Any Organic Potting Soil will work. You can't use the Miracle Grow Soil you have unless it is Organic. I use Just Natural Organic Potting Soil from Lowes in my tanks. I usually use an 1-1/2" of Organic soil to 1-1/2" of cap. I use Eco-complete for my cap. Also the more plants you use, especially fast growing plants like water sprite, wisteria, and fast growing stem plants the faster your tank cycles since these plants use ammonia and nitrates. Planting 80% or more of the tank in the beginning is best for a quick cycle. I did this with my dirted 220g and was cycled in 10 days. Cycling time varies.