Originally Posted by jeffaquarius
Now I'm beginning to understand why a thicker substrate is more desirable.
Yes, if you want to rely/utilize the denitrification process in nitrate removal. Or you can rely on the simple fertilizer/plant growth method where little bits of algae grow and are eaten by herbivore invertebrates and fish and the poop is skimmed out. Or algae scrubbers and macro algaes are manually removed.
Then there is no risk of sulphates entering the denitrification process and creating deadly H2S gas.