Planted Tank Substrate. The Substrate in your Planted Aquarium is the single most important part of your aquarium. (more than lighting in my opinion) This is how to setup your Planted Aquarium with a Substrate that will feed your aquarium plants. I have the LARGEST Aquarium YouTube Channel in the United States because of how many people I have helped setup a their planted aquarium substrate with dirt under the gravel as their substrate layer. This playlist has almost everything you can ever want to know about planting a planted tank with Dirt. This is how you create the ideal substrate for your planted tank. I feature a tank where I used half of the substrate as dirt and the other half of the aquarium substrate as gravel. The "50/50 tank" if you will. You can see why you should use soil as your planted aquarium substrate by just looking at the difference between the growth in the two sides of this tank. less