Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
How about running the filter on a tub of water, or as small a volume as possible- maybe a 5 gallon bucket? Then loading up that water with something that is toxic to the scuds? But safe for the fish.
For example, would a strong solution of salt kill the scuds? Then rinse the filter media well and put it back on the pond. A minor amount of salt that might stick in there is not a problem to the pond.
Same idea, but hydrogen peroxide? You might have to get the stronger one (not the common 3% that is easily available) Like salt, the last little bit that might remain after a good rinse is not a problem.
Same idea, but a stronger dose of dog and cat wormer? Again, thoroughly rinse until whatever remnant is there is too low to harm the pond.
I would be quite worried about the beneficial bacteria if you did this. I would get a bottle or two of Nitrospira to boost the bacteria population after the treatment.
This has only taken care of them in the filter. If the fish are not eating them in the pond, then they are going to end up right back in the filter pretty fast.