Summer in Aotearoa is when our pools work the hardest. Long days poolside, kids jumping in and out, friends dropping by, neighbours popping over, visitors staying late, and sometimes even the dog getting a swim if they are lucky. It is the season when a pool becomes the centre of outdoor living.
It is also the season when we see the most confusion about pool covers.
Many pool owners assume that if they keep the cover on, the pool will stay cleaner, warmer, and easier to manage. While that can be partly true in the right conditions, it is not the full story. In summer, using your pool cover the wrong way can actually make the water harder to look after, especially after heavy use.
A pool cover is a brilliant tool, but it needs to be used properly. Here is our straight-up guide to getting the best from your cover over summer, keeping your water fresher, your heat in place, and your pool easier to maintain.
FIRST THINGS FIRST – POOL COVERS ARE FOR HEAT RETENTION, NOT DEBRIS CONTROL
The biggest misconception we see is that pool covers are designed to keep debris out of the pool.
They are not.
A standard thermal or solar pool cover is mainly designed to:
- Hold heat in the water
- Reduce overnight heat loss
- Limit evaporation
- Lower heating costs
- Reduce water loss
- Help the pool warm more efficiently
Yes, a cover can reduce some debris entering the water. It may stop larger leaves, insects, and loose garden matter from dropping directly into the pool. However, it does not create a perfect seal. Fine debris, dust, pollen, sunscreen residue, insects, and organic matter can still make their way into the water.
Leaves and debris will also sit on top of the cover. When the cover is rolled off, some of that material can fall into the pool if it has not been cleared first. This is why a pool cover should never be treated as a replacement for regular cleaning.
Even with a cover, your pool still needs:
- Proper filtration
- Good circulation
- Regular brushing
- Vacuuming or robotic cleaning
- Skimmer basket checks
- Water testing and balancing
- Occasional cleaning of the cover itself
A cover is part of the pool care system. It is not the whole system.
WHY LEAVING THE COVER OFF HELPS IN SUMMER
It makes sense that many people think leaving the cover on during summer will help keep the pool cleaner. After all, if the water is covered, surely less can get in.
The problem is that summer pools need to breathe.
When a pool is being used heavily, the water collects more than just leaves and visible debris. Every swimmer introduces contaminants into the pool, even when they are clean. These can include sweat, body oils, sunscreen, cosmetics, hair products, skin cells, and other organic matter.
Chlorine works hard to break these contaminants down and keep the water safe. However, when the cover stays on for long periods, the by-products of that process can become trapped at the water surface. This can lead to water that smells strong, feels stale, looks dull, or becomes harder to balance.
During summer, especially after busy swimming days, airflow and sunlight are important parts of keeping the water fresh.
The Truth About That Strong “Chlorine Smell”
One of the most common things pool owners notice after a busy day is a strong chlorine smell. Many people assume this means there is too much chlorine in the pool.
In reality, a clean and well-balanced pool should have very little smell.
That sharp “chlorine smell” is usually caused by chloramines. These form when chlorine reacts with contaminants in the water. Once chlorine binds with these contaminants, it becomes combined chlorine. That means it is no longer working as freely or effectively to sanitise the pool.
Chloramines can form when chlorine reacts with things such as:
- Sweat
- Sunscreen
- Body oils
- Makeup
- Hair products
- Skin cells
- Dirt
- Urine
When chloramines build up, the water can start to smell harsh. Some swimmers may also notice eye irritation, skin discomfort, or water that feels less pleasant than usual.
This is why a strong chlorine smell should not be ignored. It does not automatically mean the pool is unsafe, but it does mean the water needs attention.
Why Sunlight and Fresh Air Matter
Sunlight and fresh air help the pool recover after heavy use.
UV exposure from the sun helps break down chloramines at the water surface. Fresh air allows those gases to escape rather than becoming trapped under the cover. When the pool cover is left on all day, especially after swimming, chloramines have nowhere to go. They build up under the cover and can make the water smell stronger when the cover is removed.
This is why the summer rule is simple:
Cover off during the day. Cover on at night.
During the day, let the pool breathe. Let sunlight and airflow help clear out chloramines and keep the water fresh. At night, put the cover back on to hold in heat and reduce evaporation.
This approach gives you the best of both worlds. You support healthier water during the day and protect your heat overnight.
When You Should Definitely Take the Cover Off
There are certain times when removing the cover is especially important.
After a big swimming day, the pool needs ventilation. If the kids have been in and out all afternoon, guests have been swimming, sunscreen has been applied, or the pool has had more use than normal, take the cover off and leave the water exposed for a while.
You should also remove the cover if the water smells strong, looks dull, feels slippery, or seems cloudy. These can all be signs that the pool needs better circulation, sunlight, fresh air, or a water balance check.
It is also a good idea to keep the cover off while the pool is being treated, depending on the product being used. Some pool treatments need circulation and ventilation to work properly. Your pool care team can advise what is best for your specific system.
Why You Should Still Cover the Pool at Night
While the cover should come off during the day in summer, it should usually go back on at night, especially if the pool is heated.
