A distributor system for uniformly directing vapor and liquid across the surface of a fixed bed of solids in a downflow reactor comprising a distributor tray, and a plurality of open-ended downpipes extending through the tray. A first array of the downpipes has a plurality of vertically spaced elevations of holes above the level of the tray. A second array of the downpipes has at least one elevation of holes at substantially the same height above the level of the tray as one of the upper elevations of holes in the first array of the downpipes. But, the second array has no elevation of holes corresponding to the lowermost elevation of holes, and possibly other lower elevations of holes, in the first array of downpipes. The absence of the lowermost holes in the second array of downpipes causes the liquid flow rate through the distributor tray at a given liquid height to be reduced when that liquid height falls below the elevation of the holes second from the bottom in the first array. This maximizes the liquid height above the lowermost holes, preserving good distribution even when the distributor is subject to variations in level from one point to another.