Is your water filter enough for the size of your pond?
A poor water filter often means poor water quality for your pond life.
Pond Water Filtration
The market place is full of the good, the bad and the ugly, (not that any filter can be classed as beautiful!) This is an area where we are very careful to make statements, but each manufacturer has a product that has a use, as to how good it is that maybe up for debate and certainly not on this web page.
Generally we find filters are undersized for many ponds, that’s not to say they are fish killers far from it.