While plant dye may work to limit the CLPW, it will limit all of the microscopic plants also, which are the base of the food chain. I don't feed my fish, so I worry how that would possibly limit the ponds capability. Also I am not fond of the dye-look, sort of looks fake to me.

Yet another option is to nuke from orbit (via chemical action) and start from scratch plant-wise, I have given that thought also.

I am leaning towards grass carp simply because it is a natural way to capture those pond nutrients, and let some plants live on yet limit the growth rate of the existing plants.

If I were at the 80% mark of coverage, then getting a balance would likely be next to impossible, but I think I have a shot at my lower coverage of keeping it there. Only time will tell I guess.