Copper Based Algaecides – How To Use Them Correctly

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Over the years, it’s been no secret that chemical algaecides, and namely those that contain copper, have been at the forefront of algae control. Many people, from golf course superintendents, to farmers, to pond care companies, have relied on them to keep ponds looking better.

(Note that what I’m speaking of here is generally for large ponds. I personally don’t like to use this type of copper chemical in any small pond)

For those that have read much of my material you probably know by now that I don’t usually endorse algaecides much (other than the copper-free Algae Off) and in particular I don’t often favorably present copper based ones. These are usually known by several names. Copper sulphate and Cutrine or Cutrine Plus are a couple of the more popular varieties.

There are several reasons why we’ve never carried either product. Since we’re very focused on environmentally friendly options for pond algae control, selling a copper based algaecide never fit that profile. Then too, it’s well known that when you kill algae on the surface the pond may look clean, but that’s far from the truth. The reality is, every bit of dead or dying organic matter (including algae) is building up at the bottom of the pond and turning it into a liquid compost pile.

If you want more algae to grow at the surface, make sure you have a good deal of decaying muck at the bottom and you’ll get plenty of algae.

Last but not least, copper is toxic to bacteria, and while this includes some of the bad bugs, the good bugs are not immune to it’s effects. When you take down these hard working microbes, it’s like wiping out the clean up crew before a forth of july parade. In other words, it’s not a good idea.

So in what could be considered a traditional application of an algaecide, it’s wrong in my opinion to treat the algae, which clears the pond, then wait for algae to develop again, and retreat. This becomes a cycle that inevitably keeps adding to the organic load at the bottom of the pond. While the surface looks cleaner, the bottom get’s more and more toxic.

You want to avoid consistent use of those chemicals that, when applied, sink fairly quickly to the bottom and concentrate there, and these include copper sulphate.

However there is some good news to report in terms of algae control and a better form of copper algaecide with which to do it.

Treating A Pond The Right Way With An Algaecide

So is it possible to use a copper algaecide and not cause major issues like this?

The answer to this is yes, but I’ll preface this by saying that I still prefer biological means when possible to deal with all kinds of unwanted issues in ponds.

But if you now use a copper algaecide, or are thinking about using one, here’s how to do it the right way.

First off, make sure you have really good aeration running in the pond. It’s well known by most pond owners, but when you have any plant die off in the pond it will pull oxygen from the water. When this is precipitated by a chemical, the die off can happen rapidly. So good aeration is a must. Also, if you can, treat only sections of the algae bloom at a time, if it’s widespread and heavy. Do this over a period of days and you should help minimize oxygen issues. And finally if it’s possible, and the algae is not overly heavy, you can spot treat accordingly and knock the existing algae down.

At the end of this effort you should end up with a fairly clean pond on the surface, and ideally you don’t want to wait to see more algae forming in a few weeks. Treat to deter more growth rather than responding to something when it show’s up. In this way, you minimize the issue of adding to organic build up at the bottom of the pond with dead algae.

Fortunately with new advancements in algaecide formulations there is now a copper based product that I believe is highly superior to use as an algae deterrant. It’s called EarthTec and what makes it so different is, instead of most of the treatment sinking to the bottom (like copper sulphate), EarthTec will actually stay suspended in the water column until it’s needed to control an algae bloom.

Generally speaking you will use less of it, less often, and the copper will be maintained in much lower doses of ppm (parts per million) in the pond water. It’s also self dispersing so it’s easy to apply. You can test the copper concentration in the pond and simply add enough EarthTec to keep it around 0.06 ppm to 0.12 ppm and this range will retard most types of algae growth.

Of all the various kinds of algae control products on the market, there’s no question that copper products do work. The question is can they be used in a way that keeps the pond looking better, without destroying the natural processes that help keep it cleaner and healthier. EarthTec moves us closer to that reality and can serve as a viable and effective replacement for pond owners that are now using much harsher products like copper sulphate.

Visit this page to learn more about EarthTec Algaecide.

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4 thoughts on “Copper Based Algaecides – How To Use Them Correctly”

  1. Mark,
    Just applied 25 lbs Algae Off plus a 1/2 ac. pro biosphere as you recommended. Since there is so much muck on the bottom, we used a boat float and suspended the sphere about 2 ft under the water to better disperse the bacteria. We were afraid the muck would not allow the sphere to do it’s job. The sphere is anchored close to our surface fountain. Are we correct? Also, will some of the algae sink to the bottom after using algae off? It’s going to take many man hours to rake.


  2. I used an algaecide (Beckett) to get rid of the green water problem I was having this summer, the result of too much sun, too many goldfish and not enough water plants. It worked very well. Now I wonder if I can still use the pond water and filters to water my plants? In the past I have used that pond for my citrus trees and herb garden. After reading the bottle of algaecide, I worry about the toxicity. Is that water safe to use?

  3. Hi John…don’t know why I didn’t get notified of your commment when it came in…but I missed it…so sorry for the dealyed response. I guess my thought on this is copper will eventually dissipate but if you’re watering often with the pond water, I just don’t know what affect it will have on those other plants. Golf courses do use copper often enough in their ponds, and they irrigate with it for their grasses, but those are not going to be eaten or edible such as a herb garden. Green water in itself isn’t the worst thing, and ideally if you can get the pond balanced out, it should go away…we use microbial products to help with that initially. You didn’t mention how large the pond is, so there are other things for green water too, such as uv light, which is specific for that problem. But I only use that in smaller ponds…maybe up to 5 to 10K gallons.

    Hope this helps for you.

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