Weight of Water
From The Aquarium Wiki
Water weights a remarkable and deceptive amount.
- 1 litre of water weighs 1 kg (2.2 lbs); 1 US gallon weighs 8 pounds.
So a small 25 Litres (6.6 US G.) tank of water weighs 25 Kg or 55 lbs, and that's before you take into account the weight of the tank, ornaments and equipment you put in it.
In a typical 4 foot tank, say ~250 Litres (66 US G.), that water will weigh in at 250Kg or 555 lbs (39 stone)!
This is why you must be careful that the piece of furniture you place the tank upon can take the weight. With large tanks you must also ensure that the floor can take the weight.
- Add extra legs from a DIY store to support the weight.
- Position a large tank across several floor joists (the support beams under the flooring) rather than along them.
- Ensure any floor is level, especially older floors. Large tanks on unlevel floors can put extra strain on the seams of the tank and could cause cracks and leaks.