Lava rock is used mainly for beneficial bacteria to form not to
mechanically filter. I little bit of both is preferred with the lava
rock being surrounded by filter pads.

This is what I have in my bio filter and the water looks clean enough to
drink !!

Rick wrote:
So I put in that second pond this year and had problems with my water not
clearing up.

So I put in a bigger pump and a Skippy filter. The pump is a 3000GPH and
the Skippy a 100 stock tank. Of course I couldn't find that filter stuff
so I used lava rock. I can change it every year if need be till I find a
better filter material. Three days and my pond is clearer then bottle water
and maintenance free. I'm loving it.


"Courageous" wrote in message
...

Ooops, sorry. I took the word literally.
The originator did indicate " I also added a bog filter about 5 X 2 X 1.5
feet"

Sure. Note the upwell of water from the pond. This water will be
oxygenated:
aerobic bacteria, in other words.

C//