Originally Posted by corsair75
I used a bunch of potting soil when I set up my 55 and I'm still paying for it 10 weeks later. I laid down about an inch and a half, and unless I aerate pretty heavily I get ammonia. Almost every problem I've had with the tank can be traced back to the dirt. Too rich, and too much. I run a pair of powerheads with the asperators wide open. I'm also using malaysian trumpet snails to burrow into the substrate and keep it from compacting (as much). It will settle down in time I'm sure, but I'll be measuring that time in months not weeks.
If you are using potting soil, it is better to ensure that it does not have terrestrial fertilizers mixed in it.
These fertilizers release a lot of ammonia when submerged.
Plain soil without fertilizer of any type is a good option.
I had set up a 45g tank last month with plain garden soil and cuttings from my another tank.
It has not presented any problem till now.