Need for SLAM?

[rjb1211]

I have had a great summer with the pool. I have kept the chlorine level "hot" (8 to 9) with the new SWG and have had zero CC.

As I think about closing the pool I was wondering if I really need to go through the SLAM process. It won't be closed until the pool water is well below 60 degrees and air temps are cool. Last year I had extremely high chlorine levels all winter making testing the pH impossible. Before someone says I don't need to test over the winter I had scale when I opened one year and had to replaster the pool. I won't let that happen again.

 

[PoolStored]

Closing an In Ground Pool

Winterizing a pool is essential for keeping your in-ground pool protected during cold-weather months. This Pool Repair guide will show you how to do it.

www.troublefreepool.com

 

[rjb1211]

Closing an In Ground Pool

Winterizing a pool is essential for keeping your in-ground pool protected during cold-weather months. This Pool Repair guide will show you how to do it.

www.troublefreepool.com

Yes, I am well aware of that article. I am questioning my need to SLAM before closing given my parameters.

 

[wireform]

Just have the FC at slam level for closing, not a very big deal that'll go a long way

 

[rjb1211]

Let me put this another way. I don't want to SLAM right before closing and go through another winter unable to read pH due to high chlorine levels. If I close with cool water and air temps and with no algae or CC what good will a SLAM do?

 

[PoolStored]

Before someone says I don't need to test over the winter I had scale when I opened one year and had to replaster the pool. I won't let that happen again.

Post a full set of results. FC, CC, pH, TA, CH, CYA.

 

[Newdude]

You need FC over the winter to be free and clear of min, the same as during the season. Once covered it will last significantly longer than during the season, but most of us don't want to possibly need to add more down the road from starting with a 6(?) FC. Especially with the equipment offline. So it's easiest to bring it to SLAM when closing late and play the odds that it'll be enough to last until the algae is long dormant. But it's also fine if you wish to manually add FC as needed and use a sump pump or such to disperse it.

Before someone says I don't need to test over the winter I had scale when I opened one year and had to replaster the pool. I won't let that happen again.

Talk to @ajw22 who realized he had similar after stopping using borates. He's going to experiment this year to see if using them again stops the issue.

 

[ajw22]

Before someone says I don't need to test over the winter I had scale when I opened one year and had to replaster the pool.

The Borate Pool Opening in Aqua Magazine discusses how borates can limit pH rise while a pool is closed for the winter. High pH while a pool is closed can cause scaling. For those that find their pools with very high pH at Spring opening borates may benefit with the pool open or closed.

Borates in pool - Further Reading

www.troublefreepool.com

 

[rjb1211]

I found the article on Borates earlier today. I am going to research that before closing.

Back to the SLAM question, last year my pool temperature was down to 52 when I did the SLAM. Several days later it had not dropped from 22. When I opened the pool in March it was still 21.

At those levels I have no idea what is going on with the pH. I don’t want to buy a probe given the issues with them.

 

[Newdude]

last year my pool temperature was down to 52 when I did the SLAM. Several days later it had not dropped from 22. When I opened the pool in March it was still 21.

That means your chosen timing for open/ close are GREAT. And you'll be golden if you can minimize the Ph rise.

Also wanted to know if the replaster was recent. I remember you upgrading the system in the spring but if that was the tail end of a full remodel, the Ph rise last winter may have been worse with new plaster.

 

[Newdude]

Also, I can assume you have a solid cover if it held FC all winter. Between what little UV makes it though my mesh, and 2 ft of rain I lose about 1/2 of mine. But I close in Nov and don't need to be at SWG slam so I aim for 14 FC. There's 6+ left at opening in April and it's plenty.

So for your original question with the rest of the info supplied, I don't see the need for you to go full slam either if you're monitoring it and can step in if needed. The more years it works, the less you'll be concerned about it making it through the winter. If you need a boost when you're already checking it, then step in.

 

[rjb1211]

Here are some more details.

I installed the pool in 1992. That was before Al Gore invented the internet so I used a pool store for info. The pool needed to be replastered in2005 because of scale.

That finish gave way and the pebble finish was done in 2017. That was due to poor prep work on the previous job not scale.

I changed from a water bag cover to a mesh safety cover in 2018. It was after the pebble finish and mesh cover that I decided to monitor the water over the winter. Any testing is done after circulating the water for a day with a submersible pump. If I add anything the water is circulated for a day or two depending on the weather. I don’t think I added anything last winter, mainly because I didn’t know what the pH was. Luckily I had no scale in the spring.

This year the closing will be around two weeks earlier than last year. I am going to pay attention to the weather as I approach the closing date. If it is going to be warm I will SLAM, if not I will skip it.

 

[Newdude]

I changed from a water bag cover to a mesh safety cover in 2018.

That's wild you kept all your FC. We get 2 or 3 ft of rain in the off season plus whatever snow melts.

How often do you drain and how much ?

This year the closing will be around two weeks earlier than last year. I am going to pay attention to the weather as I approach the closing date. If it is going to be warm I will SLAM, if not I will skip it

If you're monitoring it periodically then SLAM definitely isn't needed. That's for the folks who walk away completely so they make it up to 8 months on its own. Many don't want to circulate it and add if necessary but keeping tabs on it is great if you don't mind.

My FC was lower than i liked when I drained the second time last winter so I added 2 gallons of LC to bump it back up.

 

[rjb1211]

We had a rather dry winter last year plus I opened the pool for the equipment job before the spring rains. I don’t remember draining it at all. I probably did that twice in prior years.

That is certainly something I need to keep in mind going forward as it won’t be opened as early again.