One of the seasonal plants we use comes from florida. The name escapes me "fibro fog". It is a plant that the Us considers dangerous to local waters, but they sell them here. the are floaters and spread quickly. they die off in the fall.

In florida they have infested the local ponds and lakes and are killing out the local plants, they also use up the oxygen in the water, so if they get to dense they can kill fish too. Not a problem in your pond as you can trim them out.

You want to have 60 - 80 % of the surface area covered by plants! this keeps the water cooler, removes a lot of the algae food source, and naturally keeps the water clean.. My lilies return each spring bigger than before with multiple blossoms all summer, they are beautiful, just leave them in all winter, they can handle it fine.

Netting is a good way to help keep it clean and to keep out the Heron, I just hate to do it, I like being able to just walk out and sit by the pond with out having to remove the netting to see clearly. Lazy I guess.

Comets and Koi are fine in muddy water Its us that want it clean. Asure sign things are ok in the pond is when the frogs move in They are very sensitive to water quality and will leave if it is poor...

Well I am glad to hear that they survived the winter, as I wrote earlier, I let it freeze over and everything was just fine..