1gallon Lava rock inconclate with mycorrihizl this is pure stuff not the cat litter some are selling now, trace elements.azomite, dolomite, pot ash and earth worm castings. Natural water Filter Aquascape Substrate/ works great in hydro media. Works great in auqaponics, even great as part of your soil mix helps with getting oxygon too the roots and filled with micro nutes. You could put in your fish tank and the plants and the fish get more of what they need. Great to cycle through aquaponics unit.