Hey,
Tank size is 210 Gallons. My water changes are automatic, about 40 gallons of treated RO water is pumped into the tank every 30 hours or so. One of the benifits of having a reef ready aquarium are the overflows. I use one for filling and the other is for draining. When the water level rises in the tank the excess water just goes down the other overflow into a garden hose I have hooked up to the bulkhead fitting underneath the tank which I have plummed to my backyard lawn. It's sooo nice!