never ran a herbie but took some physics years ago and it would tell me that a herbie (creating a full syphon with ZERO air) will drain much better than a durso style drain (air takes up space) a 1" durso gives you 600 gph a herbie style drain 1" would not surprise me if it was capable of 900-1000 gph(this was just a guess) i wish i went herbie style so its silent
