you could build yourself a diy filter
this cost my friend under £20 to make
the design is here all he used was
a storage tub,
a bit of clear plastic to make the partitions,
silcone to hold and seal pipes & partitions in place
,you can have them filled with filter wool in the middle 2 bays empty in the last ,
he used a fountain pump connected with a bit of hose
he used this to clear the dead algea and fines to clear his pond as his nexus easy pod wasnt collecting the fines
and he was having to clean it every other day as the blanket weed and algea died off
oh forgot to add you can also do thid with a water butt with a tap on the bottom a bit of hose a bit of pipe silcone filter wool and a grate to keep filter wool off the return pipe