I have used diquat to control it with not great results. Finally decided to add some aquashade dye which has helped more this year but it is still a bit of a problem in my 1/2 acre pond.
The plant in your hand is a good picture. Its common name is Small Pondweed also Slender Pondweed technical name is Potamogeton pusillus. Your use of blue dye forces it to live in shallow water.
Grass carp and tilapia like to eat this delicate tender pondweed. Put in just enough GC to reduce it by 50%. No more than 1 or 2 GC in 1/2 ac. Leave them in until they get a least 24"-30" long to see how much they will eat each summer. One GC can eat a pickup bed loaded with this pond weed each year. Leave some about 25% of the pondweed always grow to compete with filamentous algae by absorbing nutrients needed by FA. FA lives on nutrients not being used by other plants. If GC eliminate the pondweed they will start searching sediments for invertebrates and make the pond turbid. GC do not like to starve. A 1 or 2 GC plus tilapia will do a lot to reduce your plant problem by 50%-60%. Try to remove 10%-25% pondweed each year to remove some pond nutrients. When you get ALL the pondweed consumed it will be replaced in biomass by FA. Pondweed is easier to deal with than FA. Nature demands something will use the available nutrients. Manage the nutrients with plants that you can live with.