I have a bag of ADA Amazonia Aquasoil 9kg and just bought a 20kg box of Pisces New Zealand Iron Sand. I am thinking about mixing them both in a completely new cube tank.
First i'd like to know, it is ok for me to mix both of them? the amazonia seems to be a bit more thick grain, while the pisces Iron Sand is a very fine black sand. Both look amazing, however i am not sure if its any problem in mixing them, or if there's a particular order for me to put them. Like (the sand on bottom and the soil on top, or opposite, or all mixed.
I have read some stuff about compressed substrate or gravel substrate creating some spots with either too much ammonia or lack of oxygen and i am not sure i understood.
And last, in your opinion what would look better and be more prolific for the plants i will keep?
The aquarium is a 90 gallon cube tank, the sum of the substrates should create a depth of 2 inches according to some calculators online... or i could even have 1 inch at the front and a bit deeper in the back.