Unipac are a leading supplier for aquarium gravel, sand and decor, Astral mix is from the steller stone range which is a haerd wering epoxy coated gravel. These coated gravel are far superior than powder coated gravels which can loose colour through maintenance quicker.
How much gravel do i need in my tank?
As a very rough guide for every 1ft length of Aquarium approx 10Kg of sand or gravel is required. This will give approx depth of 1.5" or 40mm
The calculation is as follows
Length x Width divided by 10. This then gives the weight required in Lbs. To convert this to KG just divide the answer by 2.2
For example on a 4ft x 1.5ft long tank
48(inches) x 18(inches) = 864 divided by 10 = 86.4(lbs) divide again by 2.2 = 39.27KG