How to Control String Algae in Your Oklahoma City Metro Area Pondless Waterfall

by | Aug 10, 2023

Yes, you’ve seen that nasty green gunk stuck to the rocks and gravel of your Oklahoma City Metro Pondless Waterfall. That’s probably string algae, an organism that commonly hangs out in moist areas, feeding off excess nutrients in the water.

String algae is a natural, normal, expected, and beneficial part of a balanced ecosystem in a pond or waterfall.

Almost every Oklahoma City Metro Disappearing or Pondless Waterfall has some string algae. It won’t hurt anything when present in moderate amounts. If you don’t mind the way it looks, you can usually leave it alone.

But what if string algae takes over – or you simply get tired of looking at it?

Fixing the problem is usually easy to do.

String Algae in a pond

Treating String Algae

You know now that string algae is normal. But not everyone necessarily wants to look at it while enjoying their waterfall.

We do have some tricks to help you get rid of it.

1. Add More Plants
The easiest way to keep string algae at bay is to add more plants to your waterfall. String algae eat nitrates – a nutrient that naturally comes into the waterfall when beneficial bacteria do their work.

Plants also eat nitrates. Each type of plant you add to your waterfall will take in a different kind of nitrate – i.e. a red leaf will absorb one type, a green leaf another. The more and wider variety of plants you add to your waterfall, the fewer nutrients are left to feed string algae.

Variety is important and comes in many forms: different leaf shapes and colors, different flower colors, early-season grower versus later-season, a tropical plant versus a hardy plant.

Not only does having a variety of plants work to reduce string algae, it really makes your waterfall look awesome too!

Regardless of what plants you add, you’ll know they’re doing their jobs if they grow big leaves and flowers – meaning they’re taking in lots of nutrients – and the area downstream from them has minimal string algae.

2. EcoBlast or SAB
Plants will always give you the best defense against string algae. But if you already have a huge variety of plants in your waterfall, and you’re still not happy with the results, you can buy a few products to give your waterfall that final polish.

The first product we recommend for getting rid of string algae is a powder contact algaecide like SAB or EcoBlast.

Always follow the instructions on the container of any algaecide, but here’s a quick overview of how to apply EcoBlast in a waterfall:

1. Turn off your waterfall and sprinkle a small amount of the product directly on the string algae. You want to use enough that you can see it on the algae, but not so much that the algae looks like a sugar-dipped strawberry.

2. EcoBlast takes effect immediately. The algae will start to bubble and look bleached.

3. Wait at least 10 minutes to give the product time to work before turning your circulation system back on.

4. Use a net or your hands to skim out the algae as it breaks away from your rocks. Any dead algae you let decay in your waterfall will act as food for new algae, undoing all the work you’ve just done.

5. Wait a couple days to do a second application if needed.

Contact algaecides and algae-control products often work better in warm weather, so you might have to wait longer to see results in early spring than you would in the summer.

3. Liquid Algaecide
Liquid algaecide will also kill string algae. To apply it to your Disappearing or Pondless waterfall, simply pour the algaecide into your basin (where the water disappears) per the dosage recommended on the bottle.

Like with EcoBlast, you’ll still need to make sure your waterfall has enough plants to prevent algae from returning.

4. IonGen
Some pond owners like to install an ionizer for constant string algae deterrence. These devices – marketed under names like the IonGen – release copper ions into the water through a probe, creating conditions that string algae don’t like. They’re a powerful tool if you don’t mind the up-front cost, plus the cost of replacing the probe every one to three years.

Contact our Service Team if you’d like us to install an IonGen in your waterfall.

5. Autodoser with Prevent
The Automatic Dosing System for Fountains automatically adds specially formulated water treatments to Disappearing Waterfalls, eliminating the guesswork and routine of adding products manually.

If your waterfall already has an Automatic Dosing System, simply run the Prevent for Fountains pouch per the instructions. You can double the dosage temporarily if needed, or switch to the Clean for Fountains pouch until water clears. Each pouch treats up to 500 gallons.

Only run your autodoser when temperatures are above 40 degrees. You’ll need to shut down the autodoser in winter to avoid damage to the system.

If your waterfall does not have an autodoser, they’re easy to install. Contact our Service Team if you would like us to install one.

6. Unplug the Waterfall for 24 Hours
String algae needs consistent moisture to survive. Take away the water, and it will dry up and die.

For best results, unplug the waterfall for 24 hours. This dry period will give the rocks a chance to dry in the sun, killing the string algae.

7. Leave It Alone
String algae is a normal part of your waterfall’s ecosystem. If it’s not excessive, and it doesn’t bother you, you can leave it be.

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