End of swimming season coming.. Winter close process - South Australia - no freeze climate. Inground. Plaster

Hi all!

A last hot streak here - over 40C our hottest Autumn day on record! - but I imagine I'll only get another couple of weeks of swimming now.

I'm hoping for some local help or help from US peeps who might still monitor this forum in your off season and that might live in a similar climate to where I am. I have done a forum search but it didn't help me with the specifics I was after.. and most of it US based and talking about antifreeze!

I've only been TFP-ing for 6 weeks - previously ozone. Crystal clear for 6 weeks... Thanks TFP! CC 0 and all is well.

My winter process for ozone was to just run the pump 1 hour every day. I have a pretty cool winter cover that keeps everything out except some water so all I have to do is drain some water if it gets too high.

I'm happy to run it daily for an hour still and not do the "winterisation" process that the majority of TFP-ers seem to do.. the equipment seems happy with this as I have done it for the 3 years we've been at this house.

In Adelaide we have low humidity and lowest winter temp is maybe 2 C and that's for just a couple of nights here and there. Last year I think the winter pool temp sat around 11 or 12 C.

So should I just make my levels nice (including a partial drain - enough and refill to get my CYA nice and low - 20? so that I don't need too much chlorine) then check levels every week or so (?) and keep it above minimum recommended FC level?

I'm open to other processes, just working it all out. What do you think?
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Costas > DownUnder

Bronze Supporter
Dec 17, 2017
Adelaide | Australia
Hi there ACC,

I'm also located in Adelaide but have only had my pool since April last year however I have been using TFP method since day 1.

I would not worry about draining to reduce CYA (unless it is at a silly high level) as over winter your chlorine consumption will reduce drastically due to much less UV and the colder water temp (less 'bugs' will grow).

One thing to really watch out for during cold water temps (esp for your plaster surface) is the CSI value. It is all to easy to have CSI drop to quite negative values over winter simply due to the temp drop.

Allow your PH to rise up to above 7.6 as well as keeping your TA and CH values in check so that you don't drop say below -0.3 CSI. If TA and CH are at the lower end and with a mid to low PH, it is all too easy to have CSI drop way below -0.6 which will make the water aggressive as far as plaster is concerned (this will damage your plaster surface over time).

I religiously kept an accurate log of my parameters over last winter and my water temp never really dropped below 10C (I don't live up in the hills). So factor in say 10C worst case for water temp and plug in some typical values in the PoolMath calc to see what you require to keep CSI in check.

Good thing is that our water will never freeze over - so no need for antifreeze and no real need for 'winterisation' of the pool.
Thanks heaps for your reply Costas!

The CYA is silly high at the mo.. I was using Tri tabs for about 4 weeks and it was happily sitting at 30, I was doing levels every 4 days with no massive changes then BAM, life got busy and it blew out to a 6 day gap between doing levels and it had jumped to 80! I knew it would go up but the jump in 6 days really threw me! It was a bit odd tbh. So I'm now on liquid chlor, and checking levels 24-36 hourly and only saving tabs for trips away.

Ahh... interesting to hear about the CSI, cheers for that. It's really high at the moment - just over the highest "recommended" level so it will probs be ok but I'll certainly plonk some numbers in Pool Math and suss it out just to see.

pH is 7.6 at the mo and TA is 100 so I'll see how they look once the temp is lowered.

Love that we never have to worry about freezing, what a stress that would add to the pool regime!

Thanks again 😊
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In The Industry
Apr 30, 2018
Toronto, Ontario, Canada
With freezing temperatures, it's -12C here today, you generally close the pool, and that means draining half the water, and then blowing out the lines with air, then covering the whole thing with a winter cover. I can't even see the pool now, there is just a slight depression in the snow. The big melt is supposed to start on the weekend. We typically open the pool after Victoria Day. and close it after labour day. What would be cool is a cover where you could put plywood around the outside, then turn the pool into a skating rink for the winter....