Aquarium Filter Size Calculator
Aquarium Filter Size
Calculate the right filter for your aquarium
gallons
Formula
Required GPH = Tank Volume (gallons) x Turnover Rate (4-8x per hour)
Frequently Asked Questions
How do I calculate filter flow rate?
Multiply your tank volume by the desired turnover rate. For most freshwater tanks, you want the entire water volume to pass through the filter 4-6 times per hour. A 30-gallon tank needs 120-180 GPH (gallons per hour) of filtration.
Which is better: HOB or canister filter?
Hang-on-Back (HOB) filters are easier to maintain and more affordable, ideal for tanks under 55 gallons. Canister filters offer more media capacity, higher flow rates, and quieter operation, making them better for larger tanks or heavily stocked setups.
How often should I clean my aquarium filter?
Rinse mechanical filter media every 2-4 weeks in old tank water (never tap water, which kills beneficial bacteria). Replace chemical media (carbon) monthly. Biological media should rarely be replaced - only rinse gently if flow is severely reduced.
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