Tank reference
Innovative Marine NUVO 40
24 × 20 × 16 in
Key stats
Dimensions (L × W × H)
24 × 20 × 16 in
61 × 51 × 41 cm
Volume (raw, outside)
33 US gal
125.8 L · 7680 in³
Water volume (with glass inset)
30 US gal
111.8 L
Manufacturer nominal
40 gal
Differs from raw — manufacturer rounds down for shipping
Footprint
3.33 ft²
480 in²
Filled saltwater weight
380 lb
172 kg · 114 lb/ft² floor
Filled freshwater weight
336 lb
152 kg
Recommended glass (annealed)
10 mm
0.394 in · safety factor 3.8
Heater size (78°F target)
119 W
Redundant pair: 2× 75 W heaters
Substrate (2" sand bed)
47 lb
CaribSea Special Grade · 3 × 20-lb bags
How many gallons is a 24 × 20 × 16 in tank?
A 24 × 20 × 16 in aquarium contains 33 US gallons by outside dimensions. The math:
24 × 20 × 16 = 7680 in³ 7680 ÷ 231 in³/gal = 33.25 US gal 33.25 × 3.785 = 125.8 L
In practice, actual water capacity is 30 gallons after subtracting 0.375" of glass thickness on each side. Manufacturers typically market this as a 40-gallon tank for round-number simplicity.
For a different shape (cylinder, hex, bow-front) or to enter custom dimensions, use the full aquarium volume calculator.
How much does a filled 24 × 20 × 16 in tank weigh?
- Saltwater reef (with ~30 lb live rock + 1" sand bed): 380 lb (172 kg)
- Freshwater (with 20 lb gravel, no rock): 336 lb (152 kg)
- Empty glass only: approximately 63 lb
- Floor load: 114 lb/ft² (saltwater filled)
Floor-load warning: at 114 lb/ft², this tank exceeds the 40 lb/ft² typical residential live-load rating. Place over a load-bearing wall or get a structural assessment before installing upstairs.
Full breakdown including equipment, sump, and custom rock weight: aquarium weight calculator.
Glass thickness for a 24 × 20 × 16 in tank
Using the Wisner hobby formula with a 3.8 safety factor, this tank requires:
- Annealed (regular float) glass: 10 mm minimum (0.394")
- Tempered glass: 5 mm minimum (tempered is ~4× stronger than annealed)
Most commercial tanks at this size ship one thickness step up for additional safety. See the glass thickness calculator for the full formula and Starphire (low-iron) options.
Heater wattage for a 24 × 20 × 16 in tank
In a warm room (~70 °F ambient) targeting 78 °F, this size tank needs about 119 W of heating. The conservative reefkeeping practice is to run two heaters at 75 W each: if one fails stuck-on, the other isn't powerful enough to cook the tank alone; if one fails stuck-off, the remaining one slows the temperature drop while you replace it.
For cold-room or cool-basement adjustments: heater wattage calculator.
How much sand or gravel for a 24 × 20 × 16 in tank?
- 2" sand bed: ~47 lb of CaribSea Special Grade aragonite (3 × 20-lb bags)
- 4" deep sand bed (DSB): ~94 lb
- 1" shallow / aesthetic: ~24 lb
Other substrate brands (Nature's Ocean, Tahitian Moon, Eco-Complete): substrate calculator.
Equipment for this tank
Salt, sand, heater, and light picks sized for a 33-gallon tank. All on Amazon — prices and stock change daily.
Red Sea Coral Pro Salt — 7 kg bucket (55 gal mix)
High-alk, high-Ca reef salt. Spec sheet at 11.5–12.5 dKH.
View on Amazon →
AI Hydra 32HD
Standard SPS-grade fixture. 24×24 in footprint at SPS PAR.
View on Amazon →
Bubble Magus Curve 5 skimmer
Best budget skimmer for tanks up to 80 gal.
View on Amazon →
Cobalt Aquatics Neotherm heater
Most-recommended reef heater. Shatter-resistant.
View on Amazon →
CaribSea Arag-Alive Special Grade reef sand
Live aragonite, no rinse, 2-inch grain. Reef default.
View on Amazon →
Mag-Float aquarium glass cleaner
The hobby standard magnetic algae scraper. Sizes for any tank.
View on Amazon →
Refractometer for saltwater + calibration fluid
Calibrate with 35 ppt fluid monthly. Replaces hydrometers.
View on Amazon →
Salifert KH/Alkalinity test kit
The hobbyist standard for alkalinity testing.
View on Amazon →
Affiliate links. As an Amazon Associate, reefcalcs earns from qualifying purchases.
FAQ
- How many gallons is a 24 × 20 × 16 in tank?
- A 24 × 20 × 16 in aquarium holds approximately 33 US gallons by outside dimensions (125.8 L). After subtracting a standard 0.375" glass thickness on each interior wall, the actual water capacity is about 30 US gallons. Manufacturers commonly market this as a "40-gallon" tank.
- How much does a filled 24 × 20 × 16 in tank weigh?
- A 24 × 20 × 16 in saltwater reef tank with ~30 lb of live rock and a 1" sand bed weighs about 380 lb (172 kg) filled. Freshwater with no rock comes in lighter, around 336 lb. Floor load is roughly 114 lb per square foot — most residential floors are rated for 40 lb/ft² live load, so confirm before placing upstairs.
- What glass thickness do I need for a 24 × 20 × 16 in tank?
- Using the Wisner hobby formula with a 3.8 safety factor, a 24 × 20 × 16 in tank needs at least 10 mm annealed (regular float) glass. Tempered glass can be 5 mm and still meet the same safety margin. This is the calculated minimum — most commercial tanks at this size ship with one step up for safety. See the glass thickness calculator for the full math.
- What size heater for a 24 × 20 × 16 in tank?
- For a tank in a warm room (~70 °F ambient), this size needs roughly 119 W of heating. For redundancy, run two heaters at 75 W each — heaters fail, and a single point of failure on tropical fish or coral is expensive.
- How much sand or substrate for a 24 × 20 × 16 in tank?
- A 2-inch sand bed in this footprint (24" × 20") needs approximately 47 lb of CaribSea Special Grade aragonite, or about 3 20-lb bags. For a deep sand bed at 4 inches, double that.
- Is a 24 × 20 × 16 in tank good for a reef?
- Yes — the 24 × 20 × 16 in footprint is well-suited to a reef tank. The width gives enough front-to-back depth for aquascaping. Tank height is shallow — easy on lighting but limits vertical aquascape.
Run your own numbers
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