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Should Your Solar Pool Cover’s Bubbles Be Up or Down?

Pool covers prevent evaporation, promote chemical retention, and heat swimming pools. They also keep debris out.

However, none of these benefits are quite as useful if the bubbles aren’t facing the right direction. The bubbles on your solar cover are what trap the heat and UV rays, warming the swimming pool.

Your solar pool cover’s bubbles should be down because the bubbles absorb and hold the sun’s heat on the water. The bubbles need to be sprayed weekly to remove dried chlorine and other chemicals. Replace the solar cover once the bubbles flake or pop since they’re no longer effective.

In this article, I’ll show you why your solar cover’s bubbles need to face the pool water, how you can keep them in good condition, and what happens if the bubbles face up for too long. Let’s get started!

Which Way Should Solar Cover Bubbles Be?

It might seem silly, but the direction of your solar cover can make or break its performance.

A solar cover loses half of its benefits if the bubbles face upward. Pointing the bubbles toward the sky prevents them from absorbing enough sunlight. They’ll maintain the pool’s current temperature rather than heating it with UV rays.

Solar covers only work if they’re installed correctly. You can’t expect them to get the job done if the bubbles break apart from direct sunlight or if the underside crumbles from the strong chlorine in the pool.

Fortunately, you can flip and spray the solar cover if you’ve been doing it wrong this whole time.

I’ve often heard of customers complaining about their solar covers flaking or breaking after one pool season. Many modern solar covers last between three to five years, and some of them include warranties.

However, these warranties are voided if the bubbles face upward since it’s against the manufacturer’s instructions.

Keep in mind that 12 ml solar covers last a couple of years longer than 10 ml covers. Furthermore, they can withstand the sun’s heat and the chlorine’s harsh corrosiveness.

Nevertheless, it’s important to face the bubbles toward the water to protect either solar cover.

If you prefer a video tutorial, check out this helpful guide to measure, cut, and install your solar cover with the bubbles in the proper direction:

Why Should Your Solar Cover’s Bubbles Face Down?

Your solar cover’s bubbles should face down to prevent flakiness and chlorine damage. Facing the bubbles toward the sun will ruin them. This orientation also prevents the bubbles from retaining the heat. However, facing the cover in either direction will prevent evaporation and chemical loss.

Here’s what happens if your solar cover’s bubbles don’t face down:

  • Your pool cover won’t keep the water warm enough. The bubbles should always face down because they can’t retain the sun’s rays otherwise. The bubbles are designed to pull the heat from the widest part, which happens to be the top of the solar cover. The domed bubbles push and trap the heat under the water.
  • The top of the cover (the side without the bubbles) will deteriorate if it sits in the chlorinated water for too long. Solar covers trap the chemicals, preventing you from adding too much of them. If you have too many chemicals in the pool, make sure you lower the chlorine to prevent the bubbles from breaking apart.
  • Debris can get into the pool if the bubbles face up. A solar cover is supposed to be slightly elevated off of the water with the bubbles. However, the flat top portion seals against the water and slides around. When it moves, anything on top of the cover will fall into the swimming pool.

Regardless of which way the bubbles face, all solar covers will reduce evaporation and increase chemical retention. For this reason, many pool owners think it doesn’t matter which way the bubbles face. However, you’ll get several more swimming seasons out of your pool cover if you face the bubbles down.

Read on to learn more about aiding your solar cover’s longevity.

How to Maintain Solar Pool Cover Bubbles

To maintain solar pool cover bubbles, follow these instructions:

  1. Keep your pool’s chemicals balanced. Unbalanced pool chemistry can dry and corrode the pool cover. Chlorine, low pH, low alkalinity, and strong algaecides can corrode and flake the bubbles. Keep these chemicals in their recommended ranges to prevent your solar cover from breaking apart.
  2. Remove the algae from your solar cover as soon as possible. Solar covers prevent algae, but preformed algae blooms can eat the cover. The cover will flake and look terrible, not to mention that it will hinder its performance. Algae is one of the primary reasons people have to replace their pool covers so often.
  3. Pool Research recommends spraying your solar cover to remove algae, contaminants, and debris. I’ve always told my customers to spray their solar covers weekly, then let them dry for an hour or so before placing them back onto the pool. Your pool needs time to ‘breathe’ and off-gas to prevent chemical concentration, corrosion, and buildup.
  4. Install a pool cover reel. These reels keep your cover contained, preventing them from creasing and wrinkling. Creases can tear the solar cover or winter cover. The VINGLI Pool Cover Reel works for covers up to 18 feet across. It also comes in multiple other sizes. These reels have wheels and levers for easy, quick operation.
  5. Remove the debris and water from the top of your pool cover. Excess debris and water will drop everything into the pool, rendering the solar cover useless. Furthermore, sharp objects (sticks, thorns, rocks, etc.) can poke holes in the pool cover. Any holes in the cover can lead to tears that permanently ruin the cover.

Maintaining your solar cover is essential if you want to reap its benefits.

Flaky, leaky, damaged solar covers can cause more harm than good. They can ruin your pool’s pH, prevent its evaporation reduction, and cause algae blooms. Small plastic flakes can clog the plumbing and damage your pump’s impeller.


  • Jonah Ryan

    Jonah has worked for several years in the swimming pool industry installing and repairing equipment, treating pools with chemicals, and fixing damaged liners. He also has plumbing and electrical experience with air conditioning, ceiling fans, boilers, and more. When he's not writing for Temperature Master, he's usually writing for his own websites, and

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