In article , Simon Bloomer wrote:
- which is better, external canister vs internal power filter.

For all the reasons NetMax listed canister is better. The 304 fluval
is probably your best choice.


b) more efficient with a larger
filter volume and space for good bio filtration, but at the price of lower
filtration rates.

I would not worry about the flow rate. As you said the canister is more efficient.


Also, I like the idea of the corner surface
skimmer box which I have in my current setup. Can this be duplicated with a
canister - although I see the risk of the filter running dry if water levels
drop due to smoe problem.

This would not work with a canister, unless you had a sump. Canister
are designed to run in a closed loop pulling water from one water
level and pushing water back to the same water level. The water level
in the corner overflow will always be lower then the level in the main
tank. This will reduce the flow through the canister.

The second problem is that the overflow will run dry simply due to
evaportion. Any water that evaporates is going to directly effect the
level in the overflow. A conservative 2% a week is 3.6l. Unless your
overflow is quite large the level in the overflow will drop
significantly.