Chemical Algae Control

Could We Be Changing?

I am grateful that many people are becoming increasingly aware of our environment and how important it is to treat it well. I am seeing more and more people choosing organic lawn treatments rather than chemical treatments, and I am also seeing more and more people choosing to maintain their ponds naturally rather than chemically.

This is great to see, considering that when I started landscaping and dealing with ponds in the 80s, people were mostly clueless regarding the dangers of chemicals in the landscape industry. No one really read past the headline that said, “Have a beautiful green lawn.”  or “Have clean pond water with no algae.” Now, we are beginning to understand that chemical manufacturers really only have their bottom line in mind, not so much the environment and our health.

Many Pond Owners Are a Bit Stuck

Sadly, though, I still go to many meetings where the people have been chemically treating their pond for many years and are basically stuck with the choice of either continuing the vicious cycle or spending a great deal of money to dredge the pond or begin to treat it naturally. These are often larger subdivision retention ponds with a group of homeowners who are responsible for the upkeep. Usually, one of the homeowners whose house is closest to the pond is designated as the one who gets to meet with me and get a bid to present at their upcoming homeowners association meeting. Unfortunately, when it comes down to dollars and cents, the people who look at and interact with the pond daily may care about how it is treated. But, to the majority of the homeowners in the community, it is out of sight, out of mind, so more likely than not, the vote will go toward the cheaper option of continued chemical treatments.

I wish I were here to tell you that I have come up with a natural pond treatment solution that is cheaper than chemical applications, but in the short term, that is certainly not the case. Natural pond treatment can certainly cost thousands of dollars more than chemical treatments. How much more will depend on the condition and size of your pond.

On the other hand, given enough time, commitment, and patience, the natural approach can pay off. To get the pond to the point of becoming easier and cheaper than it is with chemical treatments, we need to get systems in place to help the pond balance itself. Once the pond rids itself of much of the accumulated debris and nutrients from years of chemical treatments, then we will start to see the health and financial benefits. Mother nature is powerful. If we help get the pond started in the right direction, Mother Nature will pitch in and do most of the heavy lifting in the future.

The Trouble with Treating Algae With Chemicals

Chemical treatment is the most common approach to algae management when it comes to retention ponds and larger, privately owned, natural-bottomed ponds. There are many more pond and lake guys spraying chemicals than there are people committed to the natural approach, which is unfortunate for our environment.

Understanding the Cycle

To understand why we might want to move away from chemical treatments, I think it is important to understand the cycle that we start when we treat ponds this way.

Algae is an abundant and important organism for the life of the entire planet. It is also quite hardy and resistant to consistent chemical treatments. Although it is not a plant, it lives on the nutrients in our pond water. There is no such thing as a pond with low nutrient levels and excessive algae, so when we kill algae with chemicals, we are simply eliminating the symptom, not the cause.

In the natural pond treatment world, we approach things from the cause side. Our goal is to lower the nutrients in our water to a level that starves out the algae and unwanted plants. This way, we can balance the entire ecosystem rather than just eliminating one symptom.

Algae, being so adaptive, can actually become more resistant to chemical treatments over time, which only leads to more chemical use. We have found this to be true in the agriculture industry as well, with weeds becoming resistant to herbicides. It is also believed that algae can go dormant for a time while the chemical levels are high so that they can spring back to life once the chemicals wear off.

Those who are pro-chemical see the algae disappear almost magically and think that they have solved a problem. Unfortunately, the truth is that they have just caused a bunch of new problems. By dumping chemicals in the water, they have indeed killed some algae, caused some to go dormant, killed a bunch of beneficial bacteria and microorganisms, and increased the nutrient levels in their pond with all of this new dead material that is settling to the bottom.

More debris + Fewer Organisms taking in nutrients and breaking down debris = Excess nutrients = Fertilizer for more algae.

Now imagine years and years of chemical treatments, and you can quickly understand why these ponds are filling up with thick and stinky muck. Since the pond is pushed out of balance because we killed off beneficial organisms, the debris will break down more slowly than it would otherwise. This will create a compounding effect of thick layers of debris and less and less oxygen on the bottom of the pond. This is why so many pond owners are looking at hefty dredging bills after many years of this chemical dosing. 

Some Insight into Chemicals

Maybe if we know a bit more about the chemicals, we will be a bit more careful with their use.

  • Sodium percarbonate – a pesticide that is toxic to birds, bees, and other beneficial insects exposed to direct contact with blooming crops or weeds.
  • Hydrogen peroxide – is less dangerous than treatments such as copper sulfate, but it is still a poison that kills other organisms in the water.
  • Copper sulfate – copper is a heavy metal that does not biodegrade and can be toxic to life of all types in low concentrations. It is a bioaccumulation risk, like other heavy metals, such as mercury, which means that once an organism ingests it, it remains in that organism and can be passed up the food chain to the predators of that animal. This is how a bit of chemical in your pond can inadvertently affect a hawk, owl, or eagle that consumes a fish from your pond. In the case of fish and other pond organisms, this copper is taken in during the respiration process. Copper is highly toxic to most invertebrates and the juvenile forms of most amphibians.When used in water, copper sulfate can create a hazard to humans. Copper sulfate can be easily absorbed through the skin. If swallowed, it can cause burning pain, nausea, diarrhea, headache, shock, and unconsciousness. The EPA has classified copper sulfate as a class 1, highly toxic chemical.
  • Potassium Hydroxide – caustic chemical that can cause severe damage to skin, eyes and lungs.
  • Ferric Oxide – has been found to cause serious inflammation of the lung and liver when inhaled by rats. I wonder what it does to our fish and frogs?
  • Calcium Hydroxide – is a pond sterilizer, raising the pH quickly and dramatically above tolerable levels for most aquatic organisms. It should be used carefully, avoiding contact to the applicator, and never used in ponds containing desirable fish.

Any time we kill any member of the aquatic food chain, we have a definite negative effect on the health of the ecosystem. The overall negative effect will depend on what type of species live in that ecosystem and their relative positions in the food chain. Still, any negative effect on an aquatic ecosystem’s food chain or diversity will undoubtedly have adverse effects on the entire system.

Knowing all of this, I hope that you give more thought to the natural approach to your pond and lake management and make a concerted effort to move away from chemical use. There are many ways that we can manage our ponds without killing organisms in the process. I feel like too many people are trying to take the perceived easy way to manage their pond without realizing the amount of damage they are doing to the ecosystem. I doubt that the chemical sellers are pointing out the long term negative effects of this sort of treatment. Just think of how nice it would be to know that your pond water is safe and healthy for any organism that might come into contact with it. This is all possible without the hazardous chemicals, we just need to put forth the effort and educate ourselves.