Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants FA and watermeal options

Hi All,

My first post, but have been lurking for a while. So here it goes.

2.08 acre pond with 5'9" average depth (11.96 acre feet)
ph 7 - 6.8, alk 40 ppm, hardness 65 - 75 ppm, nitrite 0 ppm, nitrate 0 ppm.

Watermeal, duckweed and filamentous and planktonic algae are becoming a problem. The pond is 40 to 50 years old and we never had any problems. The water has always been darkish brown, but of good swimming and fishing quality. Mucky bottom except for my sandy beach, no odors. Little outflow except once or so a year over the spillway with exceptional rainfall. We are planing on running power to the lake and installing an aerator if necessary. Now my specific questions:

If we use the fluridone route, what do we use in combination for the algae?
Has anyone used diquat sucessfully to erradicate watermeal? If so, how many applications/ cost?
Does an aerator prevent or serverely restrict watermeal?
Aerator vs. bacteria for bottom cleanup?

I have read a lot of info, but the packaging and combining of different herbicides and algaecides with and without bacteria is quite confusing to me.

Your input is greatly appreciated.
Thanks, Roland

Roland, welcome to the forum. Glad you decided to jump in! Another Virginian is always welcome...

Duckweed is very susceptible to fluridone. Creating a 45 ppb concentration over a 45+ day time period should eradicate it. The fact that you have minimal outflow will help keep the ppb up. Generally you want to add 50% in the initial dose, 25% 7-10 days later and the last 25% another 7-10 days later. Watermeal is also susceptible to fluridone, but is a bit hardier. A concentration of about 90 ppb would be needed. Obviously, this concentration will also kill the duckweed.

Diquat is a lot of work, requires multiple treatments and the plants often come back... Where as with the fluridone, particular in a pond like yours where there is minimal outflow, one treatment often last into the 2nd or 3rd year and keeps it from coming back.

Along with the fluridone, a copper-ethanolamine based treatment like citrine-plus can be used to eradicate the algae. Spot treating floating matts of the algae is best to prevent fish kills. Species like trout, channel cats and koi are especially sensitive. So keep that in mind if you have these species and value them...

Aeration will work to reduce the duckweed and watermeal. It will also help to evenly distribute the fluridone treatment. In my opinion, aeration if properly installed and ran is the best investment one can make in their pond... It can be used in conjunction with the bacteria. Hopefully someone with a bit more experience with bacteria can weigh in.

Has there been a change in the land usage around the pond recently? Increase run off from lawns, farm animals, etc? As ponds age, they also build up nutrients which makes them more susceptible to issues like duckweed and filamentous algae.

No change in land use over the last 10 years. We have hay fields and horse pasture around the pond. The pond used to have trees and scrubs on all sides, so one could hardly get to the water. About 10 years ago, we cleared 3 sides to make the pond more user friendly.
We stock full size trout every October and they live until end of May, early June depending on water temperature, but the do not survive the summer. We also have channel cat's, black crappy, largemouth bass and blue gills. We never had a fish kill.

Would jet ski use help with aeration? My closest power source is 1000' away. If bacteria clean up the muck some, we may not need to run a power line.

Also, we never feed our fish. If we use fluridone, will we have to start feeding? Thanks

You won't "have to" start feeding, but it will get the fish to grow faster. Even with a pond 1,000' away from power, you can bury flexible black poly tubing that far and still get enough air to the pond. I'd bury 1" tube, and reduce it to the 1/2" self-sinking air line once it reaches the pond. Go with what CJ recommended and you should have your problem solved. The jet ski will only mix the top of the water column, not top to bottom like a bottom diffuser/aeration system.

Bacteria in conjunction with aeration is the best bet. Look for a company that makes it's own bacteria. Esshup has a great idea. We routinely bury air line as it is cheaper and safer than running electric. The right bacteria will not only reduce the muck on the bottom, but can clear the water, removing nutrients, thus reducing future problems with algae and other plants.

Thanks,
But if I have to trench, I will prob. run electricity to the pond, maybe a gazebo, lights etc.

Depending on your budget, trench, run conduit and airline to the pond might be less expensive than wire for the aeration system. Running a compressor will need some pretty heavy wire for a 1,000 ft. run plus any other load you might want to add later.... You can always add the wire to the conduit later.