I am maybe over my head here because I just started reading about this topic today :-).

The Horton filter is a pre-filter that goes at the intake of the line. In Horton's pictures he has a small pump inside of the colanders (the whole in the colander is for the exit line). One could also potentially stick it at the end of their intake hose if they had a bigger pump.

I think you need to cut most of the wire ties to clean it.

Kaysbelle, Milwaukeeboy is quite correct the colander/basket cage is a prefilter, to stop any pea gravel or hard object from being sucked into the pumps impeller and doing damage.
The scrubbies are used to trap the soft particulates that are drawn in by the pump.
If left alone the bacteria will colonies on the surface of the scrubbies.
But, here's the short fall. If the basket and scrubbies are the only means of filtration for the pond, it will have to be cleaned at times, depending on how much gunk it has to filter. Consequently, each time it is cleaned you will wash out the good bacteria that is starting to build up.

The idea behind this prefilter [ it is now being used by various pond pump manufactures] is to protect the pump more than anything else.

It is easier to clean than the "Adam's type" filter, which, because of the type of filter material used in it, in my opinion, tends to plug up to quickly and requires to be taken apart and cleaned regularly.
If it is not cleaned regularly then there is a danger of the pump overheating and possibly burning out.

The basket cage type can be opened up, if necessary, by untwisting a couple of twist ties, or cutting off the ty-rap, if that is what is used to keep the two halves of the filter together.

Normally the cleaning the basket type cage, can be done with a blast from the garden hose once a day.
How much or often, you need to clean out a filter is in relation to the condition of the water, size of pond and how much accumulated gunk there is to filter out.

There is no SMALL, in pond, prefilter, homemade or professionally manufactured, I have ever come across, that does not require cleaning every so often.

An out of pond filter will do a much better job of filtering than a small in pond filter. That to me, is by far, the best method to use.

I know there are folks who have five gallon pails [or other types of containers] filled with, a variety of filtering materials, in their ponds.
And though this type of filter, may do a wonderful job of keeping the pond water clear, it is not something I personally, want to look at in my pond.

Each to their own, one mans meat etc, etc.
"Horton"

Where can I see a pic of this prefilter? :-)