More information seems in order.

The filter is an Aquascape "BIOFALLS" filter. The contractor who put
it in suggested not to clean that often as it would kill off the
benefial bacteria. I believe the recommendation was to change out the
filter once a year. It looks generally clean (or at least not clogged
and too soiled).

The pond gets a LOT of morning shade and then afternoon and evening
sun.

I am using supposedly beneficial bacteria - the Aquascape Clear
bacteria plus SAB enyme. I haven't tried (but thinking) Barley (which
as I understand it I can place either in the pond or in the water
course. I am tyring to get the lillies to cover at least 60% of pond.
What I am trying to figure out is how to make sense of ALL the products
out on the market. There seem to be scores of different "bacteria"
products. Are there any reviews????

Woudl just like to see the bottom of my pond at some point ;-)