I imagine some of us feel that way about your plants. There are so many good things about plants.

As you know, they make the tank more pleasing to the eyes. They help bring out colors in some fish which we didn't realize were there or could be so intense. They shelter fry and harassed adults.

They also contribute to the well being of the tank by absorbing ammonia and providing surface upon which micro-foods grow - nourishing grazing fry. With egg laying fish they offer yet another spawning surface and with livebearers about to drop, they offer some solitude for birthing.

I suppose you could say they even allow us to cheat a little on water changes. Don't take that too far though. (Do as I say, not as ...) :)

In the dark, again as many of you know, plants somewhat reverse the photosynthetic cycle. They stop absorbing CO2 and producing oxygen and even release some carbon dioxide back into the water. In crowded tanks that might be a problem at night. Your water fall/filter in all likelihood sufficiently moves the water to and from the surface (when the gas exchanges take place) and your fish are safe.

That discoloration of the water is a bit puzzling. I would look to the bottom and odd corners of your tank and see if the plant canopy is so shading some plants or leaves that they are dying. In quantity the decaying plant material could be a bit of a problem. Clip brown and discolored leaf sections off. Siphon debris before it decays too much.

Some of us layer tanks, having "low light plants" (among others) such as Java moss, Java fern, and Crypts on the bottom layer. The Aquatic gardeners actively take scissors and trip cuttings from their garden (making themselves very popular with other aquarists.)
I'm dumbfounded by the mention of compost piles some Aquatic Gardeners have "out back."

Just the other day someone on the Killietalk list noted that he threw out great handfuls of Java moss. Somewhat agitated, I suggested selling it and putting the kids through college. ;)

See the following for starters:
http://www.csd.net/~cgadd/aqua/index.htm
http://www.aquatic-gardeners.org/

I gather that there are tight restrictions on what may be shipped out of Oz. So Trans-Pacific swaps are out.

But if you (in what spare time?) checked around on-line or in other ways, you might find others from Oz to swap plants with.

Maybe do google searches for combinations of: Australian Aquarium Plant Club.