Aquatop 3-Stage Canister Filter

The AQUATOP CF MKII Series Canister Filter delivers premium, multi-stage water filtration for fresh and saltwater aquariums — at a price that defies its performance. Built around a whisper-quiet pump and an innovative dual-priming system, the CF MKII line handles mechanical, biological, and chemical filtration in one sleek, gray-enclosure unit. Available in three sizes to match tanks from 20 gallons up to 175 gallons, each variant ships with all plumbing hardware, filter media, and everything needed for a same-day install.

How It Works

Unfiltered aquarium water is drawn into the canister and — on UV-equipped models — passes directly over the integrated UV sterilizer lamp before flowing downward through the vertical intake stack. Water then travels up through each filtration media compartment in sequence — bottom to top — before returning clean to the aquarium. This bottom-up flow path ensures every drop of water contacts the full filter media stack for maximum efficiency.

Features — All Variants

Choose Your Size — Variant Comparison

Select a variant in the tab section below for the full individual spec sheet.

Detailed Variant Specifications

Click a model below to view its full specification sheet.

Which Size Is Right for You?

CF-300MKII — Best for tanks from 20–75 gallons where budget is the priority and UV sterilization is not required. Ideal for community freshwater tanks, planted aquariums, and smaller reef setups where manual water changes are routine.

CF-400UVMKII — The sweet spot for 75–125 gallon setups. The addition of the 9W UV sterilizer makes a meaningful difference in disease prevention and algae control in moderately stocked tanks. Our most popular CF MKII model.

CF-500UVMKII — Built for serious hobbyists with large, heavily stocked, or high-bioload systems up to 175 gallons. The extra media compartment and 525 GPH flow rate give you the headroom you need for demanding aquariums.

Customizing Your Filtration

All CF MKII models ship with mechanical media pre-installed, but the open-tray design means you're in full control of your filtration setup. A recommended stack for most aquariums:

Bottom compartment: Coarse sponge (included) for pre-filtration and initial mechanical capture.
Middle compartment(s): Ceramic rings or bio-balls (sold separately) for biological colonization — this is where beneficial bacteria live.
Top compartment: Fine filter pads (included) for final polishing; add activated carbon (sold separately) to remove odors, tannins, and chemical impurities.

What's in the Box

All variants include the following:

CF MKII Canister Filter Unit · All required plumbing hoses & fittings · Secure-mount hose connectors · Fine filter pads (white) · Coarse filter sponge (blue) · Surface skimmer attachment · Vortex prime button · Traditional priming pump · Instruction manual

CF-400UVMKII also includes: Premium Activated Carbon + Bio-Balls. Additional media (ceramic rings, bio-balls, activated carbon) available separately. UV replacement bulb (R9WUV-G2) sold separately for UV-equipped models.