Hi my pond is about 25yrs old and gets oak leaves in it in the fall. I try to rake them out around the bank to help in filamentous algae growth. I have always run a fountain and a dock deicer, fountain 24/7 and deicer 12/7. Pond is 80yds across and 15 foot deep. This is the first year I have run an aeration setup and algae is better but duckweed is out of control. The aeration I installed is a Gast pump like 4-5 cfm and ending with twin about 10 inch in diameter diffusers. Diffusers are suspended 10ft down in 15ft of water in center of pond. I have been netting duckweed seems like every other day and water clarity is foot and a half. I finally have had it and sprayed some herbicide for duckweed 1/4 around pond 8ft out. Whole pond is covered and it is a task to keep areas of surface open. I have not put in any pond dye because I do not want to add too many variables. I have been running aeration for a month first 2 weeks at 4 hours in morning and last 2 weeks 8 hrs during day. Finally getting to my question is my new aeration setup causing me more trouble than it's worth? W ish I could eat duckweed. Thanks and stay healthy

Infestations are tough to whip. How is the herbicide working?
I have no idea whether more O2 can add to the duck weeds growth but it certainly sounds like it is doing it.

I would ask Kelly Duffie about it and probably ask Lusk next Wednesday night on his Facebook program.

Pond die would not help with duckweed, since it is on the surface.

A lot of threads here on DW. It does not like moving water. Some types can double in mass in 24 hours. Look on DW treatments at AquaPlant.

https://aquaplant.tamu.edu/management-options/duckweed/

Thanks for advice, this is the first year I have had duck weed double every day. OMG I can not remove it fast enough I used the tyrap spiked rope with floats I learned about here or maybe in the magazine and corralled and scooped out. Four days later pond was totally covered again. ( the floating tyrap spiked rope worked amazingly) Thought my aeration had something to do with it since this is the first year I aerated. I cannot control the exponential growth when I do spray new growth just pushes over dead growth overnight to the bank. I am afraid to spray any more and suffer depletion of oxygen. Duck weed is blocking sun and is keeping algae in containment. I agree pond dye will be of no use now so I am thinking I should shut off aerator because it stirred up a lot of nutrient but water clarity still 1 1/2 ft. I can not remove it fast enough. Waking every morning now expecting to smell the dreaded dead fish smell. Thinking this might be a good time to move into a cave for this and several other reasons.

Forgot to ask where can I buy Tilapia in St louis Missouri area?

Tilapia are illegal to stock in open systems in Missouri. (check your PMs)

Also turning off the aerator seems like a bad idea...?

Sounds like Duckweed is taking advantage of the abundance of nutrients, stirred up by the aerators.
Now that you have good air and circulation, you might want to consider adding some Beneficial-bacteria to compete with the Duckweed!

Diquat and surfactant will handle it no problem. I like to add a few drops of dye in tank so I know what areas I've treated and don't waste too much. Duckweed will be obliterated in a few days - responds very quickly to this herbicide combo. Treat it ASAP or you could be looking at a major problem down the road.

Update, if interested, ran aerator for 24hrs and water clarity doubled so much that I had to add dye. Visibility turned to 3 foot and duck weed seems to be a little less prevalent. Somehow I have turned over the pond and nutrient has settled out now starving the duck weed?