I just did a partial fill on that 55 gallon tank that i got recently, and i don't know how you guys with really large tanks do it. I only filled it up about 5 inches of water to test for leaks, and that took for ever, as well as trying to empty it, it also took forever, i could not imagine when i get the 125 gallon tank i want, what its gonna be like. Then to think about frequent water changes OMG. im gonna have to definatly make sure that i use the filter media from my other tanks to cycle this one, i cant imagine going thru several water changes a week on this tank or the 125. OH and thank god i have a python. I would cry and probably give up the hobby if i had to do buckets on a 125 shoot for that matter even on this 55 lol