"bk" wrote in message ...
We use a Tetra PF3 cannister type filter with a 1100gph pump. The water
inside the cannister is stays very high. The local fish store tells me that
the water in the cannister shouldn't be so high. Anyone else use this
filter?

Yep I have one and I modified it. I got rid of the carbon mat it came
with because it was to dense. I did this to prevent it clogging and to
avoid backed up water which is then diverted to the filter walls. I
put a bag of mini bio balls on top of the stock round sponge pad, Then
added a layer of 12" x 12" pads (not very dense) including a much less
dense carbon pad of the same dimensions I then put a round plastic
diffuser which is the bottom of a plastic oil change container
(Walmart) on top of my layer of pads. I cut the diffuser down to about
3/4 of an inch in height and drilled holes all over it including holes
in its sides. I put a finer mat directly in the diffuser and directly
under the water. I change that mat and only that mat every few days
just by reaching in and grabbing it. I have low maintenace because the
most accesable pad catches the vast majority of the dirt.

What is the actual water flow rate in gph flowing into the the top of
the PF-3 ? You could see how many seconds it takes to fill up a 1 or 2
gallon container. Mine is around 600 gallons an hour and I have no
water back up problems. If your actual water intake rate into the
filter is over 1000 gallons per hour than there is to much water for
that filter according to
instructions.


steve