The canister has a separate pre-screen section consisting of 4 rectangular sponges for mechanical
filtration, this can be removed separately from the main media compartments. There are 3 main
compartments for media, each divided into two halves, for maximum flexibility in media combinations.
Carbon pouches and hollow tube bio-media are included. The overall construction seems sturdy and
the filter is quiet in use. However, the output is not quite as strong as one might expect from a
filter of this size.
Update: (Oct 2001)
In longer term use, a couple of problems have become apparent with the filter I have. Firstly, the 'Aquastop' system, which
replaces the need for separate taps and should shut off the flow, doesn't work properly, and didn't from quite early on. It tends to become easily clogged with debris which stops
the valves working properly. This means that the inlet pipe has to be taken out of the water to prevent the water from continuing to flow.
Secondly, I have had trouble with the impellor stopping. On the first occasion, the impellor housing was ready for a clean, so this may have
contributed to it. However, because the motor remained on, the housing got very hot, and this melted the plastic part of the impellor fitting.
This may have contributed to the filter stopping a second time, after which it would not re-start. As an emergency measure, I had to use a powerhead
on the intake pipe to run the (unplugged) filter. The replacement impellor assembly which I bought did not fit the housing (!) - I am unsure whether
this is due to wide manufacturing tolerances, or distortion of the impellor housing.
In feedback I have received by email, some have suggested that the flow through these canisters may not pass through the media fully. In one case, cling film
had been placed over the top media basket, blocking the normal water path. There was apparently hardly any reduction in flow rate. While this might indicate that
the water is able to flow through the canister without passing through the media, I do not feel that this is a completely 'fair' test, because water will always take
the path of least resistance, and if the normal route is blocked, the water flow will find an alternative route. This may even be an in-built safety feature by the manufacturers,
so that if the media is very clogged with debris, the water can still flow, hence preventing damage to the filter. However, this would make it difficult to judge when the canister
required cleaning, and definately suggests the possibility that the water may begin to bypass the media as it naturally becomes clogged.