In just 1/4 ac of water maybe dipping it out as it floats up may be the best way to deal with it. You should be able to remove lots of it in one hour using a long handled 1/4 mesh net. Look for a smelt / shad net. Removing it removes the nutrients that it absorbed for growth. Killing it just recycles those nutrients back into the pond for growing the next plant episode.
https://www.basspro.com/shop/en/bass-pro-shops-shad-smelt-shrimp-net 6 ft handle
There are smelt nets available with longer handles up to 11 ft. Longer handles increases shipping cost.
If you are somewhat 'handy' you can buy just the dipping net with no handle and adapt it to fit a telescoping threaded extension pole from a Big Box Store. Some of these handles are long - maybe 20 ft.
One option is a: 15 ft. Telescopic Commercial Swimming Pool Pole (3-Piece) 1 1/4" pole OD
or
HDX POOL SKIMMERS - Nets Heavy-Duty Aluminum Leaf Rake for Swimming Pools and Spas Home Depot
Just the Net Head for adding your own handle.
These nets are very durable and built with the Monorail Hoop that protects the netting from abrasion. The netting channel reinforces the hoop against bending or breaking. The peripheral cord holds the netting securely in the hoop.
http://www.jonahsaquarium.com/JonahSite/netdipnet.htmPerfect Dipnet Net Head Only includes the hoop, netting and yoke. Yoke accepts 1-1/8 inch diameter round handle. Other yoke sizes may be special ordered. This is the net head only without a handle. Hoop is 16.5 inches wide and 20 inches long with yoke.
1/4" Mesh plus smaller mesh sizes
Model 1H Net Head 16.5" hoop, White 1/8" Ace netting x 10 inches deep $33.00 Order
Model 2H Net Head 16.5" hoop, Black 1/8" Ace netting x 10 inches deep $33.00 Order
Model 4H Net Head 16.5" hoop, Green 1/8" Ace netting x 10 inches deep $33.00 Order
Model 7H Net Head 16.5" hoop White 1/32" Micromesh Bug Netting x 10 inches deep $33.00 Order