Night-time is when pools lose a lot of heat. Air temperatures drop, wind moves across the water, and heat escapes from the pool surface. A cover acts like a blanket, helping to hold that warmth in the water.
This is particularly important for heated pools. If you leave a heated pool uncovered overnight, your heating system has to work much harder to bring the water back up to temperature the next day. That means higher energy use and higher running costs.
A cover also helps reduce evaporation. During warm, dry, or windy weather, uncovered pools can lose a surprising amount of water. Less evaporation means less topping up, more stable water chemistry, and better overall efficiency.
Pool Covers and Chlorine Use
One thing to understand during summer is that chlorine demand changes depending on weather, pool use, and whether the cover is on or off.
When the cover is off during the day, UV exposure will break down chlorine faster. This is normal. It is not a sign that something is wrong. It simply means the pool is being exposed to sun, swimmers, and outdoor conditions.
When the cover is on for long periods, chlorine may be protected from UV, but contaminants and chloramines can become trapped. That is why the goal is not to keep the cover on constantly. The goal is balance.
In summer, you may need to test your water more often, especially during periods of heavy swimming, high heat, or long sunny days. Your pool may need more regular adjustment than it does in cooler months.
Summer Pool Cover Dos
Do let your pool ventilate during the day
Fresh air and sunlight help keep the water healthier, especially after heavy use. If the pool has been busy, leave the cover off so chloramines can escape and the water can recover.
Do cover the pool again at night
This is one of the best ways to hold heat in the water, reduce evaporation, and lower heating costs. For heated pools, night-time cover use makes a noticeable difference.
Do run your robot or vacuum regularly
A cover does not keep the pool debris-free. Fine debris, dust, and organic matter still enter the water. Your robot, vacuum, and filtration system all still need to do their job.
Do brush the pool
Brushing helps move fine particles into circulation so the filtration system can collect them. It also helps prevent algae from taking hold in corners, steps, and low-flow areas.
Do clear debris from the cover
Leaves and dirt sitting on top of the cover can fall into the pool when the cover is rolled back. Clearing the cover before removing it helps reduce mess.
Do clean the cover occasionally
A dirty cover can drip grime, algae, and residue back into the pool. Giving it a proper clean from time to time helps protect both the cover and the water.
Do check your water more often in summer
Higher temperatures, stronger sun, and more swimmers all put extra pressure on water chemistry. Regular testing helps prevent small issues from becoming bigger ones.
Summer Pool Cover Don’ts
Don’t leave the cover on for several days at a time
This can trap chloramines, reduce ventilation, and leave the water smelling stale or looking cloudy. Pools need airflow, especially in warm weather.
Don’t assume a cover means less maintenance
The pool still needs circulation, filtration, brushing, cleaning, and balancing. A cover reduces some workload, but it does not remove the need for proper care.
Don’t ignore a strong chlorine smell
A strong smell usually means chloramines are present. Start by removing the cover, letting the pool ventilate, and running the circulation system. If the smell continues, the water may need testing and adjustment.
Don’t forget your pump run-times
Good circulation is essential in hot weather. If the pump is not running long enough, chemicals may not distribute properly and debris may not be filtered effectively.
Don’t roll a dirty cover straight into storage
If the cover is covered in leaves, dirt, or standing water, clean it before rolling it away where possible. This helps reduce grime build-up and keeps the cover in better condition.
Don’t treat a standard thermal cover as a safety cover
Most pool covers are not safety barriers. Children and pets should always be supervised around the pool, and proper pool fencing and safety requirements must still be followed.
What to Do After a Big Pool Day
After a busy day of swimming, the best thing you can do is help the pool reset.
Remove the cover if it is still on. Let the pool breathe. Run the pump long enough to circulate the water properly. Use the robot or vacuum if there is visible debris. Empty the skimmer basket if it has collected leaves, insects, or hair. Check the water if the pool has had heavy use, especially if the water looks dull or smells strong.
If you use a pool valet service, this is also a good time to ask for a quick water balance check. Heavy bather load can change water conditions quickly, even in a well-maintained pool.
The goal is to deal with the water before it turns cloudy, rather than waiting until the problem is obvious.
The Bottom Line
A pool cover is one of the most effective tools for heat retention, energy efficiency, and water savings. Used properly, it can make your pool more comfortable, more efficient, and easier to enjoy through summer.
But a pool cover is not a magic barrier, and it is not a replacement for cleaning, circulation, or water balancing.
In summer, your pool needs sunshine and airflow just as much as it needs heat protection. The best routine is simple:
Cover off during the day. Cover on at night. Run your robot. Keep the water moving. Test regularly.
With the right habits, your pool will stay clearer, fresher, and far easier to manage throughout the busiest swimming months.
As one of Auckland’s trusted pool companies, we pride ourselves on expert craftsmanship and personalised service. Let Auckland Inground Pools help bring your dream pool to life.
Also see our article on How Pool Water Affects Your Hair.
Contact us today for a quote
📞 09 294 7572
