Q&A for How to Get Rid of Algae in Ponds

I have a small reflecting pool with a fountain and I use a chlorine tablet for pools to keep the water clear and algae-free. In spring I use a whole tablet, but during the summer months I break a tablet in half and it will last about a month. It works very well.

Do you have it in the proper soil? Have you fertilized it with a pond-safe fertilizer recently? Both will contribute to lotus bloom.

I would not as it takes oxygen to digest the food. Most treatments will lower oxygen levels.

Try putting a small straw bale in the pond. It will break down and release hydrogen peroxide, which will kill the algae naturally.

You'll need to completely drain the pond and clean the bottom to remove all of the algae. Remove any fish or plants from the water and drain the pond with a pump. Remove as much algae as you can before cleaning the rest of the empty pond with a solution made of 1 part vinegar to 1 part water. Refill the pond as normal and take good care of it to stop the algae from returning.

No, it will come right back as soon as it gets wet again.

Yes, as fish are not essential to a pond.

You shouldn't need to use hydrogen peroxide to clear algae from the pond, as it will damage the lilies. Use a bale of barley straw instead, which will produce a weak concentration of hydrogen peroxide over time instead.

Algae thrive off of sunlight, so it will normally grow more in the summer months than it would during winter. Treat your pond for algae at the start of summer to keep it from forming, and remove any algae that has formed when summer comes to an end.

Follow the instructions listed in the article above.

You could use a weedkiller to get rid of them, or if there is water you could use a net or a scraper to get it out and then use a dustpan and brush to get rid of the extra. It works with my koi pond, so it will most likely work for yours. You will only need to drain the water if the algae situation is severe.

You'll need to find another method to destroy the algae before you can plant the duckweed. Try any of the other steps above to get rid of the algae before trying to add any new plants to the pond.

If none of the more natural methods are working, you may need to move to a chemical solution. Try using pond dye to stop algae from forming at the bottom, or use a stronger algaecide to kill the algae that has already formed.

Many of the chemical and mechanical solutions listed here will work for a pool as well as a pond. Make sure your pool filter is clean, install an ultraviolet light sterilizer, and vacuum the pool for any algae that has already formed.

Barley straw will slowly kill algae naturally as it rots. If you have a pond or body of water you want to keep free of algae, try tossing a small bale of barley straw into it. You can also use creatures that naturally eat algae to kill it. For example, tadpoles and some aquatic pond snails love to snack on algae and will eat any they come into contact with.

There are plenty of fish and creatures that eat algae that you can use to control it in your pond. The common pleco, mosquitofish, and grass carp all eat algae. So do tadpoles and a few types of aquatic pond snails. Introduce these natural algae eaters to prevent algae from forming in your pond.

While adding hydrogen peroxide can temporarily increase the oxygen levels and combat algae, it can cause damage to the gills of any fish that comes into contact with too much of it. If you're trying to add more oxygen, use an aerator or a chemical solution that is specially formed for ponds with fish.

It’s called a suckermouth catfish. It is not recommended to put one in a pond as they do not survive well when there are temperature changes.

It won't clear it. It helps to prevent algal growth, but it is not able to clear an already algal-filled pond. Try the steps above instead.

Larger capacity pumps are rated by horsepower (HP). To determine the size pond pump, first you need to calculate the volume of water in the pond. To calculate the volume of water in gallons, simply multiply the length x width x average depth x 7.5.

Use a very long bristle brush, one similar to a dryer vent brush. The string algae sticks to it well and once it hooks on, you can just pull it out. Any floating bits you’ve missed, you can scoop out with your skimmer net.