Pond Algae Control Tips

Pond algae control doesn't have to be complicated or complex. In fact if you know a few basic things as a pond owner, you'll likely make great strides in keeping your pond from turning green this summer.

Here are five tips that will help clear up almost any pond or water garden. By applying some or all of these suggestions you'll create a cleaner and healthier pond and avoid the need to use too many treatments and algaecide chemicals.

Control Algae By Focusing On Nutrients

The foundation of limiting algae blooms in ponds really comes down to one simple thing. Controlling and managing nutrient levels in the water.

Like every living plant on the earth today, algae needs certain things to thrive and apart from water and light, the food of the plant comes down to organic elements that they can consume and transfer into life sustaining energy.

Plant foods usually have some form of phosphates, nitrates, or organic substances that in simple terms might be called fertilizers.

So the focus of our suggestions are all designed to lower or minimize these types of nutritional things that algae might find appealing.

Use Good Plants To Fight Bad Plants

I'll use the term "good" and "bad" here loosely. Algae, for as much as people may not like it, isn't the demon it's often labelled to be. A little green tint to the water or a few clumps here and there are no big deal. Algae can serve as fish food for some, and a sort of natural pond balancer for others. But moderation is the key.

When string algae takes off or an ugly scum builds up on the surface, a once pristine pond can turn into and eye-sore. And this indicates other things are probably not quite right in the water as well.

So from a holistic approach, we could look at algae as an indicator of another problem with nutrients. They are probably too high and could be troublesome if left alone.

One great option is to add the "good" or desirable plants with the hope that they'll choke off some of the algae.

This isn't as far-fetched as it might sound.

Plants like floating lilies, water lettuce, or any marginal that can cover some of the waters surface actually help beat algae in two ways. First they too like the same things algae feeds on and can often outcompete it for this valuable support. Also light plays a part in algae growth and by covering some of the surface, less light becomes available to the algae.

Can plants alone keep algae from forming? Sometimes would be the most accurate answer. Often a pond owner will need to cover about 65 to 75% of the pond with plants to have an effect.

If you don't want to use that many lilies, there are other additional things you can use with the plants that we'll cover below. (hint: think beneficial pond bacteria)

Watch Your Fish

Let's stop kidding ourselves into thinking that a pond will have an unlimited capacity to hold fish. Year after year, fish multiply and grow, and on both counts, they will add to the nutrient load that a pond will have to deal with.

Good filtration, plants, and algae treatments will help for awhile, but at some point, they will not be able to hel much if fish populations get too large for a pond size.

At that stage, you as a pond owner have one choice, and that's to get some of the fish out of the pond.

Koi owners run into this problem more than someone who's dealing with goldies or comets. Koi produce A LOT of waste and this discharge adds up quickly into high nutrient loads. Another more deadly issue that can come up is ammonia spikes that are really stressful on fish.

Most of this can be avoided by keeping an eye on your fish.

So how many are too many?

Numbers and ratios vary depending on who you talk to, but one rule we use is 25 gallons of water for each inch of koi fish. Cut this amount in half for goldfish.

If you have algae, and you think you might have too many fish in a pond, this is a great place to start to get everything back to balance once again.

Use Good Bugs And Microbes

Sometimes the term "bacteria" really freaks people out. You get sick from that stuff don't you? Well yes, and not. Bad bacteria does exist but there's also good bugs too. These do a lot of the clean up work in nature and have always been a part of a balanced ecosystem. They're found in ponds, in the dirt, even in your body. And we couldn't do very well without them.

It's the same with your pond.

In order for it to stay clean and relatively clear, bacteria must be present to do the clean up work. Beneficial bacteria actually consumes nutrients that algae likes. Like plants, it can outcompete algae for support and choke it off from the primary source of what helps it grow.

Bacteria will also help eat away at organic material in the pond and help it break down into harmless substances. When you do this you keep a lot of bad things in hand...like ammonia spikes, and other risky issues for fish.

Overall, the pond can become cleaner, and more healthy without using chemicals.

