We are putting a fence around the yard... another mesh fence around the pool... chime on house door when opened. Chime on pool gate when opened... but I'd also like to have a subsurface alarm in the pool. I read a CPSC document from 2000 that said the subsurface alarms worked the best, but I could not read the label on the one they said worked best... and I am sure it has changed since 2000. As my 4th layer of protection, can anyone tell me what the best subsurface alarm is? Preferably one that has a contact closure I can tie into my automation system to have alarm go off in house also.