The power filter, is one of the fundamentals of the DSR method.
It is just a a name for a strong pump with filter wool on the intake.
It removes annoying small particles and clouding from the water, which prevent detritus from settling in  low flow area. It’s essential to manage an optimal flow ( not necessary strong), to keep the dirt into suspension, so it can be picked up by the power filter

A optimal working power filter can produce a crystal clear result, without any additional filtering media. A power filter require a powerful pump
Minimum is capacity required:
– 1000l/h for tanks up to 200l ……….. (H.max > 1,25m)
– 2400-3000l/h for tanks up to 1000l (H.max >  2m)

examples of  power filters

A power filter can also be applied on the intake of the main return pump.

Although less efficient and more power consuming, a power filter can also be placed in the sump. Rating 1200-3000l/h (~1/3 of main pump)

Optimal performance is reach by replacing filterwool every 2-3 days. Use alternating  flow and occasionally stir up the sandbed if it takes longer for the filterwool to get saturated. Don’t use the filterwool longer than 5 days, because it will have an ill effect on the corals. A well maintained system can go without a powerfilter for a few weeks. i.e. during vacation