Calculate Tank Volumes,
Healthy Water Chemistry.
Free aquarium calculators: tank volume and weight, stocking levels, heater and filter sizing, water change amounts, and dosing math.
True Net Water Volume
Deducts 10–15% water displacement for gravel substrate and driftwood hardscape.
Biological Stocking Limits
Biochemical oxygen demand sizing beyond crude rules-of-thumb.
Heater Wattage Sizing
3–5 watts per gallon to maintain steady 78°F tropical baselines.
AquariumMath Tools
Aquarium Volume & Weight Calculator
True water volume and total weight — from tank dimensions, minus substrate, decor, and displacement.
Fish Stocking Calculator
Bioload-aware stocking check — fish count and size against real gallons, with the surface-area refinement.
Aquarium Heater Calculator
Heater wattage by real gallons and the temperature gap — with the two-heater rule for big tanks.
Water Change Calculator
Change amounts and dilution math — how much to change to hit a nitrate target, and the refill temperature check.
Practical Guides & Best Practices
The nitrogen cycle: the only chemistry lesson fishkeeping requires
Ammonia to nitrite to nitrate, the bacteria that do the work, and why new tanks kill fish.
The real cost of a tank: what the box price hides
Equipment, livestock, electricity, and the monthly reality behind the "starter tank" sticker.
12 mistakes people make with aquarium keeping
The recurring errors we see in aquarium keeping — what causes each one, and the habit that prevents it.