Although not quite a leak locating tool, a regular towel is what we used to damm up the slot drain to locate the leak. Slot drains are not very wide and it’s hard to locate a leak when there is no water pooling in the drain. By damming up the slot drain with two ordinary towels, we were able to keep enough water in the drain to locate the leak. The incredibly sensitive PoolScope and creative thinking was what we used to locate a leak in this slot drain. Get the equipment that finds leaks fast in vinyl OR concrete swimming pools, the Pro Kit, Pro Complete and VILO Vinyl Liner Swimming Pool Leak Detection Kits.