Construction Sand VS Silica Sand
Why do we discourage the use of ordinary sand as your filter sand? Ordinary sand also known as manufactured sand, construction sand or bistay sand (if you are from the Philippines) is a grey colored sand, it is an artificial sand produced from crushing hard stones into small sand sized angular shaped particles, washed and finely graded to be used as construction aggregate. It has a low silica content and never meant to be used as filter sand.
The natural silica filtration grade sands have a sub-angular to rounded shape, making them an ideal filtration media to capture suspended solids in water. Due to the high silica content, the sand is extremely durable and hard-wearing, allowing it to be precisely graded to facilitate efficient filtering.