Now that I brought it up, let's talk a little about algaecides and how they differ from bacteria. Chemicals like this are designed to kill algae directly and they are useful to a point. The problem is (in our opinion) many people over use them and expect them to take care of the problem of algae. They will usually clear things up for a time, but over time, they also can cause a lot more problems.

If you're killing algae on the surface, that algae has to go somewhere. It doesn't just vaporize. So it sinks to the bottom and adds to the organic load in the pond. Now here's another issue with algaecides. They can also damage or kill good bacteria! So what's left to do the clean up chores? Not much.

When the bacteria base is destroyed, you'll be the one doing most of the cleaning in the pond. Draining and cleaning a pond is something you'll want to do from time to time, but it isn't something you should have to do regularly unless something is out of kilter.

So our general pond management routine is to try and use bacteria for the brunt of cleaning. We may use an algaecide for touch ups and areas like waterfall streams. Otherwise we let bacteria do the work and will only use chemicals after we've tried just about everything else.

Pond Filters And More

There's no question if you choose to have fish in your pond that you'll want to install some form of a pond filter system. Fish place higher demands on a small pond and mechanical options are a really great way to deal with that.

There are many filters on the market today and it's worthwhile to do your homework before buying one. Generally you want to get one that's big enough or has enough capacity to handle your pond's needs. This includes using the total gallon volume of the pond for seleting a filter but also planning well ahead...maybe years ahead on how many fish you'd like to have in the pond and how big they might get.

There are times when you might literally want to double the size of the filter for the pond's size, just because you might want to create a home for more fish. It may sound crazy to go this overboard, but this type of thinking will pay off in the long run.

There are mechanical filters which do nothing more than strain out the material that gets into the water. These will usually require regular cleaning. Then there are the biological filters which by design, do most of the cleaning themselves. They actually have the aforementioned beneficial bacteria in the filter that do the cleaning and digesting.

If we had to make a suggestion, we would go with a biofilter above other options. You can even build one yourself and we've included a short video for a diy bio filter. You can pretty much design a filter system to fit any need.

Another useful too for some types of algae is a ultraviolet light. This application uses uv light to damage single cell algae which may kill some of it, and make others clump together which will allow better filtering from an accompanying biofilter. It's extremely important to run the water through the uv tube at a specific rate that will allow it time to work. Too fast of a flow and the algae may pass without being unaffected.

It must be remembered that UV isn't perfect for everything algae type. It can work well on green water issues, but it will not help with string algae since this mass form can't pass through the tube. Also if you use bacteria, it's likely that some of the little bugs will be damaged by UV. This won't happen if the flow rate is high enough usually, so again, experimentation may be necessary to get the best results with a UV light.

Monitor Conditions In Your Pond

And finally, although there's no set answer on what you should check in your pond from time to tme, it's not a bad idea to get an idea of the pH swings that your pond will go through. pH will change throughout the day but ponds that have a fairly neutral pH (something around 6.5 to 7.5) will tend to get better results with bacteria. If pH is below 6.0 or above 9.0 then natural solutions, or most of them anyway, will not work as well. And pH will vary around the country and even in local areas, depending on the amount of lime in the ground water.

If you have fish, it's really useful to keep an eye on ammonia and oxygen levels. The latter is a bit harder to check on since the easiest way to do this is with a digital monitor. Ammonia however can be very toxic to fish, and this can be monitored through inexpensive test strips. Just dip them in the water and check the color changes on the strip.

Some test strips and devices will also check nutrient levels such as nitrates and nitrites and are useful to some extent. If you have algae issues, it's pretty much a given that you have high nutrient loads, or algae wouldn't be there to begin with.

So if you have a problem with pond algae, look for sources of nutrients or things that could be affecting the nutrient level in the pond. If there's been a good bit of rain, consider run-off as an issue. Work at keeping leaves and organic material out of the water. This includes grass clippings, mulch, and other natural substances.

Experiement a bit with how often or how much you feed your fish. Absolutely make sure that most of the food is consumed immediately and does not sink to the bottom.

And keep filters and other mechanicals in good working order. Do not skimp in getting a good system set up at the outset, and try your very best to be patient when setting up a biofilter. Resist the temptation to clean these out routinely since each time this is done, bacteria colonizing will need to be re-established.