Silviu Man
Member
This is simple. Don't count in kg but in cm (thick) and, based on this, in litters. If you want to use fertil substrate under sand, you need around 1 cm of it, covered with at least 3-4 cm of planting substrate. The purpose of using fertil substrate is that it slow releasing the nutrients in the planting substrate. You also may use universal substrate that contain nutrients but can be also used for planting. If you look over the suppliers recommendations, all of them mention the same way of counting.
See two exemples :
First is a fertil substrate that need to be sealed with a ornamental gravel.
http://tropica.com/en/plant-care/substrate/
Second is an universal substrate.
http://tropica.com/en/plant-care/aquarium-soil/aquarium-soil/
You can see how the calculations are made.
See two exemples :
First is a fertil substrate that need to be sealed with a ornamental gravel.
http://tropica.com/en/plant-care/substrate/
Second is an universal substrate.
http://tropica.com/en/plant-care/aquarium-soil/aquarium-soil/
You can see how the calculations are made.