You may have just bought your first used home with a beautiful large swimming pool in the back yard, filled with shimmering clean water. You can imagine yourself sunbathing on a warm day and using your great new pool. You notice the electrical equipment that goes with the pool, but don’t know how to use it yet.

One warm weekend morning you awake and step outside, anticipating the fun of using your new pool that day. There’s only one problem. You notice with utter dismay that the shimmering clear water has been replaced by an ugly green substance floating on the surface of your new pool.

What is this strange foreign substance and where does it come from? The substance is algae, and it is the same substance that is found in mossy ponds in nature.

What Is Algae?

Algae is actually a living plant organism. Under the right water conditions, it can reproduce rapidly, using the process of photosynthesis to make its own food. Algae is microscopic, indiscernible to the naked eye until it has reproduced into millions of plants.

There are three main types of algae that form in pools:

  • green algae
  • mustard algae
  • black algae

Green algae is the most common and it gives your pool a green or yellow-green swampy look. It may form on the surface of the water or stick to the sides of your pool.

Mustard algae resembles dirt or sand accumulating on the bottom or sides of your pool. Black algae is commonly found in concrete or plaster pools.

Black algae appears as black spots on the water.

Preventing Algae

Algae is easier to prevent than it is to remove. For that reason, if you have a new pool that has not yet developed algae, you should treat the water regularly with small amounts of algaecide. Follow manufacturer recommendations for the amount to use. You should also make sure the water jets are running in your pool, which will keep the water circulating and help to discourage algae. Make sure the water filters are kept clean and they are running properly.

Dispense chlorine slowly into your pool water with the use of a chlorine feeder. Test the amount of chlorine and the pH level of your water on a regular basis with pool test strips, more frequently during swimming season. Compare the results on the test strips to those shown on the test strip bottle. Add chemicals if needed per the instructions.

Removing Green Algae

Green algae can be chemically treated. Before you treat the water, balance the pH level to 7.8. Increase the pH to that level with sodium carbonate, or decrease to that level with sodium bisulfate. Clean the filters and make sure they are running. Scrub algae buildup off of the sides and bottom of the pool. Then you can add pool shock and algaecide per product directions.

Dead green algae turns a grey color and sinks to the bottom of the pool. Clean your filters often so they can help to clean up the dead algae. Vacuum the bottom of the pool to clean up the rest.

Removing Black Or Mustard Algae

Both of these types of algae can be particularly tenacious and require a special type of algaecide to eradicate them after scrubbing out the pool. Mustard algae needs an algaecide that is copper-based and black algae requires a special penetrating agent. Consult a pool professional for additional help.

The main thing to remember about owning a pool is that it requires regular maintenance. With proper all-season care, you can swim in the clear shimmering water you always dreamed about.