Kurt wrote:

I was thinking about it being one big veggie filter with lots of
Hyacinth, etc. Water enters and leaves on top. My last one wasn't
covered - just looked like a small pond.

I have seen several plans for a veggie filter that have the dirty water
enter from the bottom through a distributed piping system and usually
through a gravel bed and then exit the top. Is this overkill or even
better filtering?

Chip