Treating Pool In Winter To Prevent Miserable Opening Every Year

Mckinley

Member
May 4, 2015
22
Chardon, ohio
Hi Everyone,

I live in the Cleveland, Ohio area and have an inground pool. I correctly close the pool every fall and add all of the correct chemicals to get me through the winter. The pool is covered and lines are blown out and capped so I cannot run the pump till I open. Every year I open up to a green pool no matter how early I open and it's absolutely miserable to get it under control. I'm told not to add any chemicals during the winter since I can't run the pump. Is this true? Can I add anything to the water during the winter months to hopefully stop the water from turning green before I open?

Appreciate any help....thanks
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
14,854
Tucson, AZ
Do you follow the procedure in Pool School - Pool School - Closing an In Ground Pool

Do you wait until the water temperature is consistently below 60F before closing? Many people don't do this or they wait until it close to 60F and close. I imagine that, in your area, a consistent water temperature below 60F doesn't happen until late October / early November at the earliest which is usually well past the date that local pool companies will schedule closings. It's not easy to do it so late because it means fiddling with pool water when the air temps are really low and most people don't enjoy that.

Also, when you open, do you open before the water temps get to 60F?

I don't close my pool because of where I live but I can certainly say I would not own a pool if I had to go through that dance every year. You can only add chemicals to a pool if (A) that water is not frozen and (B) you have a way of circulating the chemicals. If you pour bleach or acid into a pool of cold water it is going to pool in one spot and you'll damage your liner. So adding chemicals over the winter is really not a good idea without the circulation system running to move them.
 

Mckinley

Member
May 4, 2015
22
Chardon, ohio
Thanks for responding. I follow the closing as closely as I can. I have a mesh cover and a lot of trees around the pool so I close before the leaves really start coming down. Water is usually in the low 60's when I close. I check the water during the winter and spring and it's always clear. It turns green when the temp is in the low 50's and I have no explanation for that.
 

Chemnut

In The Industry
Apr 5, 2017
231
Maine
I close my pool in the middle of September when my water is 60ish, I also use a mesh safety coverI bump up the chlorine a week before I close it. The day of closing, I put in a bottle of polquat 60 algaecide. I just now pulled the cover back and my water is crystal clear with some fine stuff on the bottom.

Bump up your chlorine, remove all leaves, add poly60 and close it. You shouldn't get green water every spring.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
14,854
Tucson, AZ
Thanks for responding. I follow the closing as closely as I can. I have a mesh cover and a lot of trees around the pool so I close before the leaves really start coming down. Water is usually in the low 60's when I close. I check the water during the winter and spring and it's always clear. It turns green when the temp is in the low 50's and I have no explanation for that.
But you said you open to a green pool every Spring? So, when you check the pool, it's not clear in the Spring....please clarify.

Here's what I think is happening - you're closing (i.e., not chemically treating) your pool while the mesh cover is on and the leaves are dropping. So basically your pool is loading up with fine organic debris (your mesh cover is only catching big stuff) and that is sitting in the water until Spring. You're also doing this while the water temperature is probably bouncing around in the low 60's. The fact is, 60F is not a magic number - algae isn't killed by cold water (just ask all the algae and plankton that grows in the waters off Antartica). All 60F means is that the algae reproduction rates are very slow. So you have water that's loaded up with organics and little or no sanitizer in the water. That is a recipe for a nice slow winter stew of algae and that is probably why you're seeing a little bit of green when the water is cold. Then, when the water starts to warm up even a smidge over 60F and, POW, the algae takes off.

Polyquat 60 is not going to help. It's an algaecide but it doesn't last the whole winter and it will dissipate. You might benefit by adding borates to your water as they are a mild algaecide and you might also benefit from treating for phosphates as the organic load is no doubt increasing your phosphate levels. Phosphates are nutrients for algae growth and, when low or no sanitizer is present, high phosphate levels make the water more conducive to algae growth. Treating for phosphates is not hard but it requires certain criteria to be met or else it's a pointless process.

But here's the real problem - your pool, with the mesh cover, is basically open to the environment all winter long and it has little or no sanitizer in it. So anything that gets in the water is going to find a happy home to grow in. I would say that, if you truly want clear water, you need to actively manage the water all through leaf fall (with the mesh cover in place) and then, when the water is finally cold enough (below 60F), you need to sanitize as prescribed in the Pool School article (SLAM plus Polyquat) and then close it with a solid cover. That way, the pool water gets little to no sunlight, it has no organic load flowing into it and the FC will hold for a long enough period of time to kill anything in it. Then, you need to open early and get the water going.

