Substrate: How Much Do You Need?
Drs. Foster & Smith Educational Staff

Variety of Aquarium Substrate Determining how much substrate to buy for your new aquarium depends on the size and shape of your tank, as well as the depth of the substrate bed you wish to achieve. Other factors include the type of aquascaping structure you're planning, and the grain size of the manufacturer's substrate of choice.

While this may sound complicated, don't worry - you won't need to be an algebra whiz to get started!

The simplest rule of thumb to use is to plan 1 lb of substrate per gallon to achieve a 1" bed. Or 2 lbs per gallon for a 2" bed. Since aquariums come in a variety of shapes, tall or long, we recommend the following guide for your reference:

Aquarium Size* (gallons) #s of Substrate   Aquarium Size* (gallons) #s of Substrate
10 10 - 20   15/20H 15 - 30
20L/29/37 29 - 58   50/65 50 - 100
40L/55 55 - 110   75/90 75 - 150
120 120 - 240   125/150 125 - 250
180 180 - 360      

*Does not apply to bow, hex, or corner-shaped aquariums.

Many hobbyists will tell you it's always safer to get more substrate than you think you may need, because then you'll always have some on hand for future renovations or additional setups. Using this simple advice, we hope we've helped you get to the bottom of your substrate needs!