Fellow pond and water gardeners around the world sometimes struggle to achieve water clarity. Their pools of water have turned into pea soup or has become infested with algae. The battle never seems to end and they can’t seem to find a light at the end of the tunnel. Chemicals are brought in and while they sometimes temporarily help, often times they make the situation worse. So what is the secret for having a clear pond? Well, its simply “patience, education, and nature.” Yes, that is correct!
Think back 
of why you first desired a water garden. Perhaps it was a place to unwind after a long day of work or maybe it was a perfect addition to your backyard. The sound of water trickling–feeding fish–even the sights of nature: birds, bees, and butterflies. Lets not forget dragonflies and damselflies. Water gardens can be thought of as a micro ecosystem in your yard. They need a balance or they won’t be appealing. The path to correcting your troubles begins here…
About algae
The two most popular forms of algae
that cause problems in ponds are pea soup (green water) and string algae. Rather than bore you with fine details, just understand that these particular types of algae feed off excess nutrients. These can come from your water source directly, excess feeding, an overstocked pond, etc… If your algae is a result of your habits such as overfeeding then you must immediately cut back food portions; if it is a result of an overstocked pond, you must either add significantly more filtration or keep your best fish and locate new homes for the others. If you have been using chemicals such as algaecides, you must immediately stop and set them aside.
The solution
Green water algae and string algae can be corrected in 
the same way. The only difference when following this guide is that you will need to remove the string algae daily until it is minimal or nonexistant. Green water can be corrected with 60-70% surface coverage. Ideal candidates for this job would be tropical water lilies. You’ll also need submerged plants. Some people refer to them as oxygenators butwe find this misleading because while they do produ
ce oxygen during the day, at night time they consume oxygen in the water! We also recommend marginal/bog plants that are planted in containers with holes at the bottom (the roots will eventually find their way out the bottom and they will filter your water biologically). You may also consider adding lily-like aquatics–these plants grow similarly to water lilies and they also have surface foliage that aids in providing shade. You will also need some floating plants as well.
- Tropical water lilies: N. ‘Foxfire’, N. ‘Blue Aster’, N. ‘Avalanche’, N. ‘Lindsey Woods, N. ‘King of Siam’, N. ‘Pink Flamingo’, N. ‘Sandra Lynn’, N. ‘Charlie’s Pride’
- Submerged plants: Hornwort, Anacharis, Najas Grass
- Marginal/Bog plants: Parrot’s Feather, Thalia, Green Taro
- Lily-like aquatics: Floating Heart, Water Snowflake, Mosaic Plant
Floating plants: Duckweed, Water Hyacinth, Azolla (Fairy Moss), Water Lettuce
We recommend plants that are easily accessible to you. For example: we maintain a high plant stock of tropical water lilies as that is the business that we are in but we can acquire hornwort and anacharis from the local pet store. As for najas grass, it is traditionally used in aquariums but it is a native plant to Florida. We also use duckweed which doubles as fish food.
We also highly recommend you check with your local agriculture
extension agency as some states prohibit particular plants. For example, although water hyacinth is across existing Florida waters, it is illegal to possess.
As for the amounts of the plants to use, we mentioned prior that you should use tropical water lilies to achieve surface coverage of 60-70% but for submerged and floating plants we recommend adding
as much as possible. Some sources push a system is which you add bunches of submerged plants that correlates to the gallons of water in your pond but this system is broken because there are many variables that it does not account for. In short, “more is less.” The more plants you add, the quicker your pond will move to achieve a balance. Once you have ideal water clarity, you can remove portions of the plants slowly to gain back water surface. Rather that throw them away, opt to share with a fellow ponder. Do not release into local bodies of water!
Tips
- A minimal amount of algae is beneficial to your pond or water garden. The algae that will coat the sides of your pond liner is good algae–you’ll see your fish pick at it.
- Some fish will devour duckweed and azolla rather quickly! Set aside a separate pool of water to allow some to regenerate and add to pond as desired.
