Aquarium Calculators
Quick, accurate tools for every aquarium keeper — from sizing your tank to dialing in your salt mix.
Aquarium Volume Calculator
Find the true water volume of rectangle, cylinder, bowfront, and hexagon tanks.
Fish Stocking Level Calculator
Check whether your tank can comfortably support your planned fish load.
Add your fish (adult size):
The 1 inch per gallon rule is a rough guide for small community fish. Messy fish, large species, and reef tanks require more conservative stocking.
Heater Wattage Calculator
Determine the right heater size based on your tank volume and room temperature.
Water Change Volume Calculator
Know exactly how many gallons to remove and replace for any percentage water change.
Salt Mix Calculator
Calculate how much salt to add to reach your target specific gravity for saltwater and reef tanks.
Always mix salt in a separate container and verify with a refractometer before adding to your tank. Values are estimates — follow your salt manufacturer's instructions.
Alkalinity (dKH) Dose Calculator
Calculate how much two-part or kalkwasser to add to raise your reef tank's alkalinity to target.
Raise alkalinity slowly — no more than 1–2 dKH per day to avoid shocking corals. Test before and after dosing.
Calcium & Magnesium Dose Calculator
Find the exact dose of calcium chloride or magnesium sulfate needed to hit your target parameters.
Typical: 380–420 ppm
Reef target: 420–450 ppm
Always dose slowly and re-test after 24 hours. Do not dose calcium and alkalinity supplements simultaneously.
Need professional help with your aquarium?
Aquarium Xpress provides expert maintenance, installation, and consultation services across Central Pennsylvania.