How to Determine the Amount of Substrate Needed for an Aquarium

Having a pleasant looking substrate is an important part of the beauty of aquarium decorating. In addition to being decorative, substrate is a very important part of the biological filtration in your aquarium. Aquarium SubstrateTo ensure that the substrate has adequate surface area to assist with biological filtration, you must know how much substrate to use. A general rule of thumb is to use between 1 and 2 pounds of substrate per gallon of water, but a more accurate rule is to have a layer of one to two inches when the substrate is placed into the aquarium. The problem with the second rule is that it can be difficult to calculate the amount of pounds of substrate required to produce 1 to 2 inches. We have compiled a table to help you estimate the pounds of substrate you will need to purchase to have one or two inches of substrate.


Many aquarists will recommend that you add several extra pounds to your estimate to keep aside. This will help replace any substrate lost over time by water changes or cleanings. Also, extra substrate can be used to make diy aquarium decorations. It is really nice to have extra substrate that matches existing substrate when making plant holding bases or aquarium caves. If you would like to get a more accurate measurement for your tank, please feel free to use our online aquarium substrate calculator.


If you have a standard size tank then you can use this table to help you estimate the substrate needed. These values should give you about one inch of substrate. If you would like more than an inch just multiple the pounds by number of inches.


Aquarium Size Pounds of Substrate
10 10
15/20H 15
20L/29/40H 29
50/65 (4 foot) 50
40L/55 (4 foot) 55
75/90 (4 foot) 80
120 (6 foot) 120
125/50 (6 foot) 125
180 (6 foot) 180

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