When to open? (Southwestern Ontario, Canada)

G-Note

Member
Mar 27, 2018
8
London, Ontario Canada
Hey everyone,

I am noticing several pools in my area are now open. I was planning to open the first week of May but now I'm second guessing that.

We have an inground vinyl liner pool with a black mesh safety cover. Peeking through the cover the water is clear. The next couple of weeks will have daytime temperatures of 14C-20C (55-70F)

Should I open now or stick with early May?
 

CrystalRiver

Well-known member
Jun 19, 2020
648
Massachusetts
You want to open before your water hits 60 degrees. Below 60, algae growth is super slow, almost negligible. As it warms up, algae growth speeds up. Opening around 60 degrees should have you opening before it turns into a swamp.

I tied a thermometer to a pool noodle and threw that in on top of the cover. That way I can keep an eye on water temperatures. Daytime highs and how much sun is on the pool matter, but so does the overnight lows. Instead of me trying to read the forecast and guess what the water is going to do, I can just go read the thermometer.
 

Newdude

Gold Supporter
TFP Guide
Jun 16, 2019
8,829
NY
The main reason to cover is to stop the fall debris from falling and the main reason to winterize is to protect against freezing. Once they both pass, there is no harm in opening and the early season treating of the water is much less so you won’t need to be adding chlorine every day. It might not even be weekly for you yet.

If you choose to leave it covered wait out pollen season, the air temps will be too warm and you’ll be begging for swamp problems. Pollen is easy to clear with only filtering and run time needed. (Albeit a slow week or two of filtering) Swamps are a lot more work *and* filtering / run time.
 

Pool_Medic

In The Industry
Apr 1, 2018
1,522
Bangor Maine
That black safety is going to accelerate the water temps rising. I have handshake agreements with all my customers that I open their pools once the ice is gone. Several I open and leave their safety covers on until the maple buds are done dropping.
 

Newdude

Gold Supporter
TFP Guide
Jun 16, 2019
8,829
NY
You can also get the equipment running and leave the cover on. You can test as needed from the skimmer and just pop a corner to make any corrections. (Preferably in front of a return for mixing purposes) It will ensure the water stays clear and when you are ready, all you have to do is pop the cover and you’re open.
 

Brianf60

Well-known member
May 18, 2017
181
Bradford ontario
I opened yesterday. Water temp is 46f.water is crystal clear after vacuuming twice. Close late and open early and life is easier. My wife made a good point too. It's much nicer to look at an open pool than a closed one...
 
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Newdude

Gold Supporter
TFP Guide
Jun 16, 2019
8,829
NY
My wife made a good point too. It's much nicer to look at an open pool than a closed one
I opened/closer every year for aesthetics alone when it was way cooler than anyone wanted to swim. Unbeknownst to me at the time I was saving myself the swamp that all my hardcore Memorial Day to Labor Day friends had.

Sooooooo many people (where we have actual seasons) choose those days regardless if the weather is 50 or 90.
 
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