May 2012

It warmed up fast this spring, all the fish have spawned and your pond either looks perfect…or it may have a few qualities you would like to change. No two ponds are the same and some of the same ponds seem to act differently, depending on circumstances.

Let’s explore water and design characteristics that can be limiting factors for your pond. Some of those limiting factors are water chemistry issues which, if changed, could vastly improve your water quality, the size of your fish and the overall enjoyment you get as a pondmeister.

Tackle the underlying issues in the pond rather than chemically treating the symptoms.

By “limiting factors” we are talking about the elephants in the middle of the living room. Some ponds are just perfect, in that on their own water quality stays balanced, they grow big fish, are fun to swim in, attract nice wildlife and just stay pleasant, while others maybe a hundred feet away are unsightly, smelly, and covered with filamentous algae and baffle the mind. Then there are ponds that are beautiful for years then all of a sudden turn ugly.

If we look at the science behind maintaining a pond we look at what we microbiologist-people call the Big 8.

  1. Aeration—Aeration not only helps grow beneficial bacteria it also creates water movement. Water contacting air helps cleanse the wet stuff. If your pond is shallow, and gets lots of wind action then you may be okay. Wind creates horizontal movement. Aeration creates vertical movement.
  2. Muck—Muck is filled with nutrients…nutrients which build up over years of algae, weeds and leaves dying and going to the bottom. Many times, the years of nutrient build up will outpace the ability of naturally occurring bacteria to degrade it. This is when we add bacterial culture. We have seen a number of ponds clean up by just treating the nutrient-laden muck.
  3. Phosphorous—There are many types of phosphorous chemistries but in the end, phosphorous stays behind in the pond. That fact is a focus of progressive pond management today. Let’s say you use aluminum sulfate (alum) to treat your pond and lower phosphorous, and you precipitate aluminum phosphate. It goes out of the water column but into the muck. If you want to remove phosphorous, physically clean the pond or catch some fish. Fish sequester phosphorous. So, if you can use excess phosphorus and convert to fish, it can be removed. The bigger the fish you grow the more phosphorous they contain. Many people rake plant material out of the pond or even grow nice flowering aquatic plants they can harvest. This is another way to remove phosphorous. In many states pondmeisters may add more phosphate to make the pond a more productive fishery.
  4. Nitrogen—Nitrogen enters a water system through plants, animal droppings, and fertilizer but it can work its way out of the water and back into the air as a gas.  Geese are notorious for spiking the nitrogen in water as they eat and produce fecal matter all day.   Did you know a goose will poop 96 times per day? No wonder there’s an algae bloom right after they leave. There are specialized bacteria just for taking the nitrogen out.  Aeration always helps.
  5. Iron—If you have more than 0.3 ppm iron in your water there is a good possibility you will grow lots of horsehair algae, also known as pithophora. Last year we had a customer that was pumping his well water into the pond to raise the water level and the well water was high in iron and he had pithophora. Stubborn as a mule, pithophora can be treated but needs to be treated often. This customer installed a filter to remove the iron and the problem went away.
  6. Silica—Silica is the element that makes up glass, circuit boards, and a special type of algae called diatomaceous algae. The algae literally produce a protective glass cover.  They call this cover a frustule and it allows these algae to grow quickly and relatively protected.  I have never found an easy solution for this. Diatomaceous algae typically turn the water pea green and they are tough to control. To identify diatomaceous algae it needs to be tested by a lab.
  7. Buffering Capacity—Some ponds need more alkalinity to grow big fish and prevent the algae from raising the pH. Alkalinity and hardness levels are important and should be tested if you live in an area where soft water is common. Do you remember how years ago acid rain was decreasing the pH of Canadian Shield lakes?
  8. The last and most important is a bit of luck and trained decisive action.  Rains bring lots of vital nutrients and bacteria into a pond while droughts and endless sun are always tough.


Take a look at the Big 8 and see how they relate to your pond and what direction you want to go. Test for them, study your algae and learn. Ask for help from the pros and you can make wise decisions.

We have seen many ponds and lakes where residents and applicators were being patient and focused on killing bad stuff rather than understanding why they were there. After three or four years we said, “forget patience,” lets figure out what is really going on. Once you feel confident and are armed with the facts then you can act quickly and enjoy your pond this year…not three years from now. Be knowledgeable, be proactive and network with smart folks like those in the Pond Boss forum, and then act decisively. We often say “it’s not rocket science, but its close, and it’s fun”.

Here’s what you must realize. Nature responds to what it is offered. If your pond has a pH of 5.6 with alkalinity less than 10 ppm, Nature will grow something quite different than if your pH is 8.1 and alkalinity is more than 200 ppm. If you have ten years buildup of oak leaves trying to decompose on the bottom of your pond, the water chemistry will be different than it was during the first few years of its life. When you factor all these things together, your solution won’t be as simple as buying an over-the-counter solution to knock out some greenery that consistently tangles your favorite crankbait.

Use aeration to stabilize water chemistry. Use microbes to speed up the composting process underwater. Begin to understand how nature works from the bottom up to grow those giant fish you love to catch. Once you understand how water chemistry affects your favorite fishing hole, you can begin to choose the best tools to attack the problem rather than some fast-food approach to treating the symptoms.

Sounds pretty easy, doesn’t it? Well, it’s not. But, with some simple, regular testing and interpretation from those in the know, you can get outside the comfort zone of your box and change tactics.

Who knows, you might just figure out a few simple things you can do to mildly alter the chemistry of your water and those obnoxious plants and algaes might just resign protest.

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