This is our drainage layer of choice! Hydroton are expanded clay balls that absorb and release water evenly, promote high levels / surface area of aerobic bacteria growth (the good stuff!), and provide an excellent negative space to trap water in the drainage layer. This is the same material many hydroponic shops use for growing plants.
Pour in the recommended bags of hydroballs for your setup (2-3 inches)
10 gallon - 2 bags
12x12 - 1.5-2 bags
20 gallon - 3-4 bags
18x18 - 3-4 bags
40 gallon breeder - 5-6 bags
24x18 - 4-5 bags
36x18 - 5-6 bags
55 gallon - 6-7 bags