Protect Your Pond’s pH Levels From The Effects of Rain


This article will explain how rain can negatively affect your pond by changing pH levels and offer tips to maintain an appropriate level to help prevent fish loss as well as nuisance algae buildup. 

Is Rain Good for My Pond?

Rain can be beneficial to your pond by providing a free, soft water supply that does not have chemicals like chlorine or chloramine. This “free” resource often will not have harmful chemicals but presents many dangers of it’s own to your pond. Rain water varies from area to area with heavily industrialized locations putting more pollutants in the air and your water.

ponds ph level rain

Leaves, fertilizer, and other surface runoff will negatively effect the pH levels of your pond by blocking out sunlight, altering the chemical compound and ultimately creating a dangerous environment for your inhabitants.

Make sure to be proactive by removing algae, leaves, and other debris that will find it’s way into your pond after rain.

An acidic pond can quickly became harmful to your fish and using rain water is not recommended. There are filtering systems that should remove any remnants of contaminants. Erect a cover over the outside of the pond to prevent the rain water from entering the fish water. Though it may be tempting to collect and store rain water it is not advisable.

Why is Acid Rain Harmful to your Pond?

Despite the scary title, acid rain can be simply explained as a mixture of wet and dry deposited material (nitric and sulfuric acid). Technically, it refers to any form of precipitation with a pH value less than 7 which makes it a danger to fish, plants, and shrimp. Algae will do just fine in lower pH levels.

What the pH system boils down to is the overall concentration of hydrogen ions in a given sample of water, each descending value representing a tenfold increase in concentration.  For example, a pH of 4 would have ten times the hydrogen ion concentration of pH 5, and one hundred times that of pH 6.

What Causes Acid Rain?

As depicted in the diagram above (and I’m sure you’ve already guessed) the main causes of acid rain are man made.

While a small percentage of the pollution released in the atmosphere can be attributed to nature (volcano plumes, etc.), most comes from automobiles, power plants, or the burning of coal and oil.  How frustrating that we are partly creating our own dilemma, while others are working to protect our ponds and lakes from acid rain.

How Acid Rain Effects your Pond’s pH Levels

The Environmental Protection Agency states that “the ecological effects of acid rain are most clearly seen in the aquatic environments, such as streams, lakes and marshes.”

As we’ve outlined in our article on pond algae control, an improper balance of nutrients in your water is a key trigger for harmful algal bloom in ponds.

Rainwater is the #1 vehicle for these nutrients to enter your habitat.  Whether it is the leached aluminum from the soil or chemicals and fertilizers from surrounding areas, any imbalance will promote algae growth. However, algae blooms may be the least of your worries.

acid rain pond

Aquatic life can be at risk following acid rain fall.  The process is quite simple, but can be deadly if unchecked. Acidic rain causes aluminum to be drawn from the soil and carried to the nearest pond, lake, stream, or ocean.  Not only is there now a strange element introduced to your pond, but the pH is lowered after the addition of the acidic rainwater. The combination of these two factors has been studied and proven to be toxic to fish & plants. Try scooping out all algae mats, quickly clearing away material blocking sunlight, and maintaining a balanced pond through supplements but don’t try to reduce the pH by using pH-reducing chemicals.

Acids can often cause a pH crash that will kill your fish.


Pond Keeping Tips About pH Levels:

  • Algae raises pH during photosynthesis and lowers the pH during respiration.
  • Your pond changes pH throughout the day and is lower in the evening or early morning before the sun.
  • Fountains, waterfalls, and circulating pumps will aerate the water reducing how much the pH changes.
  • The pH range should be 6.5 to 9.0. Fish can become stressed in water with a pH ranging from 4.0 to 6.5 and 9.0 to 11.0. Fish growth is limited in water with pH less than 6.5 and reproduction ceases. Fish risk death at pH less than 5.0 and stand almost no chance at levels less than 4.0 or greater than 11.0.
  • The pH will be lower as the algae dies off. Whatever you do, do not try to reduce the pH using pH-reducing chemicals, acids and the like. In backyard ponds this often causes a pH “crash” that will kill the fish.


How to Protect your Fish from Acid Rain

There are many things you can do to prevent or fix the physical aftermath of an acidic downpour including scooping out algae blooms, string algae, and other mats keeping sun out of the pond. Checking your pH regularly will help you stay on track of your pond’s performance. However, these precautions and solutions will do nothing for the chemical composition of the water.

Protection of fish against acid rain hinges on keeping the pH balanced, and dissolved oxygen levels high. Using Nualgi Ponds is proven to aid in both of these endeavors as well as the added benefit of producing extra fish food, removing algae, new pond syndrome prevention, and balancing your pond.

Start dosing your pond today, and keep your mind at ease for the entire rainy season!

Why not save some stress and stop the problem before it begins? We’re confident that our breakthrough supplement for controlling algae in a pond will help you in the fight against the effects of acid rain, and we would love to join the battle on your side!

Most popular blogs:

Sign up for our newsletter

Our Pond Blog and Pond Help pages are full of helpful resources to make managing your pond easier.

If you’re still struggling, don’t hesitate to reach out to our team of Pond Experts.

Meet the Nualgi Family!

Signing up will send you a coupon code for 10% off your first purchase. We’ll also keep you updated with loads of helpful pond maintenance tips and giveaways.

    Your Cart
    Your cart is emptyReturn to Shop

    This website uses cookies to ensure you get the best experience on our website.

    Sign up for our newsletter and receive 10% off your first purchase!