Yes, the tank is for both the drip system and doing very large (up to 250 gallon) water changes. It is raised up so I can just use gravity to feed water into the sump. The fresh water will be entering the top of the 275 gallon container and when full will overflow into the tank. The drain will be away from the fresh water inlets to minimize the amount of fresh water leaving the system. I haven't set up the drain yet. Thanks for the compliments on the plumbing!