Do you have any problems with your filter ? Does your output flow seems ok ? Do you have any ammonia nitrites in your tank ? Is it making noise ? Is it leaking ?
If not, then your filter is okai, the filter job is to keep water clear and convert ammonia to nitrites then to nitrates.
If the hose get clugged, I would change them, as they very hard to clean. You must rinse the bio part with tank water, so the bacterias will have maximum surface to contact with water. You can rinse the filter pads under tap water, it will bleach them a bit and give them their original white color.
So to know if it working in top condition, make ammonia/nitrites test, and you'll know if the main part is working properly. You should get 0ppm both readings.
You can measure the flow with buck and water and compare your data with the compagny rating. Usually compagny overrate their products, so a product rated 200GPH can be 140GPH new, and without filters mass. You can go the classic way, just put your hand under the output flow, and if it make you happy, then it's working properly.
