Free aquarium filter calculator. Calculate required flow rate in GPH/LPH based on tank volume and livestock type. Covers planted, community, and turtle tanks.
Filtration is the life support system of any aquarium, responsible for removing physical debris, neutralizing toxic ammonia and nitrites through biological action, and eliminating chemical impurities. Selecting a filter with the correct flow rate is essential to ensure that the entire water volume is processed frequently enough to maintain pristine conditions. This calculator helps you determine the ideal turnover rate based on your specific tank type and livestock requirements.
Our filter calculator uses the concept of "Turnover Rate," which is the number of times the total water volume passes through the filter per hour (GPH or LPH). We provide tailored recommendations: 4x turnover for planted tanks to preserve CO2, 6x for standard community tanks, and up to 10x for high-waste species like goldfish or large cichlids. The tool calculates the required minimum flow rate based on your net water volume, ensuring your biological filter media has constant access to oxygenated water and waste products.
Enter your tank volume and tank type to calculate required filter flow rate (LPH/GPH). Different turnover rates apply for planted tanks, small fish, large fish, and turtles.
Actual filter flow may be lower than rated flow due to media resistance. Choose a filter with a rated flow 20–30% higher than the calculated value.
New tanks need 4–6 weeks to establish a stable nitrogen cycle. During this period, reduce feeding and monitor water parameters closely.
Filter flow rate (GPH or LPH) is how much water the filter processes per hour. A general rule is 4-10 times the tank volume per hour. For example, a 50-gallon tank needs 200-500 GPH filtration.
Heavily stocked tanks need more filtration (8-10x tank volume/hour) because fish produce more waste. Lightly stocked tanks need less (4-6x). Planted tanks may need less filtration due to plant nutrient uptake.
This calculator uses standard guidelines for filter sizing. Actual needs depend on fish species, feeding amount, and tank maintenance. For precise sizing, consult an aquarium specialist.
Main types are mechanical (removes particles), biological (converts waste), and chemical (removes dissolved substances). Most filters combine all three. Choose based on your tank type and fish species.
Clean mechanical filter media every 1-2 weeks. Rinse in old tank water to preserve beneficial bacteria. Replace chemical media monthly. Never clean biological media with tap water. Follow manufacturer instructions.