Closing chemistry recommendation

[CarlD]

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

[FormerBromineUser]

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

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.

[Watermom]

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

[CarlD]

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

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.

[SunnyOptimism]

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

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!!

[JimK]

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.

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?

[JimK]

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

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

[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.

[JimK]

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.

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.

[Watermom]

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.)