I have 2 200B filters running on 2 separate tanks currently. (I think that's the right model number)
One is planted with the wifes fancy pearl scale GF, a male beta, 4" blue Gourami, a mating pair of Cory cats, an african dwarf frog and a few baby japanese trapdoor snails.
The other has one juvenile fancy GF, Dojo loach a pair of peacock eels, a small pleco, and again a few small JTDsnails.
The planted tank has a small basket I placed the inlet into, this unit I have to clean about 3 times a week to keep the flow up. There are 2 problems, one, plants get sucked into the filters impellers causing obstructions. 2, snails small enough to get into my intake basket will be sucked into the Impellers cage slowing down the flow. These are removed and placed into another tank with a standard intake.
The other tank has hornwart and a normal caged inlet, this gets a new filter when its wheel slows to a crawl, as it happens so infrequently.
So it really depends on the load each filter experiences. I have used a filter sock that clogs every other day on the planted tank and I also tried the sponge on the inlet, neither provided enough of a window to spead out cleaning to the weekly water change intervals. BUT everytime I have cleared obstructions from the intake tube and cleared any vegitation my wifes fish has sent into my filter, the wheel spins like new. I clean the cartridge every 3rd day, by running under water and scrubbing the gunk off with a brush, and flow is normal.
If your flow is not enough to spin the wheel, there is an obstruction. Period.
Pull your filter inlet off and clean it out, including the frame that holds the impeller in place, remove anything that might have wrapped itself around the impeller shaft, you will have to remove the frame that holds the impeller in place to do so. Also try the block of foam over the intake, this will have to be cleaned periodically, especially if sand is used as a substrate.
