This high-quality 55-gallon drum is black in color and comes with a pre-drilled cover and bolt ring closure. It is perfect for use as a reservoir for larger hydroponic systems. The pre-drilled holes can be used for the grommets and barbed fittings necessary to outfit the drum with tubing for filling and draining. A larger hole can also be cut in the cover to act as a port for adding nutrients, checking pH, etc. Pair this drum with the Active Aqua Grow Flow accessories (sold separately) to create the most efficient ebb & flow system on the market. With the Grow Flow’s easy-to-program controller unit, you can pretty much "set it and forget it." Have bigger plans? With our convenient Grow Flow Expansion Kits (sold separately) you can connect up to 24 growing modules to a single 5-gallon system – and up to 48 modules with the 2-gallon system.