A filtration is a filtration system, one isn't better then the other, what
makes them different is the application in which you use them. The benefit
of a pressurized system is this: If you were to pump the water from your
pond up to water fall, the water can pass through the pressurized one
without the problem of the filter overflowing. Because it's sealed like a
canister water will not escape i.e. it's pressurized. If you tried to do
this with a non pressurized one, water will escape. A non pressurized system
is more of a gravity filtration, water passes through it and filters the
water and returns back to the pond. Think of it this way, you have a
container that is air tight or you have a container with a lid that is just
placed on it, which one is more secured?
A decent pond filter with UV, I have the Tetra PUV 4000. Do yourself a
favor, what ever one you get, make sure you get a UV 18 watts


"mjl" wrote in message
. ..
I would like to know what the difference is between a pressurized filter
and a non pressurized filter. Is one better than the other? My filter
started leaking and I need to buy a filter for a 2,000 gallon pond.I bought
my filter locally, and had it for about 6 years. It was a regular filter
with no uv attached.Any advice on buying a new filter would be greatly
appreciated. I was considering buying a filter with a UV sterilizer built
in, as I didn't build any shelves in my pond and have tried to grow water
lilies on the bottom of the pond plus a number of other plants a few times
but the koi destroy them, so as a result the water is always green. thanks
for any advise