Keeping a pool clean and debris-free is a top priority for any pool owner, especially during off-season months when a pool cover plays a critical role in protecting the water. One of the most persistent and unsightly problems pool owners face is algae growth on pool covers. Algae not only ruins the appearance of your pool area but can also harbor bacteria and damage your cover if left untreated. In this in-depth guide, you’ll learn everything you need to know about how to get algae out of a pool cover, why it occurs, and how to prevent it from coming back.
Why Algae Grows on Pool Covers
Algae growth on a pool cover is surprisingly common and occurs due to a combination of environmental and maintenance factors. Understanding the root causes will help you combat this issue more effectively.
1. Stagnant Water and Moisture Buildup
Pool covers often collect standing water from rain or condensation underneath the cover itself. This damp, dark environment is the perfect breeding ground for algae. Unlike in a swimming pool, where filtration systems can help manage algae growth, pool covers lack any such mechanism—allowing algae to thrive unchecked.
2. Exposure to Sunlight and Organic Debris
While you might expect a pool cover to block sunlight, certain types (especially mesh covers) allow partial light penetration. When combined with leaves, twigs, pollen, and other organic debris that gets trapped on the cover, the stage is set for algae colonies to grow.
3. Inadequate Winterization and Maintenance
Failing to properly winterize your pool or maintain your safety or winter pool cover during off-seasons encourages algae formation. Without the circulation of water or proper chemical application, covers remain vulnerable surfaces.
Tools and Supplies for Cleaning Algae from Pool Covers
Before diving into the cleaning steps, gather the right tools and products that make the process efficient and safe for both you and your pool cover material.
Essential Cleaning Tools
- Brush (soft to medium bristle, depending on material)
- Garden hose with strong spray nozzle or pressure washer
- Algae removal solution or pool cover cleaner
- Plastic scraper for stubborn stains
- Bucket
- Protective gloves and eyewear
Recommended Cleaning Solutions
- Pool cover-specific cleaners (avoid generic cleaners that might degrade the fabric)
- Mild detergent mixed with water
- Diluted bleach solution (use sparingly on vinyl or heat-sealing covers)
- White vinegar for eco-friendly cleaning options
Step-by-Step Instructions for Cleaning Algae Off Your Pool Cover
Before you begin, make sure the cover is attached to a solid framework (if it’s a safety cover) or is completely pulled taut (if a winter cover). If you’re dealing with a pool cover that is too heavy or cumbersome, consider removing it, placing it on a flat surface, and then cleaning it.
1. Remove Standing Water
The first and most crucial step is to eliminate standing water using a pool cover pump or a siphon-style drain. Failing to remove water creates a loop where algae continuously grows, even during and after cleaning. Allow the cover to begin drying out before proceeding.
2. Brush the Algae
Using a soft or medium bristled brush, start scrubbing the surface of the cover where you see algae buildup. For mesh covers, brush both sides—the top and underneath—to remove as much algae as possible.
3. Apply Cleaning Solution
Whether you opt for a dedicated pool cover cleaner or a DIY solution (such as white vinegar and water or a bleach and water mix), evenly spray or pour the cleaner across the cover’s surface. Allow it to sit for 10–15 minutes to break down the algae and its roots.
Diluted Bleach Solution (Optional for Stubborn Algae)
| Solution | Concentration | Notes |
|---|---|---|
| Water + Bleach | 1 part bleach to 10 parts water | Recommended for vinyl covers only |
| Water + Vinegar | Equal parts of vinegar and water | Safe for all cover types |
4. Rinse Thoroughly
Using a garden hose with a strong spray nozzle, wash off the entire surface, making sure to completely rinse away the dead algae and cleaning residue. Especially important with bleach solutions—residual bleach can weaken materials. For convenience, a pressure washer set to a low-pressure setting can help expedite this step, but be cautious with high pressure to avoid tearing mesh materials.
5. Inspect and Repeat if Necessary
After rinsing, visually inspect the cover for remaining algae stains, especially in shaded or damp zones. If stains remain, repeat the cleaning process with slightly stronger concentrations or longer dwell times.
6. Dry or Wipe the Cover
To reduce the chance of rapid regrowth, ensure the cover is completely dry before resuming normal use. Wiping down remaining moisture with a clean towel or squeegee, especially in corners and edges, is highly beneficial.
Tips for Preventing Algae Formation on Pool Covers
Cleaning algae is essential, but the long-term goal should always be prevention. The following proven strategies will help you extend the lifespan of your pool cover while preventing unsightly algae issues.