I'm sure none of that is what you wanted to hear. As I said, if I had a short swim season (less than 3 months) and had to open and close a pool every year, I would simply not own a pool, it would not be worth it in my opinion. But you do have a pool and it obviously is useful to you so, unfortunately, you have to deal more forcefully with it.

Sorry, but that's my opinion on the matter. Maybe other pool owners with a similar climate can give you better advice.
 

richierich

Bronze Supporter
Jul 12, 2013
584
Long Island, NY
I agree with most of what you said except the mesh cover part. If he closed with a high FC number his pool would still be sparkling clear. That's what I did with my intex pool the last 2 years before I got rid of it. These are the micro mesh covers that only allows rainwater to get in. Nothing else gets in except very fine silt.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
14,854
Tucson, AZ
I agree with most of what you said except the mesh cover part. If he closed with a high FC number his pool would still be sparkling clear. That's what I did with my intex pool the last 2 years before I got rid of it. These are the micro mesh covers that only allows rainwater to get in. Nothing else gets in except very fine silt.
That's fine. But if one leaves a pile of leaf litter on the mesh cover and it's allowed to stay moist, all kids of stuff can proliferate and grow. Algae, being only a few micrometers in diameter, could easily find it's way through the mesh and into the pool. My assertion is that success with mesh cover depends a lot on how actively you manage the water throughout the Fall. Again, I don't close so I don't have these issues. With that said, algae growth isn't magical or mysterious, it comes from low sanitizer levels and water that has sufficient nutrient levels in it to allow algae to reproduce. If the water starts off with a load of algae in it, it's only going to go dormant during the colder weather and then proliferate as soon as conditions are right. This is why TFP recommends managing your water until the temperatures drop to a point where reproduction rates slow down - to avoid building up an algae load. Even a winterized pool that is crystal clear upon opening probably has an imperceptible amount of algae in it; if you open the pool early enough and get sanitizer levels up, then you'll never know about it because the algae simply won't have time to reproduce and cloud the water. Opening and closing to a clear pool is all a game of timing and so my guess is the OP simply needs to manage the water chemistry for a longer period of time on either end of the season.
 

Mckinley

Member
May 4, 2015
22
Chardon, ohio
I close my pool late september, early october and the water is 60ish. I add a bottle of polyquat 60 also and bump up chlorine a week before closing. All leaves are removed and pool is brushed. Water was green upon opening and the water temp was 54. Go figure.
 

Mckinley

Member
May 4, 2015
22
Chardon, ohio
The last few winters in the NE Ohio area have been horrible for temp fluctuation. February saw 20 degrees, 2 inches of rain in one day, to 70 degrees in the same week. Then the following week back below freezing and major snow. The cover is snow covered most of the winter when the weather is normal. I have a pool that is surrounded by a lot of trees which cause me to close when the leaves really start to fall but by then the water is in the low 60s. With the winds in late fall you will get leaves that blow under the cover. I appreciate all the help. We love the pool in the summer and use it daily but the opening is so miserable with the algae that I dread this time of the year. Use nothing but bleach and the pool is trouble free in the summer. A nightmare every spring.
 

Leebo

Admin
TFP Expert
LifeTime Supporter
Jul 21, 2011
8,186
Eastern Ohio


None of us are really 100% "immune" to the green. As others have said, the last few years temps have been all over the place. A true "open early and close late" has been impossible.....unless you're willing to close in December and open in February.
 

dsmith99

Silver Supporter
Jun 18, 2016
236
SW, Iowa
We had a really mild fall so I ran my pool into the first week of November, the day I closed the water was in the upper 40's. I didn't do anything chemical wise to close, no algecide, no shock, nothing. I just maintained my 7ppm FC right up until I unhooked the pump and covered the pool.

It was a pretty mild winter, I never got my snowplow out and didn't even start the snow blower. Had some below zero temps, a few light snows but quite a few days in the 20's -30's and rain a few times. A week of warmer days in January allowed the ice on the cover to melt enough I could pump the standing water off.

Got most all the water off the cover the first of April and within a few days the sun and wind had the cover all but dry. With rain in the forecast I pulled the cover off April 11th to find the water crystal clear and 57 degrees. Ran a test and still had 3.5ppm FC and everything else was just as it was at closing. Got the pool topped off, pump connected and running, and the chlorine back to 7. Put in a pound of stabilizer to compensate for the refill and the pool is good to go, just need some warm weather now.

Easiest opening I can recall. Was my first year for this pool but there was a 27' pool when we moved here in 2002. It was all very poorly done, rusty, not level and the deck was falling apart so I removed it in 2007. It spent all of the 2006 season aqua green and cloudy despite the hundreds of dollars worth of shock and tablets ran through it.

