🐠 Aquarium
Aquarium Filter Size Calculator
Estimate filter GPH from tank size and stocking so water turns over enough times per hour.
Fill in a few details and watch the numbers wag into place.
Friendly reminder: ask your vet. These tools are smart guesses, not medical advice. When in doubt, call the professionals who know your pet best.
Frequently asked questions
- What does filter size mean in this calculator?
- Enter tank gallons and stocking level. The tool recommends flow rate or filter model class rated for that volume, often with headroom for moderate bioload.
- Why is my filter rated for more gallons than my tank?
- Manufacturers often label filters for lightly stocked tanks. Heavy fish load or messy species may need the next size up for clear water and ammonia control.
- Can I use sponge filters with this recommendation?
- Sponge filters suit breeding or shrimp tanks with lower flow. Match air pump and sponge capacity to gallons; the same bioload rules apply.
- When are water tests more important than filter labels?
- If ammonia or nitrite ever read above zero with fish present, upgrade filtration or reduce stocking and increase water changes. A local fish vet or store can help troubleshoot cycles.