You’ll find everything from power filters to canister filters to modular filters on our site. Plus, we carry under-gravel filters, sponge filters, sump filters, and fluidized bed filters to accommodate any application or setup. Each one provides high-quality filtration to ensure the best water quality and clarity for your fish. Top Fin® Undergravel Filter at PetSmart. Shop all fish filters online. ... Gravel & Substrate Heating & Lighting Filters & Pumps Maintenance & Repair Starter Kits ...

Compare that with the 2 stages of an undergravel filter (when its not being stirred up). I think the decision is pretty easy. A canister filter pulls the water out and filters it in 4 stages and an undergravel filter sucks the waste downwards and lets it rot at the bottom when its not being messed up by your turtles. These filters are placed inside the aquarium and allow you to locate your aquarium very close to adjacent walls to save space. Undergravel Filters As their name suggests, these filters are placed underneath a layer of aquarium gravel. These filters move water through the gravel to create conditions favorable for biological filtration.