IMG_1167.jpg
 

Swampwoman

TFP Expert
LifeTime Supporter
Apr 27, 2012
3,845
Grand Rapids, MI
McKinley, do you blow off the leaves regularly after closing?
I'm in Michigan, and until this year when I quit closing at all due to the purchase of a winter dome, I would close around Oct 23rd but then using a leaf blower etc. would continually remove the leaves from the cover so they wouldn't freeze there. My cover was solid with a mesh square, which helped, but I think the combo of TFP closing, opening in April, and making sure leaf debris did not build up on the mesh square helped me open clean each year.

Here's an example of what my pool cover looked like around Oct 25 each year ;) Yet seriously, I still opened clean!

If that doesn't work, consider getting a solid cover. I know mesh is lighter and all the rage, but it sounds like a solid cover would really help in your case.

image.jpg
 

Mckinley

Member
May 4, 2015
22
Chardon, ohio
Looks like my pool in October with the leaves. As tight as you can get the cover with the heavy winds you do get leaves and worms in the pool. I do blow the leaves off every chance I get. Thinking about running an external pump with hoses in the pool in the winter to circulate the water so I can add a gallon or so of chlorine on warmer spring days near the end of winter. Anyone ever tried that?
 

Chemnut

In The Industry
Apr 5, 2017
231
Maine
If you read up on polyquat and raise your chlorine levels to shock well before closing it will in fact help a lot, once that chlorine comes down you can then add the poly60. Lots of nay Sayers but the fact remains it will slow down an algae growth. It won't eliminate it. If you don't raise chlorine levels to shock values before closing are you truly sure nothing was lurking.

I suspect you had algae lurking. Chlorine dropped below target values and voila. Even had you added poly in that situation you would still have algae, just to a lesser extent.
 

Swampwoman

TFP Expert
LifeTime Supporter
Apr 27, 2012
3,845
Grand Rapids, MI
McKinley, I haven't gotten leaves in, but the odd worm finds its way...I do keep the straps tight.
For about 5 years running I'd open to a FC of about 4...my FC may have stayed higher due to mostly solid and ergo dark cover.
 

Andrew Howard

Well-known member
Dec 21, 2015
122
Newington, Connecticut
Hey McKinley

I usually test my water in February to see what's left for chlorine levels. I use a skinny snow stake to push my test bottle to the bottom to get an average water sample. I bring the sample inside to warm up before testing. If low I use a submersible pump with a 90 degree elbow to get the water moving, usually takes an hour or two. Once water is moving you can add bleach and let pump run for couple of hours to mix. My water is about 50 degrees to 55 degrees and will be opening this week.
 

Swampwoman

TFP Expert
LifeTime Supporter
Apr 27, 2012
3,845
Grand Rapids, MI
McKinley, there are two more options that might help, together with a later closing:

1. Soft Oct semi closing...use a leaf net cover over the pool, secured to your same anchors as your mesh cover. Walk the leaves off when you add FC ;) (I did this last Oct while awaiting my done, which nstalled in Nov.)

Follow with "hard" plumbing close in November, swap to mesh cover, only let FC slam level drop for a day or two before hard close so that your FC is elevated, but not at slam level...open before water hits 60.

2. Same as above, but use your mesh cover for the soft close, with periodic peel back and FC addition until a hard plumbing close in November.

While you can always add chlorine and brush to circulate, its a risk to vinyl liner because chlorine is heavier than water and can pool on bottom...with a cover mostly on and no pump running, I feel its tough to know if you've manually circulated enough to avoid problems...
 

bmoreswim

Mod Squad
Gold Supporter
Platinum Supporter
LifeTime Supporter
Jul 16, 2012
4,540
Central MD
I'm 4 for 4 opening to a clear pool with a mesh cover in central MD. I feel you can be assured of it every year if you monitor your pool with some regularity during the high risk times after closing and before opening during March through November. The only (almost completely) safe months at my latitude and north are Dec-Feb. In a few years that may no longer be the case.

Another trick is to not let the water rise to come in contact with the mesh cover (or let the cover get so loose that it touches the water). Without snow of course. The reason this is important is because the micro-climate of a colored cover, with a skim of water on it during a sunny day with no wind is HIGHLY conducive for algae growth, which then migrates in to the pool.
 

skimmerswimmer

Well-known member
Jul 30, 2013
254
Long Island, NY
1. Close late when water temp is below 60
2. Raise FCL to mid teens and fully clean pool prior to closing
3. Add polyquat 60
4. String 2 floating chlorinators with 4 pucks each across pool so they stay centered during the winter.

Open to clear pool every year.
 
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