If PP is your only available option, I have treated my ponds many times with 2.0PPM PP with almost constant increases due to degradation, using test strips to evaluate concentrations. I have never turned off my filters and have not found that the filters were severely impacted, as measured by no increase in ammonia, or nitrites. The fact that it is burning up stuff in the filter means the concentration decays faster, but staying on top of it, you can maintain the concentration needed to treat not only the pond and fish, but also the filters. There are better treatments, but as I stated, if you have no other available options it will work.
Zone 7 A/B
Keep your words sweet. You never know when you may have to eat them.
Richard