Smart ATO Micro - Automatic Top Off System - AutoAqua Max wall thickness: 1/2 inch (12.7mm) ,Mounts to Most Clear, Tinted or Painted Surfaces Everything you need is included ,Safely keep water & salinity levels (in Marine Aquariums) stable.No moving parts that can fail The siphon break needs to be mounted higher than the water level . Pump needs to be 24" or less distance from height of water level in Aquarium. LED's can cause the Micro Ato to have trouble detecting water level so dont mount sensor close to any bright light source including moon lights, When the alarm is activated check reservoir level, check for bubbles on sensor, move sensor to darker location in sump or aquarium. If the alarm has been on for more than 4 minute please reset unit by unplugging and waiting 10 seconds to re plug it in.