The part about the app showing nothing until you opened it manually is what gets me. I used to figure these gadgets were just backup, a nice extra on top of common sense, so if one missed a alert here or there it was no big deal. Then my cousin had a sump pump setup that did the same thing, silent the whole night while water crept across her floor. That changed my mind real quick. A leak sensor that does not wake you up is worse than not having one, because you trust it and stop checking. Now I test mine on purpose every couple months with a wet rag, and if it stays quiet I toss it.