belief too lol - someone may read either paragraph alone (or both) and interpret one way or the other, since the first one literally says to drop the FC and the second turns around and says it's ok if you don't - kind of contradicting.
I wasn't saying I don't believe you or anything, but I've just read several different things now (again, in other threads too), and was starting to get confused/unsure, that's all.

Thanks for the info, I will make my best judgement using that article and the other threads.
 
, but I've just read several different things now (again, in other threads too), and was starting to get confused/unsure, that's all.

This is the Internet. Would you expect anything less?
 
I mean you can say same thing for the opposite belief too lol - someone may read either paragraph alone (or both) and interpret one way or the other, since the first one literally says to drop the FC and the second turns around and says it's ok if you don't - kind of contradicting.
Interesting that you read it that way and choose to read each paragraph independently.

Since I wrote it I will tell you that the first paragraph is intended to tell you that is the best way to do it. And the second paragraph says if you don't do it the best way the manufacturer, Buckman Labs, says it will still turn out fine.
 
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