1. Maintain Proper Water Chemistry Before Covering
Before covering your pool, ensure the water chemistry is balanced:
- Chlorine levels: 1–3 ppm
- pH level: 7.2–7.6
- Alkalinity: 80–120 ppm
Balanced water before closure not only protects your pool equipment but also reduces contaminants under the cover that support algae growth.
2. Use a Pool Cover Algaecide
Adding a non-staining pool cover algaecide specifically designed for winterizing can drastically reduce algae problems. These products are safe for covers and help the pool water resist microscopic algae spores.
3. Regularly Remove Leaves and Debris
Even during off-seasons, check on your pool cover once a month and manually remove debris that collects on the top layer. You can also consider using a leaf net underneath a mesh cover to reduce algae-feeding material from settling on the cover.
4. Install a Cover Pump or Automatic Debris Remover
Automatic cover pumps help reduce standing water build-up, which is one of the main catalysts for algae. A high-quality pump with a float sensor can be a worthwhile investment in long-term pool maintenance.
5. Avoid Excess Tree Shade
If possible, trim back overhanging trees. Shaded covers not only retain moisture, but the leaves from trees accelerate debris accumulation, making algae problems worse.
Different Types of Pool Covers and Their Cleaning Needs
Not all pool covers are created equal. The materials and function of your pool cover influence the cleaning method and preventive strategies.
1. Solid Winter Covers
Made from solid vinyl or reinforced materials, these covers are typically designed to block sunlight and keep debris out. They often allow water to pool on the top and have a leaf net below to trap fallen debris.
- Cleaning Tip: Use a mixture of water and mild detergent. Avoid harsh bleach unless explicitly recommended by the manufacturer.
2. Mesh Safety Covers
Mesh covers allow rain to filter through but still collect algae-friendly debris on the top and undersides. They are strong and can support swimmers, making them ideal for safety purposes.
- Cleaning Tip: Pay attention to underside algae. Use a soft brush and non-abrasive cleaner for both sides.
3. Automatic Pool Covers
Used during the swimming season, automatic covers roll open and closed at the touch of a button. While not exposed to algae growth for extended periods, they can still develop mildew if not maintained properly.
- Maintenance Tip: Periodically wipe down surfaces and ensure the tracks and mechanisms are clean.
Protecting Your Pool Cover for Longevity
In addition to algae cleaning, it’s essential to maintain your pool cover overall to increase its lifespan.
1. Store Covers Properly During Off-Seasons
After cleaning, ensure your cover is fully dry before folding or storing it during summer months (if winter cover) or vice versa. Fold gently without creasing and store in a cool, dry area. Use breathable material bags over plastic to avoid moisture build-up.
2. Avoid Harsh Chemicals
While bleach can help with occasional cleaning, never substitute it for purpose-made pool cover cleaners, especially for long-term use. Harsh cleaners can wear out fabric and weaken UV-resistant coatings.
3. Reapply Protective Coatings
Some premium pool covers come with UV and weather-resistant coatings. Over time, these degrade. Consider using waterproof sprays or UV protectants recommended by the manufacturer to refresh materials after deep cleaning.
When to Replace Your Pool Cover
Unfortunately, even with proper care, no pool cover lasts forever. If your cover is showing signs of:
- Significant discoloration and staining,
- Rips, holes, or grommet wear,
- Loss of elasticity or tension,
- Or if algae keeps coming back despite cleaning
…then it might be time for a replacement. Most pool covers last around 6–12 years depending on the quality and maintenance.
Conclusion: Keep Algae Growth on Your Pool Cover at Bay
Knowing how to get algae out of a pool cover is a critical part of swimming pool maintenance. While the process may seem daunting at first, with the right tools, techniques, and preventive care, you can easily manage and eliminate this persistent issue. Implement a regular cleaning schedule, ensure proper water chemistry prior to covering your pool, and protect your cover with routine checks.
Keep your cover clean, and you’ll not only improve your pool’s aesthetics—but also make opening day much easier, healthier, and hassle-free.
Remember: prevention is always better than cure. Regular maintenance saves you time, protects your investment, and ensures the best possible performance from your pool cover season after season.
What causes algae growth on a pool cover?
Algae growth on a pool cover typically occurs when the cover is exposed to sunlight, moisture, and organic debris over time. Unlike in a pool, where chemicals help control algae, the surface of a pool cover lacks this treatment, making it a prime environment for algae spores to settle and multiply. Additionally, if the cover is not cleaned regularly or stored improperly when not in use, algae can easily develop and cling to the fabric or material.
Environmental conditions such as high humidity, warm temperatures, and the presence of nutrients from dirt, leaves, and bird droppings can further encourage algae growth. Covers stored in damp or shaded areas are especially susceptible. To reduce the risk of algae, it’s crucial to keep the pool cover dry when not in use, clean it regularly, and store it in a cool, dry location away from direct sunlight.
