Use a pole and plumb bob for hard-to-reach distances
To measure from the hopper edge to a side wall, feed the plumb bob string through the hole at the end of the skimmer pole. Lay the pole on the deck at the deep end and extend it perpendicular to the end of the pool. When the plumb bob is at the point where the floor and wall meet, mark the pole at the coping edge. Place the pole on the deck and measure from that mark to the string hole.