Mesh covered pool closing questions

[Nadadora]

Our pool guy postponed our closing to next Monday, October 23rd. I’m nervous about closing our mesh-covered pool because our water temperature isn’t below 60 degrees yet like is recommended on here and it’s going to be impossible to keep leaves out of the pool for another week since our pool has overhanging trees and it will be windy. Water temperature is currently 65 degrees and I’m not sure if it will drop much this week since highs will be in the upper 60s/low 70s and lows In the upper 40s/low 50s at night. I got FC up to SLAM level a week ago and I’m now trying to maintain it at half shock level so I can use Polyquat 60% at closing.

If I use Polyquat at closing, is it risky to close with water temperature of 65 degrees? If the water temperature hasn’t dropped below 60 by Friday, should I see if I can postpone the closing a few weeks and put the cover on to keep leaves out of the pool in the meantime? It would be a big hassle to put the cover on but we will do it if it might decrease the risk for algae.

If it wouldn’t be too risky to go ahead and close it with 65 degree water, I need to know how much polyquat to add and the best way to add it. Since I will have a lot of leaves in my pool before it is closed and it has been almost 2 weeks since I got it up to SLAM level, should I use the light algae dose printed on the bottle which is 11-17 oz per 10k gallons? Or should I add less since polyquat lowers the chlorine level? Do I need to lower the PH before adding the polyquat since the PH is 7.8 now and it tends to go down due to all of the rainfall over the fall and winter? What is the best way to add the polyquat so it gets distributed throughout the pool? What is the minimum amount of time that I should run the pump after adding the polyquat? I don’t like to run the pump at night because of the leaves but I could check the skimmer several times in the night if it is important to run the pump for 24 hours after adding it.

 

[Newdude]

If I use Polyquat at closing, is it risky to close with water temperature of 65 degrees?

You're probably close enough. Once covered the FC loss drops significantly with little UV. Algae growth is already slowing so that's working in your favor too.

It would be a big hassle to put the cover on but we will do it if it might decrease the risk for algae.

Many 'soft close' and run the pool under the cover. You can do that indefinitely. Bring it to SLAM and the FC will last quite a while, possibly a couple weeks. Take samples from the skimmer until you get a feel for how well its holding. In a pinch when 'soft opening' in the spring I used my filter air bleeder valve to fill a cup.

Pop a corner by a return to add bleach when necessary, which won't be often You can brush 16ft worth afterwards with just a small window open.

Since I will have a lot of leaves in my pool before it is closed

Don't leave debris to fester all winter. The freshly fallen leaves are harmless but if given months to decay, it'll be a mess in the spring. Vac close to covering to leave as little as possible in there.

I got FC up to SLAM level a week ago and I’m now trying to maintain it at half shock level so I can use Polyquat 60% at closing

Remember to Overnight Chlorine Loss Test

Add PQ per the bottle the day before close. I would use the light algae dose, for my large pool I used the whole bottle.

Diluting it in a 5 gallon bucket in 4 doses really helped it disperse well. Add the diluted mix in front of a return and brush after.

Do I need to lower the PH before adding the polyquat since the PH is 7.8 now and it tends to go down due to all of the rainfall over the fall and winter?

I'd leave the PH where it is if you bottom out over the winter like many of us.

What is the minimum amount of time that I should run the pump after adding the polyquat?

It says 24 hours but use your judgement if it looks good and mixed earlier from being diluted first.

 

[Nadadora]

You're probably close enough. Once covered the FC loss drops significantly with little UV. Algae growth is already slowing so that's working in your favor too.

Many 'soft close' and run the pool under the cover. You can do that indefinitely. Bring it to SLAM and the FC will last quite a while, possibly a couple weeks. Take samples from the skimmer until you get a feel for how well its holding. In a pinch when 'soft opening' in the spring I used my filter air bleeder valve to fill a cup.

Pop a corner by a return to add bleach when necessary, which won't be often You can brush 16ft worth afterwards with just a small window open.

Don't leave debris to fester all winter. The freshly fallen leaves are harmless but if given months to decay, it'll be a mess in the spring. Vac close to covering to leave as little as possible in there.

Remember to Overnight Chlorine Loss Test

Add PQ per the bottle the day before close. I would use the light algae dose, for my large pool I used the whole bottle.

Diluting it in a 5 gallon bucket in 4 doses really helped it disperse well. Add the diluted mix in front of a return and brush after.

I'd leave the PH where it is if you bottom out over the winter like many of us.

It says 24 hours but use your judgement if it looks good and mixed earlier from being diluted first.

The light algae dose printed on the bottle is 11-17 oz per 10K gallons. I’m terrible at math so could you tell me how much to add to my 18500 gallon pool? I don’t see polyquat on the pool math dosage calculator. I want to make sure I add enough of it since there has been so many leaves in my pool since it was shocked almost 2 weeks ago. If PH ends up being higher than 7.8 on Sunday when the polyquat needs to be added, should I lower it? If so, how low do I go and how long do I need to wait after adding the muriatic acid to add the polyquat?

 

[Newdude]

I'd fudge the math and double the dose.

If PH ends up being higher than 7.8 on Sunday when the polyquat needs to be added, should I lower it?

If the off season rains typically lower your PH, I'd leave it alone if it was 8.2 or lower.

 

[Nadadora]

If the off season rains typically lower your PH, I'd leave it alone if it was 8.2 or lower

I'd fudge the math and double the dose.

If the off season rains typically lower your PH, I'd leave it alone if it was 8.2 or lower.

I assume you mean that I should add between 22-32 oz then. Is it better to go with the lesser amount (22 oz) since it won’t lower the FC as much or use a higher amount since it’s been 2 weeks since doing a SLAM and my pool filled up with leaves after a storm a few days ago? Will polyquat protect my pool against algae if the FC dips down lower than minimum FC level soon after adding it and before the water temperature drops below 60 degrees? I’ve read a few posts on here from people who claim that it dropped their FC to minimum FC level or below after adding it which has me a bit worried.

 

[Newdude]

I assume you mean that I should add between 22-32

Yes. The high amount (17 oz) times 2 for 20k gallons. It's not an exact science when the parameters of the dose are so far apart.

The bottle is 32 oz, 2 oz shy of our estimated dose which probably accounts for your pool being slightly less than 20k. Close enough is close enough here.

Is it better to go with the lesser amount (22 oz) since it won’t lower the FC as much or use a higher amount since it’s been 2 weeks since doing a SLAM and my pool filled up with leaves after a storm a few days ago? Will polyquat protect my pool against algae if the FC dips down lower than minimum FC level soon after adding it and before the water temperature drops below 60 degrees? I’ve read a few posts on here from people who claim that it dropped their FC to minimum FC level or below after adding it which has me a bit worried.

All great questions and nobody knows as it's all speculation. According to the manufacturer, the PQ will outlast the FC and and help prevent algae growth. Even if the water is above 60 here and there, it's not 85 now, so there is that. But also if algecide could entirely stop algae without LC, people wouldn't be adding LC all the time, especially with how expensive it's been.