Closing at SLAM level for the first time

[al27]

I did a soft close earlier this month and my pool is going to be winterized by a local pool guy on Monday so I don’t have to worry about any freeze damage when freezing overnight temperatures start occurring in a few days. We normally add polyquat at closing but I decided to close at SLAM level instead this year since we haven’t had much luck in the past with the polyquat. I have never closed at SLAM level before so I have a few questions:

1. How long do we need to run the pump after getting FC up to SLAM level so I can make sure the chlorine gets mixed in real good before it is winterized? FC is at half SLAM level now so I will have to add a gallon of 12.5 percent chlorine before closing to get it up to SLAM level. I’d like to wait until the morning of closing to add the chlorine unless the pump needs to run for longer than an hour or two because heavy rain is expected all day tomorrow.

2. Since the water temperature is 65 degrees now and our pool has a mesh cover that doesn’t block out all of the sun, should I test the chlorine in a few weeks to make sure we haven’t lost too much chlorine and add more chlorine if needed? If so, how do I get an accurate chlorine reading since the pump has been off and how do I get the chlorine mixed in well enough to prevent algae?

3. Could the heavily chlorinated water damage my mesh cover or gelcoat, and could it damage my sump pump or grass when draining water out after closing and throughout the winter? Would watering the lawn after adding the chlorine help prevent any damage to my grass from the heavily chlorinated water?

 

[HermanTX]

1. How long do we need to run the pump after getting FC up to SLAM level so I can make sure the chlorine gets mixed in real good before it is winterized? FC is at half SLAM level now so I will have to add a gallon of 12.5 percent chlorine before closing to get it up to SLAM level. I’d like to wait until the morning of closing to add the chlorine unless the pump needs to run for longer than an hour or two because heavy rain is expected all day tomorrow.

Be best to check your CYA again before adding LC. Also, might want to let your pool sample warm up a little before testing CYA.

Suggest your run (1800 to 2200rpm) your pump 30 minutes after adding LC, then test to verify FC level. Add more LC if needed to get to SLAM.
Run pump for another 30-45 minutes after your test of FC if you need to add more LC.

2. Since the water temperature is 65 degrees now and our pool has a mesh cover that doesn’t block out all of the sun, should I test the chlorine in a few weeks to make sure we haven’t lost too much chlorine and add more chlorine if needed? If so, how do I get an accurate chlorine reading since the pump has been off and how do I get the chlorine mixed in well enough to protect my pool from algae?

Once the water is mixed it will stay mixed.

3. Since I will have to drain a lot of heavily chlorinated water out of our pool at closing and at several times throughout the winter, will the high chlorine levels be hard on my sump pump and could it kill the grass? Would watering the lawn heavily after adding the chlorine be sufficient to prevent the heavily chlorinated water from killing the grass?

Can you divert your sump pump output to a driveway or a drain (if the city allows that)?

Calling @Newdude for additional input.

 

[Newdude]

How long do we need to run the pump after getting FC up to SLAM level so I can make sure the chlorine gets mixed in real good before it is winterized?

The same as always. 15 mins if the circulation is good. 30 mins if not, or just to be absoooooooolutely sure. Plus, when you turn it off it keeps stirring around for several more minutes. Lol.

should I test the chlorine in a few weeks to make sure we haven’t lost too much chlorine and add more chlorine if needed?

It cannot hurt and can only help. I wait until I'm draining because it doesn't take long to fill back up. That 0 FC rain water sitting on top is the algae maker IMO.

After I drain (trying to mostly get top water) I now drop the submersible to the bottom and move the hose to the top left/center/right for 20 mins each to stir it back up. At that point, you can grab a sample and test/add if needed. Brush the floor in that area well, you can get quite far with only a small window open up top.

Could the heavily chlorinated water damage my mesh cover or gelcoat,

It's not heavily chlorinated. Full stop. Slam FC, buffered by the CYA, has a lower available HOCL content than tap water. (That's the 'harsh' part).

and could it damage my sump pump or grass when draining water out after closing and throughout the winter?

