Last updated: March 2, 2026

Understanding Aquarium Tank Sizing and Equipment

Formula

Aquarium volume is calculated by multiplying length x width x height (in inches) and dividing by 231 to convert cubic inches to US gallons. This is essential for determining fish capacity, heater wattage, and filter flow rate.

A general rule is 5 watts of heater per gallon of water, and a filter that processes 4-6 times the tank volume per hour. Larger tanks are actually easier to maintain since water parameters change more slowly.

Common use cases:

  • Setting up a new aquarium
  • Equipment sizing and selection
  • Estimating water weight for floor support

Frequently Asked Questions

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