force in the middle of the tank 20 to move the debris with water entering the tank 20 in a 4 u2033 pipe and then being exposed to the ambient water with the open top on the trough 36 the water can very quickly mix with the stationary water and lose its velocity in a preferred embodiment in order to keep most of this velocity a top 37 can be positioned on this trough 36 which will help it to hold the water velocity longer in the tank this top 37 can be positioned with a 1 u2033 gap between it and the trough on both sides to allow debris up to 1 u2033 smallest dimension to fall inside the trough or channel 36 in accordance with another preferred embodiment in order to ensure good water flow in the middle the trough cross section can be divided so that there is a lower or distal section that can be fully covered and therefore does not mix with the tank water to the middle section of the tank and then the proximal section can be uncovered and mixed with the slower water in the main section of the trough in case of oversized debris such as for example anything larger than 1 u2033 in accordance with a preferred but not limited to embodiment of the present invention an open.