My biggest current sump is a pair of roughly 75-gallon bins hooked together in series; typical water volume actually within is about 120 gallons. Not only does this give you a massive increase in total water volume in your system, but you can easily access the inside of the sump to make changes in configuration, add auxiliary equipment like heaters, UV's, etc. I wish mine were just a single large container, but the design of my stand makes that difficult...and I already had these two big bins, so...
Your nice big second tank would allow you to devote perhaps one end of it to equipment, biomedia, etc. and still leave you with plenty of room for use as a refugium or anything else you wish. It also gives you room in which to keep one or two large sponge filters running, powered by air or powerheads. These come in extremely handy when you have to set up a tank on short notice, for unexpected acquisitions, fry grow-out, quarantine, etc. A pre-cycled sponge bypasses the cycling of such a new tank, making it immediately usable.
Finally, if you are the sort of aquarist who enjoys looking at and bragging about the perfect pipework and meticulous wiring of the equipment that keeps his tank running, oohing and aahing over flashing lights and digital readouts...well, a great big sump seems to bring a lot of "street cred" along for the ride...
Your nice big second tank would allow you to devote perhaps one end of it to equipment, biomedia, etc. and still leave you with plenty of room for use as a refugium or anything else you wish. It also gives you room in which to keep one or two large sponge filters running, powered by air or powerheads. These come in extremely handy when you have to set up a tank on short notice, for unexpected acquisitions, fry grow-out, quarantine, etc. A pre-cycled sponge bypasses the cycling of such a new tank, making it immediately usable.
Finally, if you are the sort of aquarist who enjoys looking at and bragging about the perfect pipework and meticulous wiring of the equipment that keeps his tank running, oohing and aahing over flashing lights and digital readouts...well, a great big sump seems to bring a lot of "street cred" along for the ride...
