Does Algae Grow Under Pool Cover? And How To Prevent Its Growth
Do solar pool covers cause algae growth? The covers will not cause algae growth on their own. But if the pool already had algae spores, the pool cover can keep the water temperature at 60 to 80 degrees Fahrenheit, and algae thrives in such.
When the swimming season comes to the end, that is, at the start of fall, you might want to extend it by a month or more. To do that, you can use a solar pool cover to keep the water temperature good enough for swimming.
There are many benefits of using a solar pool cover. Not only does such a cover help you to keep your pool warm, but it also reduces evaporation.
While a heated swimming pool in winter racks up the energy bill, using a solar cover for the pool saves you money, although you cannot use it in winter.
But just like anything else, swimming pool solar covers have their flip side. Many people are concerned that these covers may cause algae growth in the pool.
Is this true? That is what we are going to find out in this short post. But first things first.
What are solar pool covers?
As the name suggests, these are large covers that are placed over the pool. They come in different materials such as plastic or vinyl.
You can order swimming pool cover on Amazon.com. It looks like the one below:
These covers have many benefits for the pool owner. First, they keep the pool free from debris, since they protect it better than a net cover.
Secondly, they are not called solar covers for nothing … It is because they trap the heat from the sun and transfer it to the water. They can make it considerably warm and help you to extend your swimming season.
Thirdly, covering the water minimizes evaporation. If you don’t lose a few gallons to evaporation, it means you don’t need to buy more chlorine or anything. This saves you money.
During the day, these covers trap the sun’s heat, and they continue to warm the pool even during the cold night of fall.
Do solar pool covers cause algae? The whole truth!
This is a genuine concern from people who own pools. You see, algae need nutrients (mainly phosphate), warmth and moisture to thrive. These two factors are in plenty when you use solar covers for pools.
I can categorically tell you here that a pool cover will not primarily cause algae growth. And that is the truth!
But if there was already algae growth in the water when you applied the cover, the cover will increase the algae in the pool, because it provides warmth.
If there were no algae in the pool, the cover would not bring some, unless of course it was being used in another pool that had algae.
Apart from that, there is no other way that a plastic or vinyl pool cover would introduce algae into the swimming water.
There is a small chance of a pool cover causing algae growth in the pool – poor storage.
If it is exposed to algae spores, the cover can introduce them to the water. But you can prevent this by sterilizing the cover before using it on the pool’s surface.
Why a swimming pool cover boosts algae growth
If you realize that the algae levels in your swimming pool have increased after you started using a cover, it is because of the following factors:
1. It keeps the pool airtight
The swimming pool cover is stretched tight over the pool such that the chlorine does not find a space to off-gas, it interferes with the pH balance, which in return causes the growth of algae.
Thankfully, the best quality pool covers are designed to prevent this. They enable the air movement from the pool to the outside and vice versa.
That is how they maintain the chemical balance in the water.
2. Higher temperature
Warmth makes algae thrive. Thus, if there are algae spores in the water, or the pool cover was stored improperly, and it introduced these spores among other debris, the algae will start to grow and thrive.
Remember, keeping the swimming water warm is one of the reasons for using the pool cover.
3. Worn out pool covers allow debris to get in
Even when preparing your pool for winter, you are advised to use high quality covers. The same applies to the swimming pool cover that you use to prolong your swimming season.
Chlorine and exposure to the elements do their number on the cover, wearing it out sooner than you might think.
If you have had your pool blanket for many years, perhaps it is time to check its state and replace it if necessary.
4. The pool cover is not installed properly
If the solar pool cover is not aligned well during installation, it might leave a part of the pool uncovered. This means that algae spores and debris will find a space to get into your water.
How to prevent algae growth in the swimming pool
If you do not take your swimming pool maintenance seriously, algae will grow. You will know you have algae in the water when it starts to turn green.
Here are a few things you can do to prevent the growth of algae in your in-ground or above ground swimming pool:
1. Shock the pool before covering it
Shocking the pool with chlorine is recommended when you are preparing it for winter. Pool shock treatments can help to kill algae and prevent its growth. Follow the instructions carefully when shocking the pool to avoid overdoing it.
Remember to wait the recommended time before swimming in a pool after shocking it. Since the shock kills all the algae and other organic matter, it will be safe to cover the pool.
Shock the pool regularly. If you ever find yourself asking: what is the green color in my pool, you are too late.
It should never get to that level. By then, there is too much organic growth in the pool and you have delayed shocking it.
Even in summer, shock the pool regularly because people pee in pools, there are feces, and other nasties.
2. Store the pool cover properly
As aforementioned, it is not strange for a pool cover to introduce algae spores to the swimming pool. When you store the cover, make sure it is clean, and dry.
Also, store it under the right humidity, say, 30 to 45%, so that even if it is exposed to some moisture, mold will not grow.
3. Clean the pool cover before using it
Even if you stored the pool cover under the right conditions, clean it well before you can use it. Shocking the pool before covering it and cleaning the solar pool cover before using it is a sure way to prevent algae growth in the water.
4. Don’t use a worn out pool cover
Using a worn out solar pool cover is the same as using no cover at all. If it allows algae spores and debris into the pool, it is no good.
If you can, don’t use a low quality pool cover to save money. The cheap varieties might not allow proper off-gassing, which interferes with the chemical balance in the pool.
5. Install the cover properly
If the solar cover is misaligned during installation, the water is exposed to debris and microorganisms. The latter could include algae spores, which will establish a colony in the water.
6. Use an algae starver
Algae feed on phosphate build-up that grows in neglected swimming pools. This is their nutrient, and warmth helps them to thrive.
If you have been facing this problem in your pool, you can order a high quality algae starver on Amazon.com to kill the phosphate build-up.
Conclusion: Does a pool cover increase algae?
A pool cover is going to increase algae if the same existed in the water in the first place. But if a pool cover is kept clean, sterile and under good condition all the time, it is not going to introduce algae into the water.
So the answer to whether a solar pool cover causes algae growth, the answer is yes and no. If you neglect the proper care of your pool, it will cause this problem.
If you take care of your swimming pool as outlined here, you can keep the algae out for good.