Natural swimming pools sound like a dream—crystal-clear water without the chemicals, surrounded by lush aquatic plants. But before diving in, it’s important to understand that these pools come with their own unique set of challenges. From algae outbreaks to water circulation issues, this guide will walk you through the common natural swimming pool problems and how to handle them like a pro.
What Is a Natural Swimming Pool?
A natural swimming pool (NSP) uses biological filtration and plants to purify water instead of chlorine or salt systems. These pools have two zones: a swimming area and a regeneration zone filled with gravel and aquatic plants that filter the water naturally. They’re eco-friendly, beautiful, and low-maintenance—once everything is properly set up. But the key word is “once.” Getting there can be tricky.
1. Algae Overgrowth
Why does algae form in natural pools?
Algae is a natural part of any freshwater ecosystem, but in a swimming pool, excess algae growth can turn the water murky and unsafe for use.
Direct Answer: Algae grows in natural pools when nutrient levels (especially nitrogen and phosphorus) get too high and water circulation or plant balance is off.
How to control algae:
- Balance plant load—ensure enough nutrient-hungry plants are thriving in the regeneration zone.
- Add a UV clarifier to eliminate free-floating algae without harming the ecosystem.
- Remove decaying leaves and organic matter regularly to prevent nutrient buildup.
Recommended Product:
OASE Bitron UV Clarifier – Designed for natural and pond-style pools, this UV system reduces algae without chemical use and integrates seamlessly into most pump setups.
2. Mosquito Breeding
Do natural pools attract mosquitoes?
Yes, stagnant water and still regeneration zones can become a breeding ground for mosquitoes, especially during warm months.
Direct Answer: Mosquitoes breed in calm, still water—making poorly circulated natural pools a prime habitat if not properly managed.
Solutions:
- Ensure constant water movement using low-energy pumps or air bubblers.
- Introduce natural predators like dragonflies or mosquito fish (if legal in your region).
- Use a natural larvicide that’s safe for aquatic plants and wildlife.
Recommended Product:
Summit Mosquito Dunks – Biodegradable, safe for fish and plants, and effective for up to 30 days. Ideal for regeneration zones with standing water.
3. Cloudy Water
Why does the water get cloudy?
Cloudy water is often a sign of imbalance—whether from organic debris, excessive nutrients, or insufficient filtration.
Direct Answer: Water becomes cloudy in natural pools due to excess organic material, poor plant filtration, or inadequate biofiltration infrastructure.
How to fix it:
- Add more gravel and wetland plants to the regeneration zone.
- Install a mechanical pre-filter to catch fine particles before they enter the swim zone.
- Consider a water polisher or additional filter media like zeolite or bio-balls.
Recommended Product:
PondMAX Pressure Filter with UV – Excellent for improving water clarity in natural pools, combining biological, mechanical, and UV filtration.
4. Unbalanced pH and Water Chemistry
Do you need to check water chemistry in natural pools?
Absolutely. Even though you’re not adding chlorine, maintaining a balanced pH, alkalinity, and hardness is critical for both plant health and swimmer comfort.
Direct Answer: Yes, water chemistry matters in natural pools—imbalanced pH can damage plants, irritate skin, and trigger algae growth.
Maintenance tips:
- Check pH weekly (ideal range is 6.8–7.4).
- Adjust with natural solutions like sodium bicarbonate or peat moss filters.
- Monitor calcium hardness to protect the structural integrity of your pool liner or walls.
Recommended Product:
API Pond Master Test Kit – A reliable, easy-to-use kit that tests pH, ammonia, nitrites, and more—perfect for keeping your natural pool in balance.
5. Root Invasion and Overgrowth
Can aquatic plants take over?
Yes, if not properly pruned or selected, invasive or fast-growing species can dominate the regeneration zone, clog filters, and restrict water flow.
Direct Answer: Plant overgrowth occurs when invasive species or unchecked root systems overwhelm the regeneration zone, disrupting filtration and flow.
How to handle it:
- Choose native, slow-growing plants suited for aquatic environments.
- Trim plant roots and foliage regularly—at least twice per season.
- Use root barriers if planting aggressive species like cattails or reeds.
Recommended Product:
Aquascape Aquatic Plant Pruner – Long-reach tool designed for trimming submerged and marginal plants with ease and precision.
6. Structural Issues and Liner Damage
What if the liner gets punctured?
Since natural pools typically use rubber or polyethylene liners to hold water in place, sharp rocks, plant roots, or shifting soil can cause leaks.
Direct Answer: Liner punctures lead to water loss and ecosystem instability, usually caused by roots, rocks, or settling ground.
How to prevent and repair:
- Use protective underlayment during installation to prevent punctures.
- Check for signs of water loss weekly.
- Patch holes immediately with an underwater sealant or liner repair kit.
Recommended Product:
Firestone Pond Liner Patch Kit – Durable, weather-resistant, and easy to use even underwater. Works for EPDM liners commonly used in natural pools.
7. Cold Water Retention
Why does the water feel too cold?
Natural pools rely on ambient conditions and circulation. Without a heating system or optimal sun exposure, they can stay cooler than desired—especially in shaded or windy areas.
Direct Answer: Natural pools often feel colder because they lack heaters, are deeper, and depend on natural sunlight to warm up.
Solutions:
- Design your pool with shallow areas that heat up faster.
- Use dark liner materials to absorb more heat.
- Consider a solar-powered heating system or floating solar covers.
Recommended Product:
Sun2Solar Pool Solar Cover – Lightweight, eco-friendly solar blanket that traps heat and minimizes evaporation in natural swimming pools.
Tips to Keep Your Natural Pool Healthy Year-Round
- Clean debris weekly: Use a skimmer net to remove leaves, insects, and twigs.
- Monitor plant health: Yellowing or rotting plants can spike nutrient levels and trigger algae.
- Check pumps and flow: Keep water moving to avoid stagnation and mosquitoes.
- Winterize properly: Trim plants, shut down pumps if needed, and cover the pool to prevent debris buildup.
- Schedule seasonal maintenance: Replenish gravel, prune plants, and inspect liners every spring and fall.
Conclusion: Are Natural Swimming Pools Worth It?
Natural swimming pools offer a unique, chemical-free way to enjoy the water—but they do require a solid understanding of biology, filtration, and regular upkeep. From algae management and water clarity to preventing root invasions and mosquito breeding, being prepared makes all the difference.
Still interested? Then go for it. With the right tools and a bit of knowledge, a natural swimming pool can become your personal oasis—one that’s healthier for you and the planet. Use the recommended products above to get ahead of common issues and enjoy the full beauty of your eco-friendly retreat.