We inherited a garden pond with 20 or so fish between 8 and 15 inches long. The pond is approx 3m by 2m x 800mm deep.
The previous owner had just not done anything to look after it and it was in a bad way. The water surface is free from algae and is not green or anything and a nice leafy floating plant grows well (we keep this cut back to about 1/3 to 1/2 coverage to provide fish shade.) But the water is not clear at all, we can't see the bottom of the pond, which is also very silted up. Have bought a pond vac but it is not making much difference and need to give the pond a good overhaul. The submerged pump seems fine (jetting the water out at a very good rate when disconnected from the filter box) but the water flow from the external filter (and down to the waterfall) is very slow in comparison.
We have deduced that it is a new filter that is what we need but are confused as to what is the best way to go with all the options and absolutely no experience.
The combined submerged pumps and filters that can run a waterfall - and a fountain - look attractive, but with so many fish do they have enough filter power to be efficient?
As the existing submerged pump seems fine, do we need to just buy a new external filter box?
Can anyone recommend a good - but not too expensive - external filter that is easy to clean and maintain?