Aquarium Filters Guides, Reviews & Setup
Buying guides, reviews, and setup instructions for freshwater filters and reef protein skimmers. Find the right filter for your tank size and setup.
Every aquarium needs biological, mechanical, and chemical filtration. The right filter depends on tank size, livestock, and whether you're running a freshwater or saltwater setup. A filter rated for your exact tank size will be undersized in practice — choose a filter rated for 1.5 to 2 times your tank volume for the best results.
The guides below cover every filter type from hang-on-back and canister filters for freshwater tanks to protein skimmers for reef aquariums. Each guide includes product reviews, setup instructions, and sizing recommendations.
Which Filter Type Do You Need?
Five main categories, each suited to different tank sizes and setups.
Sponge Filter
Gentle flow for tanks under 20 gallons. Air-driven, safe for fry and shrimp. Doubles as a grazing surface for biofilm. Cheapest to buy and run.
Internal Filter
Compact and submersible for nano tanks. Sits inside the tank, fully underwater. Good for hospital tanks and small setups where external space is limited.
HOB Filter
Most popular filter for tanks up to 55 gallons. Hangs on the tank rim, easy to access and maintain. Quick cleanings mean it actually gets done regularly.
Canister Filter
Most media capacity and customization for any tank size. Sits below the tank in the cabinet. Supports spray bars, inline CO2, and heaters. The go-to for planted tanks and tanks over 55 gallons.
Protein Skimmer
Essential for saltwater reef tanks. Uses foam fractionation to strip dissolved organics before they break down into nitrate. Not used in freshwater.
Know what you need? Jump to freshwater filter guides or protein skimmer guides below.
Freshwater Filters
Buying guides, comparisons, and how-to guides for HOB, canister, sponge, and internal filters.
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Best Aquarium Filters 2026: Top Picks for Every Tank Size
The best aquarium filter for every tank size, from nano setups to 100+ gallon tanks. Two picks per size range — jump to your tank size and find the right filter in under a minute.
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Best Canister Filters for Aquariums: 5 Filters Compared
We compared the Fluval FX4, OASE BioMaster Thermo, Fluval 407, SunSun HW-302, and PondForse to find the best canister filter for every tank size and budget. Detailed specs, pros and cons, and a complete buying guide.
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Best Aquarium Filters for Large Tanks (55+ Gallons) 2026
The best aquarium filters for large tanks reviewed and compared. Canister and power filters for 55-250+ gallon aquariums including Fluval FX4, OASE BioMaster, Fluval 407, and more.
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Best Biological Filter Media: Guide & Reviews (2026)
Find the best biological filter media for your aquarium. Reviews of ceramic rings, sintered glass, and pumice media to support beneficial bacteria colonies.
Read GuideSetup & Maintenance
Protein Skimmers
Reviews, sizing guides, and setup instructions for reef tank protein skimmers.
Best HOB Protein Skimmer Reviews: Top 5 Hang-On-Back Models
Comprehensive reviews of the best hang-on-back protein skimmers for reef tanks. Compare top HOB skimmers from Coralife, Reef Octopus, IOAOI, and Marine Color for tanks up to 105 gallons.
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Best Nano Protein Skimmer: Top Picks for Small Reef Tanks
Find the best nano protein skimmer for reef tanks under 35 gallons. Reviews of the NF-1, ESHOPPS Nano, and Hydor SlimSkim with buying guide and setup tips.
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Best Protein Skimmer for 200 Gallon Tank: Top Picks Compared
Honest recommendations for the best protein skimmers for 200-gallon reef tanks. Community-vetted picks from Reef Octopus, IceCap, Simplicity, and Tunze with detailed reviews.
Read GuideLearn & Setup
Related Equipment Guides
Filters are one piece of the puzzle. These guides cover the rest.
Heaters & Chillers
Reviews and sizing guides for aquarium heaters and temperature controllers.
Aquarium Lighting
LED light reviews for planted tanks, reef tanks, and freshwater aquariums.
Test Kits
Liquid test kits and monitors for ammonia, nitrite, nitrate, pH, and more.