It ALL starts with what effect the owner is looking for? Is this to be viewed primarily from the upper side of the pool, looking at the overflow as the water “disappears” over the edge? Does the “downhill” view have as great significance? Is a “waterfall” effect, on the downhill side, required? Will the effect be viewed from any upper level rooms? These questions, and others, MUST be answered prior to designing, pricing or building the vanishing edge. In many situations, the only effect required is the overflow effect for people viewing the pool at patio level. In these cases the hydraulic design is much simpler and the material selection for the downhill side less significant. But all of it matters! We need to know what the buyer is expecting as it is not something that can easily be changed later.