have been doing some research about using worm castings and even soil in planted aquariums I have a bag of worm castings and plan on attempting to use it with sand on my 30 gal project. does anyone have experience with worm castings or any kind of soil mix. I also have PRO-MIX a soilless mixture. IM just curious about using them for a bottom layer then worm castings as a middle and sand on top. let me know would love input.