On the left is a 75 gallon fresh water holding tank.
On the right is a 175 gallon salt water holding tank.
In the middle is the 30 gallon topoff tank.
The middle tank is the only tank that feeds the system, The salt is for emergency and regular water changes, the fresh is to renew the topoff tank. Since the topoff tank has chemicals added to it I need a pure supply of r/o water. Thus the left tank. I got them at tank Depot in Fla.