concerns regarding closing at shock level

gwtw

Well-known member
Apr 23, 2018
78
Kentucky
My pool professional wants to add an oxidizer, PH buffer, and a stain inhibitor to my pool before closing. From reading this forum, I know that I don't need these things since my pool is clear and balanced, so I told him that I would handle the chemicals myself this year. My water is already 60 degrees so I was planning on just closing at shock level, which is 20 ppm and skipping the optional polyquat. When I told him that I was planning on closing at 20 ppm and adding nothing else, he told me that it wasn't wise to close with that high of a chlorine level because it will bleach out and deteriorate my mesh cover. He also said that he didn't think the chlorine at this level will last that long in our climate since we often have mild winters with little snow or freezing weather. I can't afford to replace my cover anytime soon and I dont want to open up to a neon green pool so I wanted to see if my pool pro's arguments against closing at shock level were valid or not. If the chlorine could possibly bleach my cover or won't last very long in my climate, I will use polyquat instead but I definitely won't be adding the chemicals my pool pro suggested.
 

duraleigh

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He is likely not taking into account the buffering effect CYA has on FC. 20 FC with a CYA of 50 will have no bleaching affect on your cover.

Personally, I would not use polyquat, either but, with a mesh cover, figure out how I could add some bleach from time to time so FC stays in the pool.

I think you are on the right track and I think your pool pro is simply "old school" and hasn't learned yet about the FC/CYA relationship
 

Catanzaro

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Jul 30, 2014
3,322
Monmouth County, New Jersey
I am an advocate of using Poly60, only when the pool is being closed earlier than usual. No need for anything but what Dave suggested. Your chlorine will last quite a while, especially in this weather. If you open up early, surprisingly, you may find that the pool still has chlorine in it. You are only looking to maintain the chlorine until the deep freeze (or real cold weather), algae will not grow in real cold conditions, and you will be fine as long as you open the pool by last week of April.

Think about it, a winter closing kit that only consists of bleach that costs less than $7.50 and you are done. No harm will be done to the pool cover and your pool will only be green if you have a mesh safety cover and you wait too long to open the pool in the Spring. A lot of pool owners open their pool one week prior to the holiday and wonder why it is green, not being able to use it for the holiday weekend.
 

jimim

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Jun 20, 2016
2,373
NE/Pa
Lots of good info here. I have a mesh cover also. I opened this year March 1st and just maintained the pool. That way I knew my water was still very cold 42 degrees actually and didn’t have to worry about the warmer weather sneaking up on me. I know the hard freezes were pretty much over or at least I knew the frost line was gone.

What i did ad it warmed up was, and u are st ur own risk but I had zero issues, I dropped a pump at the bottom of my pool with a 4 foot hose attached to it with metal end cut off so it didn’t ruin plaster. I let it run so the hose whipped around to pull and push water out to get movement in the pool. I dumped my chlorine slowly in the deep end with pump and let it run for 4 hours. Measured in deep end for level and then 2 places in shallow end. They matched. I know I was good. That kept me safe to the point I didn’t worry about anything growing before I opened.

I know others here here will say not to do it but I know builders who come and dump chlorine in and just mix it with a brush without any issues. I feel I got way better mixing how I did it. You can do the same if u r afraid before the ice gets on. I did in late November before we had ice to bring it back to where I was at.
 

Catanzaro

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Jul 30, 2014
3,322
Monmouth County, New Jersey
That is super early. I would have at least waited until the end of March and then turned the pump on. With weather being still cold, you could literally get away with running the pump for 1 hour daily, just to mix things up. My pool gets opened once the back yard is spotless as not to get anything crazy in the pool. Everyone has to find what works best for them.
 

gwtw

Well-known member
Apr 23, 2018
78
Kentucky
I really don't want to mess with adding more chlorine later this fall or in the early spring before we open. It is just really hard to get the loop locks on and off and I think it would be difficult to get the chlorine distibuted around the pool well enough with a brush unless a lot of those loop locks are removed. If I used polyquat instead, would it keep my pool algae free longer without having to add any chemicals to the pool before opening in late April or early May?
 

Catanzaro

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Jul 30, 2014
3,322
Monmouth County, New Jersey
I really don't want to mess with adding more chlorine later this fall or in the early spring before we open. It is just really hard to get the loop locks on and off and I think it would be difficult to get the chlorine distibuted around the pool well enough with a brush unless a lot of those loop locks are removed. If I used polyquat instead, would it keep my pool algae free longer without having to add any chemicals to the pool before opening in late April or early May?
No need to add more chlorine once the pool is closed. If the closing is around October 15th (even with the mesh cover) and pool is opened by last week of April, there is a very small probability you will even open up to a green pool. Even if you had a little bit of algae, the SLAM would go very quickly (maybe in 2 days). Put the pool to rest and relax for the next few months and concentrate on other more important things.

UPDATE:

As Zea3 mentioned, the water temperature should be in the or near 60 degrees. If we have a very hot October, then the pool closing should be delayed a few more weeks. My closing was this Saturday and water was about 62 degrees from what I can tell.
 
Last edited:

zea3

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Jul 10, 2009
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Have you closed this pool before? Do you have iron or high calcium in your source water? How far do you plan to lower the water level?

He is adding a non-chlorine oxidizer, we advocate chlorine as your oxidizer. The fact that it is an oxidizer is what has the potential to damage a pool cover. That does not mean it will damage your pool cover. Your pH is only going to rise so far, and with a fiberglass pool you probably won't see any pH rise at all. If you have high calcium then you might need some stain and scale inhibitor, but probably not.

The secrete to opening with clear water is close late, when water temps are consistently below 60, and open early, before the water hits 70. The mesh pool cover shades the water and keeps a lot of the sun off, so your FC loss to UV rays will be minimal. If the pool is clean and no organics get in it won't use up much FC there. As long as the FC lasts over the winter you have good odds of opening clear.