I am building a 120 gallon reef tank. I'm torn between building my own sump or i have the chance to buy a used trigger systems 36" Ruby sump used for 200.00. Or was thinking of building a 55 gallon sump. Not sure what exactly building one entails or the costs. You experienced reefers out there. Would it just be wiser to buy the trigger systems or would i save alot of money by building my own?