Algaecide in winter

[xDom]

I keep hearing advice about winterising my pool, about how I need to use an algaecide.

Why can’t I just keep all the normal chemical levels the same as in summer?
If my FC to CYA ratio in summer was enough to prevent algae then surely that same ratio will prevent it in winter?

I don’t understand it when people have to address a green pool at the beginning of summer? Isn’t it more efficient to just keep everything normal throughout winter ( with a modified pump schedule ) ?

 

[dfwnoob]

I'm not sure where you live in Australia, but if your weather is anything like it is here in Texas, there's really no need to close or winterize a pool. Mine is open 365 days of the year. Chlorine demand drops off so hard in colder weather anyway, so it's a breeze to take care of.

Most people closing/winterizing live in the more northern latitudes.

 

[xDom]

I'm not sure where you live in Australia, but if your weather is anything like it is here in Texas, there's really no need to close or winterize a pool. Mine is open 365 days of the year. Chlorine demand drops off so hard in colder weather anyway, so it's a breeze to take care of.

Most people closing/winterizing live in the more northern latitudes.

my water temp will get down to about 5 degrees C here ( 41 F )
If anything though, the colder the temp the less chance of algae anyway?
What am I missing with the “ winterising “ process?
Is it to do with freezing weather?

 

[IceShadow]

my water temp will get down to about 5 degrees C here ( 41 F )
If anything though, the colder the temp the less chance of algae anyway?
What am I missing with the “ winterising “ process?
Is it to do with freezing weather?

Pretty much. We have to drain our pipes here in Wisconsin because the water will freeze and break the pipes if we don't. We put a safety cover over the pool as well to make sure no one falls in among the snow / etc. No moving water = no adding chlorine. (Though some people rig up ways to do it anyhow.)

 

[xDom]

Pretty much. We have to drain our pipes here in Wisconsin because the water will freeze and break the pipes if we don't. We put a safety cover over the pool as well to make sure no one falls in among the snow / etc. No moving water = no adding chlorine. (Though some people rig up ways to do it anyhow.)

Oh ok! So there’s a bit involved. How far below freezing do you get? Is the pool frozen solid?

 

[IceShadow]

Oh ok! So there’s a bit involved. How far below freezing do you get? Is the pool frozen solid?

The top of it is. I never tried to drill through the ice to see how far down it freezes or anything, especially since the mesh cover is on. So the water goes down to 0 C (32 F) and sits there (as reported by my remote thermometer).

Our average temp in winter is 16 F (-8 C) and our record low here is -55 F (-48 C). It gets pretty cold. The pipes are the main concern - if there's water in them that's not moving, it can freeze, and if it gets REALLY cold it'll start even with water moving. Frozen pipes = breaking pipes due to water expansion when freezing.

 

[mgtfp]

I'm in Melbourne, water temp goes down to about to 7°C at the height of winter. Pool stays open, SWG runs all year. My pool is fully shaded in winter, and I only need to add about 0.25ppm of FC per day. I allow CYA to drop to about 30-40 over winter (due to pumping rain overflow to waste), before I bother to start adding CYA again (I don't like to let it drop below 30, because the test doesn't work below 30, and I prefer to know where I am). But I don't increase CYA back to 80 before December (towards end of Oct / start of Nov I aim for 60-70, and then up to 80 in December, that usually gets me through the season without having to add more). I maintain 10ish FC over winter, that allows enough buffer for weekly or even fortnightly testing without surprises once I understood how my pool behaves, and I don't get swamped when spring comes and the SWG needs ramping up again.

Most Aussie SWG's are designed to run through Aussie winters. They run at higher salt levels compared to the US models, and rather than controlling chlorine output via a duty cycle (switching multiple times per hour between 100% output and 0%) as common in the US, they adjust the voltage to regulate the current (which is proportional to the chlorine output). That allows them to compensate the reduced conductivity of the water at lower temperatures by running at higher voltages. They might fail to run at 100% in winter, but that's hardly required anyway.

Where in Australia are you? I doubt that you need to worry about winterising. Just find a "winter mode'" that works for you.

 

[xDom]

I'm in Melbourne, water temp goes down to about to 7°C at the height of winter. Pool stays open, SWG runs all year. My pool is fully shaded in winter, and I only need to add about 0.25ppm of FC per day. I allow CYA to drop to about 30-40 over winter (due to pumping rain overflow to waste), before I bother to start adding CYA again (I don't like to let it drop below 30, because the test doesn't work below 30, and I prefer to know where I am). But I don't increase CYA back to 80 before December (towards end of Oct / start of Nov I aim for 60-70, and then up to 80 in December, that usually gets me through the season without having to add more). I maintain 10ish FC over winter, that allows enough buffer for weekly or even fortnightly testing without surprises once I understood how my pool behaves, and I don't get swamped when spring comes and the SWG needs ramping up again.

Most Aussie SWG's are designed to run through Aussie winters. They run at higher salt levels compared to the US models, and rather than controlling chlorine output via a duty cycle (switching multiple times per hour between 100% output and 0%) as common in the US, they adjust the voltage to regulate the current (which is proportional to the chlorine output). That allows them to compensate the reduced conductivity of the water at lower temperatures by running at higher voltages. They might fail to run at 100% in winter, but that's hardly required anyway.

Where in Australia are you? I doubt that you need to worry about winterising. Just find a "winter mode'" that works for you.

I’m just up the road from you, Bendigo.

I have this situation with my SWG in that it’s way oversized for my pool. Originally I was using an ORP probe but I found it too erratic.
Problem is that if I leave it on a setting, even the lowest, it overdoses the pool.

I’ve disabled it and now use the chlorine setting on my app to manually control the chlorine level.
I’ve been testing every few days and when my FC drops to about 2.6 I run the SWG for a few hours at mid power, this brings it up to about 3.5.
That’s not a bad idea that you mentioned, taking the FC up to 10, checking it a week or so later.

 

[AUSpool]

I’m just up the road from you, Bendigo.

I have this situation with my SWG in that it’s way oversized for my pool. Originally I was using an ORP probe but I found it too erratic.
Problem is that if I leave it on a setting, even the lowest, it overdoses the pool.

I’ve disabled it and now use the chlorine setting on my app to manually control the chlorine level.
I’ve been testing every few days and when my FC drops to about 2.6 I run the SWG for a few hours at mid power, this brings it up to about 3.5.
That’s not a bad idea that you mentioned, taking the FC up to 10, checking it a week or so later.

I think it was a good choice to turn your ORP off. They are just too much bother for a domestic pool with CyA and I would never be without CyA.

Its best to keep your SWG output balanced to your FC demand. Instead of using it to play catch up just turn it up a little and bring your FC up to your target level with a manual dose of pool chlorine.

I manage my pool the same as mgtfp described. The big suppliers via the pool shops have jumped on this winterising thing to sell us something we just don’t need. There may be a hand full of pools in the high country that may need it but those people know what they need to do already.