Aquarium Gravel Calculator: How Much Substrate Do I Need?

🐟 Aquarium Gravel Calculator

Calculate the exact amount of substrate your fish tank needs by weight and volume

Quick Presets
📐 Tank Details
🧱 Substrate Specs At A Glance
📊 Substrate Comparison Table
SubstrateDensity (g/cm³)Grain SizeBest For
Standard Gravel1.503–5 mmGeneral community tanks
Aquarium Sand1.600.5–2 mmBottom dwellers, Corydoras
Seachem Flourite1.302–7 mmPlanted tanks, root feeders
Eco-Complete1.201–5 mmPlanted tanks, no-rinse setup
ADA Amazonia Soil1.102–5 mmHigh-tech planted, shrimp
Pea Gravel1.556–12 mmGoldfish, large cichlids
Crushed Coral1.452–6 mmAfrican cichlids, high pH
Pool Filter Sand1.580.4–0.8 mmBudget planted, Corydoras
🏠 Common Tank Sizes Reference
TankDimensions (L×W×H in)VolumeGravel at 2 in Depth
5 Gallon16 × 8 × 105 gal / 19 L10 lbs (4.5 kg)
10 Gallon20 × 10 × 1210 gal / 38 L15 lbs (6.8 kg)
20 Long30 × 12 × 1220 gal / 76 L27 lbs (12.3 kg)
29 Gallon30 × 12 × 1829 gal / 110 L27 lbs (12.3 kg)
40 Breeder36 × 18 × 1640 gal / 151 L49 lbs (22.2 kg)
55 Gallon48 × 13 × 2155 gal / 208 L47 lbs (21.3 kg)
75 Gallon48 × 18 × 2175 gal / 284 L65 lbs (29.5 kg)
125 Gallon72 × 18 × 21125 gal / 473 L98 lbs (44.5 kg)
📏 Recommended Depth by Purpose
PurposeDepth (in)Depth (cm)Notes
Fish-only community1.5 – 23.8 – 5.1Enough for biological filtration
Low-tech planted2 – 35.1 – 7.6Sufficient for easy root plants
High-tech planted3 – 47.6 – 10.2Deep roots, carpet plants
Under-gravel filter2.5 – 36.4 – 7.6Even depth is critical
Cichlid / digging fish2 – 35.1 – 7.6Heavier substrate resists digging
Shrimp breeding1.5 – 2.53.8 – 6.4Active buffering soil preferred
📝 Substrate Weight Per Gallon of Tank Floor
SubstrateWeight at 1 in Depth (lbs/gal floor)Weight at 2 in Depth (lbs/gal floor)Weight at 3 in Depth (lbs/gal floor)
Standard Gravel6.212.518.7
Aquarium Sand6.713.320.0
Flourite5.410.816.2
Eco-Complete5.010.015.0
ADA Amazonia4.69.113.7
Pea Gravel6.512.919.4
Crushed Coral6.012.118.1
Pool Filter Sand6.613.119.7
💡 Tip – Measure Inside Dimensions: Always measure the inside of your tank, not the outside. Glass thickness adds 0.25–0.5 inches (6–13 mm) per side. On a 10-gallon tank, this can change your substrate calculation by over 10%.
💡 Tip – Sloped Substrates for Natural Look: For a natural aquascape, make the back 1.5× to 2× the front depth. Select the +25% Sloped Aquascape adjustment to compensate. Slopes create visual depth and help debris collect at the front for easier cleaning.

aquarium gravel does much more than simply sit at the bottom of the tank. It breaks the solid waste and uneaten food that slowly sinks, thus stops the forming of thick buildup. Such buildup can hold useful bacteria that truly helps.

Those bacteria break down the fish waste and help to control the levels of nitrate and nitrite in low values. That helps with the health of the fish. A bed from little grains of gravel provides a large surface for the growth of those bacteria.

How to Choose and Care for Aquarium Gravel

gravel especially stops food, waste and other trash from floating freely through the whole tank. Because of that you need fewer water changes although one must regularly clean it.

The choice between sand and gravel depends mainly on the species of fish and plants in the tank. Some fish dig in the soil, and sharp bits of gravel can injure their mouths or whiskers. Sand is more smooth and tender, so it allows bottom fish, like the cory fish, to naturally dig and sift.

On the other hand, gravel is easier to take care of and it backs good bacterial growth. During cleaning, sand commonly clogs the vacuum tubes, what truly upsets.

Natural gravel works well for planted tanks, just like special species with rounded bits, designed for African cichlids, that helps to keep the water chemistry healthy. Gravel comes in various forms, sizes and colors, from natural shades to shining painted versions. Natural gravel with brown and gray tones gives a softer, calm look, that contrasts well with the plants.

By layering little natural grains below and bigger ones up you can copy a natural riverbed. Adding a black background in the tank does make everything look more alive.

Painted or colored gravel can lose its shade over time, becoming white or gray. The dye from such gravel can also come out and color the water, no matter how many times you wash it. Some cheap gravel from home stores works well, but it commonly has quite a lot of big grains.

Pea gravel from a garden store commonly costs very little, sometimes around five dollars for a fifty pound bag, however such big gravel does not work for aquariums, because the food simply sits stripped up.

For planted tanks, half inch or more gravel provides space for the roots to spread. The general rule is one to too pounds of gravel per gallon of water. Aquarium plants can grow in average gravel without separate soil, if they receive enough light.

Before adding fresh gravel, you must rinse it many times. Many folks rinse it over and over, because there is no such thing as too much rinsing. It is alsofine to run the tank without gravel, if the bare bottom looks good.

Aquarium Gravel Calculator: How Much Substrate Do I Need?

Author

  • Ronan Granger

    Hi, I am Ronan Granger, the owner of AquaJocund.com! At AquaJocund, I’m thrilled to take you on a captivating and immersive journey through the wondrous realm of aquariums and aquatic life.

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