extended sidewall 62 which extends from a perimeter 60 of the enclosed bottom 32 terminating in a bottom rim 48 the bottom rim 48 includes an inner concentric ledge 50 pads 52 extend from ledge 50 and are suitable to engage with the top rim 36 and perimeter edge 58 of another tank on which it may be stacked first opening 64 and second opening 66 are formed in the extended sidewall 62 and are sized and shaped to conform with an external shape of trough 16 interior region 68 is defined by enclosed bottom 32 and extended sidewall 62 within the interior 68 and aligned with first opening 64 is drain 72 integrated with fluid outlet 20 the drain 72 may by way of example include a hex insert 74 molded congruent with the tank 14 a round threaded hole 76 is formed in the hex insert 74 the threaded hole 74 is adapted to receive drain plug 78 having an orifice 80 extending therethrough the diameter of the orifice may be increased or decreased to control the rate of fluid draining out of the tank 14 through the drain 72 and orifice 80 the plug 78 may include a shape 82 such as a square to provide a gripping shape for a tool to rotate and tighten the plug 78 within the hole 76 alternatively a faucet or valve may be coupled to the threaded.