Same answer as above. If you'd let it sit/soak in tap water, pool water will do no worse.

I do believe there are some places you can drown the grass, but you get plenty of rain so it should be used to getting soaked.

There's no reason to soak the grass afterwards, but it wouldn't hurt if you needed to for you.

 

[al27]

The same as always. 15 mins if the circulation is good. 30 mins if not, or just to be absoooooooolutely sure. Plus, when you turn it off it keeps stirring around for several more minutes. Lol.

It cannot hurt and can only help. I wait until I'm draining because it doesn't take long to fill back up. That 0 FC rain water sitting on top is the algae maker IMO.

After I drain (trying to mostly get top water) I now drop the submersible to the bottom and move the hose to the top left/center/right for 20 mins each to stir it back up. At that point, you can grab a sample and test/add if needed. Brush the floor in that area well, you can get quite far with only a small window open up top.

It's not heavily chlorinated. Full stop. Slam FC, buffered by the CYA, has a lower available HOCL content than tap water. (That's the 'harsh' part).

Same answer as above. If you'd let it sit/soak in tap water, pool water will do no worse.

I do believe there are some places you can drown the grass, but you get plenty of rain so it should be used to getting soaked.

There's no reason to soak the grass afterwards, but it wouldn't hurt if you needed to for you.

Thanks for the advice. How do you get mostly top rain water when draining so you aren’t draining chlorine out and you can get an accurate chlorine reading? I put my sump pump on the floor of the shallow end and I let it keep draining until the steps aren’t covered anymore with water, which brings the water level slightly below the bottom of the skimmer mouth. I have to do this every 6 weeks or so to keep the water level below the tiles all winter. Since those steps weren’t covered with water after closing or draining water out the last time, I assumed that I was mainly draining rain water out by doing it that way but maybe I’m wrong about this. I have access issues behind the deep end because of landscaping/trees so I couldn’t add chlorine in that area with a sump pump and brush afterwards very easily because my pool pole hits the landscaping behind the pool. I avoid adding any chemicals to my pool that need to be broadcasted in the deep end and brushed in for that reason. If the sump pump would need to be put in the deep end to mix up the chlorine and it needs to be brushed in afterwards, I’m not sure I could do it. Could I just pour some chlorine in the deep end and not stir it up with a sump pump or would that not help and could potentially leave bleach stains in my gelcoat? I have a friend with a fiberglass pool that dumps a gallon of chlorine in her pool every time she drains starting in late February and claims that she always opens to a clear pool and has no issues but she doesn’t get a lot of leaves in her pool like I do. We always end up with a lot of leaves in our pool because we have so many close trees so the organic load makes it harder to keep the pool algae free. If adding chlorine every time I drain water out might help, I’d be willing to do it.

 

[Newdude]

How do you get mostly top rain water when draining so you aren’t draining chlorine out and you can get an accurate chlorine reading?

I don't want to retain chlorine. I want to retain my salt, CYA and CH, because of the stratified dilution I proved last winter. I took samples and salt and FC were 0 at the surface, very low at 2 ft down and exactly like I left them at 7.5 feet.

Replacing the chlorine is cheap. 34k gallons worth of CYA, salt and CH on the other hand is hundreds of dollars. So to save those I will try to pump the rain water from the top. I will have to tie/hang the pump off a chair or something so it's high in the water. 2 chairs, a 2x4 and some rope in a corner maybe. I dunno. I'll just Macguyver something up that day. Lol.

Could I just pour some chlorine in the deep end and not stir it up with a sump pump or would that not help and could potentially leave bleach stains in my gelcoat?

Liquid chlorine is heavier than water and may puddle up on the floor. Especially when you aren't adding it into a running return. So it needs to be brushed well, and the submersible is already all set up at that point so it'll be easy to mix for an hour.

Pour, brush well, and walk away with the pump stirring it up for a while. That'll be plenty good enough without too much trouble.

If adding chlorine every time I drain water out might help, I’d be willing to do it.

Mix after draining and test. If you alrwady have (some of) it open to drain, you are only going to help yourself by testing and possibly adding.