How dose a auto top off work?

[chris124]

How dose a auto top off work and are they safe? Pictures would be nice. Thanks.

 

[EW_Fish]

Pretty much there is a float valve in your setup and when your water evaporates the tank level lowers causing the float to kick your pump on to replenish the water in your tank. You want to use rodi water because the salt does not evaporate it helps keep your salinity stable also
Auto Top Off (ATO) Systems In Saltwater Aquariums - YouTube

JBJ ATO Auto Top Off System Setup - YouTube