Pool Covers & Evaporation

Love them or hate them, there’s no denying that a pool cover can save massive amounts of water.

Just how much varies depending on a number of factors (such as the surface area of the pool, the amount of wind, shade, water/air temperature). Anywhere between 2mm and 10mm of water every day is seen as an acceptable water loss – but this all adds up – and without rain or top ups, a pool can easily lose its entire volume of water – every year!

The single most effective thing a pool owner can do to save water is to buy (and use) a pool cover. To be honest, it doesn’t even have to be a proper pool cover – any sort of covering will help prevent evaporation – it’s just that a pool cover will be more effective, will last longer, and will be easier to use than say – cling wrap or builders plastic.

So how does it work? It’s all about evaporation. Evaporation is what happens when water turns into gas (such as steam, when you boil the kettle). Obviously your pool is not boiling like a kettle, but the theory is the same. When the water inside your pool is warmer than the air around it, evaporation will occur.  Without a cover, that water vapour will release back into the atmosphere – but with a pool cover in place, it can’t escape, and stays in your pool, where it belongs.

ABGAL Oasis Solar Pool Covers have been independently tested and proven to stop up to 99.84% of evaporation. They are Climate Care Certified, Smart Approved WaterMark Licensed, and Water Wise accredited, complying with water saving standards across all drought declared Australian states and territories.

Water Loss. Is it evaporation or a leak?

If you’re noticing your water level dropping faster than usual, it’s a good idea to check if its due to evaporation or a leak.

The first thing you should do is what they call a ‘’Bucket Test”.

How to do the Bucket Test:

  1. Fill a bucket with pool water, about 3cm from the top.
  2. Put the bucket on the first step of your pool.
  3. Turn off your pool pump.
  4. Using a permanent marker or pieces of waterproof tape, mark the water levels both inside and outside of the bucket.
  5. Turn your pool pump back on.
  6. Wait 24 hours, and compare the water levels.
How to do the 'bucket test'.

If the water level on the outside of the bucket has gone down more than the level on the inside, it’s likely you have a leak.

If the water level on the inside of the bucket has gone down by around the same rate, then your water loss is caused by evaporation. This can be resolved by using a pool cover.

True or False? Uncovering the myths about pool covers…

1. “You don’t need a pool cover with a heated pool.”
A. False. Yes, you do. More than one third of the heat you put into your pool can be wasted if you don’t cover it up. We as a society can’t afford to waste that much energy these days, particularly if your pool is heated using fossil fuels like electricity or gas.

2. “Pool covers don’t work that well anyway” 
A. False. Yes, they do. It is a scientific fact that a waterproof cover stops evaporation and reduces chemical usage.

3. Just use “floating rings” or this “new miracle chemical” that you cannot see, but somehow magically eliminates evaporation from your pool.
A. False, false, false. The simple fact is, if the cover is fully waterproof, it will stop nearly 100% of water evaporating out of your pool. Floating rings and invisible chemicals just don’t do the same job. Don’t be fooled by bogus claims. If it seems too good to be true, it very often is.

4. Do I really need a pool cover in the winter time?
A. True if you want to save water and pool chemicals. With a cover you can reduce the pool filter running cycle to save electricity too. Otherwise you will still spend the same on electricity running the filter and cleaning time keeping leaves and debris out of the pool.

5. Pool covers look ugly, don’t they?
A. False. Not at all, a properly fitting and maintained pool cover will complement any pool surround.

6. Pool Covers really save a lot of chemicals?
A. True. By keeping the Sun off the pool water and reducing the light entering the pool or sealing the top of the pool, they substantially reduce the chemicals needed. A pool covered with a floating cover will use around 2/3 less chlorine.

7. I have read that some Pool Covers save over 99% evaporation?
A. True. A Pool Cover made from a fully waterproof fabric (like a floating bubble cover) will stop almost 100% of vapour transferring through the fabric.

 

Fact #2: Pool covers save water – but how much?

One of the questions I am often asked is, “How much water does a pool cover save”? We all know that pool covers save water by virtually eliminating evaporation when they’re on the pool, but how much evaporation does your pool have? It’s a valid question, and the answers can vary quite dramatically, depending on several different factors.

It would be perfectly normal for an ‘average’ sized pool to lose anywhere between 2mm and 10mm of water to evaporation every day.  Location, wind speed, humidity, shade, sunlight, air temperature and water temperature all have an impact on evaporation rates, and so does the size of your pool, so there really is no ‘average’ answer.

If you’re really keen, you can look at statistical averages on the government weather bureau website (BOM) to see rates of evaporation in your area, and then make some sort of calculation from there. It’s a complicated process though – I’ve been through the exercise with my own pool and estimate that without a cover, I’d experience evaporative water loss of over 73,000 litres per year! Isn’t that a staggering amount?
This means it’s really easy to justify why all pool owners should use a pool cover and just how much precious water they will save. to see how much we can contribute to sustainable water usage for Australia’s future, today!