I would do the 600 gallon basement pond build. Over a 135 gallon salt tank. I had a 125 salt set up for awhile and honestly is just to damn exspensive and time consuming to do. Besides the fact that all the salt water fish i like are big puffers, triggers, and lion fish, and none of them are reef safe. And to me having a cool reef is about the sickest thing out there. but what is the point if you cant keep any of the fish you like in the tank. And mixing up that much salt water all the time sucks. R/o systems are exspensive chillers are exspensive the lighting is exspensive and takes to much wattage to run all of the stuff you need for the system. So in short to me salt water is to exspensive and not worth the time or money. But a large fresh water ply build is. Just my two sence
