I'm putting this in the Aeration forum because I'm thinking that aeration is the best approach. The pond is a cousin's about 3 hours away in the Kansas City area so I will have to depend on someone else to carry out any solutions, which makes me very hesitant to use chemicals for control.

It is a 3 acre, 15 foot maximum depth, spring fed pond which overflows through a spillway several times a year after a rain. Has been there at least 50 years. It is also surrounded by trees that block the wind. The last time I was there, it was a 10 mph wind in the open but couldn't feel any at the pond. The pond surface is covered by a thin green layer, some duckweed but I'm guessing mostly watermeal. Lots of frogs and some snapping turtles, but don't know about any fish.

Water testing in late July 2019 was: pH 7.0, nitrite 0.0, phosphate 0.5, ammonia 0.5. My theory is that the trees both block the wind and have contributed to a build up of bottom muck over the years. From the test results, the anaerobic bacteria are converting the muck to ammonia, but there isn't enough oxygen for the aerobic bacteria to convert the ammonia to nitrite, etc. When I was there about a week ago we put in a couple of pounds of muck away pellets along 2 parts of the shoreline and poured in a couple of gallons of pond dye plus bacteria, mostly because I already had bought it.

I'm looking at the Airmax 40 system which is supposed to be for up to a 4 acre pond. Can run electricity from the house a couple of hundred feet away up to the pond dam. Or there is a shop several hundred feet away from the side of the pond and up above it.

Am I on the right track?

Welcome to the forums HaBI!

I can't give any direct advice as I have not had to fight a watermeal/duckweed explosion, but I can certainly direct you to the area of the forums where you can find some good reading on the subject...

http://forums.pondboss.com/ubbthreads.php?ubb=postlist&Board=14&page=1

Scan the thread titles for Duckweed or Watermeal for some conversations on the subjects.

The best way to search the Pondboss forums is to go to google search and type in...

site:forums.pondboss.com Duckweed watermeal

This will search the forums for any threads with the words duckweed and watermeal. This works much better than the forum search function and the above search yielded at least a couple pages of threads talking about the control of those plants.

A can say that an aeration system is not going to solve your troubles. It may help, but not much I'd bet.

I purchased a home with a 1acre 10' deep pond. During the summer I got watermeal bad totally covering it. I bought some Clipper and a surfactant and sprayed heavily. At the time I did not think I had any fish so I wasn't concerned of killing fish. I went thru 2 maybe 3lbs of Clipper and then put in aeration. I stocked some fish last year also. This year there are no signs of watermeal and I have caught some of the fish from last years stocking. I was told by some people this I was going to have to drain it to get rid of it. But I didn't need to.

To Quarter Acre: This past winter I've read about every post on Pond Boss from the past few years. I've also seen your same advice to several other new posters. This thread was about a water meal problem and what help aeration might provide, if any. Not a googling problem.

However, I've just found out that my cousin has a terminal illness with possibly less than a month left. Pond issues are now on the self, perhaps permanently.

To HaBi, Sorry my efforts were of no help.

Visited the 3 acre pond this past weekend during a family reunion. It looks like the pond site will be remaining in the family for at least the next few years.

As expected, the pond was totally covered with duckweed and water meal. Also saw lots of bull frogs. The 2 biggest problems seem to be the trees surrounding the pond, and the trees surrounding it. 80-100 years of leaf litter on the bottom and very little wind getting to it to stir up the surface.
I've suggested to the person living there that they could make some fish traps to sample what might be in it besides frogs and turtles.

We also talked about using an aeration system starting next spring when the water temps warm up. There is electricity less than 100' below the pond dam, so I'm thinking to put the aeration unit on top the dam and running 4 diffusers, 2 would use 100' of sinking tubing each along the face of the dam in the deeper water, and 2 using 200' of sinking tubing each for further out in the pond. Then try aeration for a year to see how much it helps before starting to dump chemicals, pond dye, or bacteria into the water.

Year two might need to try spraying something like Clipper? Although it would be costly for a 3 acre pond and the goal for now is to just have something to look at besides a complete covering of green.