How can I remove algae from a vinyl pool cover?
To remove algae from a vinyl pool cover, start by removing any loose debris with a soft brush or broom. Mix a solution of water and a mild detergent or a dedicated vinyl-safe cleaner, then apply it liberally over the algae-affected areas. Using a soft-bristle brush, scrub the surface thoroughly and rinse with a garden hose. For tougher algae stains, a diluted bleach solution (1 part bleach to 10 parts water) can be used cautiously, but be sure to rinse the cover thoroughly afterward.
After cleaning, allow the cover to dry completely before storing or placing it back on the pool. To prevent future algae growth, consider applying a protective vinyl coating or an algaecide formulated for use on vinyl surfaces. Also, avoid leaving the cover in standing water or under continuously wet conditions. Regular maintenance and proper storage practices can significantly prolong the life and appearance of a vinyl pool cover.
Is it safe to use bleach on a pool cover to kill algae?
Bleach can be safely used on some pool covers to kill algae, but it’s important to take precautions to avoid damaging the material. If you decide to use bleach, dilute it properly—usually one part bleach to ten parts water—and apply it to the affected areas with a sponge or soft cloth. Allow the solution to sit for about 15–30 minutes before scrubbing gently and rinsing thoroughly with clean water.
However, not all pool covers can tolerate bleach, especially those made of certain fabrics or treated materials. Always test the bleach solution on a small, inconspicuous area first to ensure it doesn’t cause discoloration or degradation. Moreover, protective gear such as gloves and goggles should be worn to prevent skin or eye irritation. It’s best to consult the manufacturer’s instructions or contact their support to verify bleach compatibility before proceeding.
How often should I clean my pool cover to prevent algae?
It is recommended to clean your pool cover at least once every season, or more frequently during periods of high humidity or heavy debris accumulation. Weekly inspections and light cleanings—such as brushing off leaves and spraying down the cover with water—can help prevent algae spores from taking hold. During the off-season, when the cover may be left in place or stored, it’s wise to give it a more thorough cleaning before putting it away.
Additionally, applying an algaecide or protective coating designed for pool covers can offer an added layer of defense between cleanings. The more consistently you maintain your pool cover, the longer it will last and the fewer issues you’ll have with algae, mold, and mildew. Always allow the cover to dry fully before storage to minimize microbial growth and maintain material integrity.
Can algae on a pool cover damage the pool underneath?
Although algae on a pool cover may seem like a cosmetic issue, it can indirectly affect the pool water quality and equipment. When rainwater or moisture accumulates on the cover, some of the algae and dirt may seep through or drip into the pool below, introducing contaminants that can upset the chemical balance and potentially lead to algae blooms in the pool itself. The cover may also retain a musty odor that transfers to the pool water, causing unpleasant smells.
Moreover, a neglected, algae-covered pool cover may deteriorate faster, leading to tears or weakness in the material that can compromise its effectiveness in keeping debris and sunlight out of the pool. This could result in increased maintenance costs and effort on the pool itself. Regular cleaning of the pool cover, therefore, is essential to both preserve its function and protect the water environment below.
Are there any products specifically designed to prevent algae on pool covers?
Yes, there are several products on the market designed to prevent algae growth on pool covers. Algaecides formulated for use on vinyl and fabric covers can be applied on a regular basis to inhibit the growth of algae, mold, and mildew. These products are usually safe for the material and won’t stain or deteriorate the cover. Some are designed specifically for use in between cleanings and can be easily sprayed on and rinsed off.
In addition to liquid algaecides, there are protective coatings and sprays that add a barrier to the pool cover’s surface, making it less hospitable for algae development. Covers with antimicrobial treatments are also available for purchase, offering built-in resistance to microbial growth. When choosing any product, always read the manufacturer’s recommendations to ensure compatibility with your specific type of pool cover and to avoid potential damage.
What should I do if my pool cover has mold or mildew along with algae?
If your pool cover has mold or mildew in addition to algae, it’s best to treat all three simultaneously, as they often coexist in damp, dark environments. Begin by scrubbing off any loose debris and rinsing the cover with water. Apply a mixture of water and mild detergent or a specialized cleaner designed to handle mold, mildew, and algae on fabric or vinyl covers. Gently scrub the solution into the cover, let it sit for a few minutes, and then rinse thoroughly.
For more persistent cases, a diluted bleach solution or a vinegar-water mix may be necessary. Follow the same steps: apply the solution, wait, and scrub again before rinsing. Always ensure that the pool cover is completely dried after treatment to prevent regrowth. Long-term prevention includes regular cleaning, proper storage, and using protective sprays or algaecides to maintain a clean, healthy pool cover.