If its just a water change then I also do a 50% weekly water change on a 250L tank (apox 200L of water after hardscape deduction) in about 20-30 minutes. I can clean the glass and one of my two filters in this time aswell without breaking into a sweat.
All I use is one hose which is long enough to reach from my planted tank in my living room, to both my downstairs kithen sink and the barrels in my fish room upstairs (not at the same time though). On one end is an adaptor which is identical to the spraybar adaptor from my main external filter (EX1200). So all I do is turn the filter off (using the filters output control valve) unplug the spraybar within the tank, plug my hose in instead, secure the other end into the kitchen sink (via a homemade bracket) and turn the filter back on. That gives me about 10 minutes to clean the glass make a coffee whatever. When sufficient water has pumped out I turn the filter off (using the filters output control valve) but leave the hose connected to the spraybar adaptor, take the hose, which remains full of water, upstairs and put it in a barrel of prepared water which has other barrels connected via syphons to it whereby they effectivly become a battery of barrels(again secured in place with homemade brackets). I then go back downstairs and unplug the hose from the spraybar connector and the syphon starts automatically as the hose is already full of water. This is then secured in place again with a homemade bracket and I finish my coffee or whatever else I was doing. All that is left is to empty the hose, coil it up and store it away when the tank is full. Job done in 20-30 minutes, aproximatly 100 litres in and out and not a drop spilt (hopefully, LOL).
Of those 20-30 minutes only about 2 of them are required for actually dealing with the water which does leave a fair ammount of time available for doing other things like a bit of light prunning or general tank cleaning and i have even managed to clean out both of my filters in the past in this time, one whilst it was draining and the other whilst refilling although I did break out into a sweat on that occation, LOL.
About once a month though I spend a lot more time on tank maintenance. Typically this would include planting/pruning, cleaning lights, filter pipes, gravel , cabinet, etc, and anything else that needs doing. This can take quite a long time depending on how much there is to do. Sometimes just an hour or two but if I take on a rescape or have hardware to add/remove the job can take an undetermined length of time and has taken upto a whole day in the past on more than one occation.
Regards, Chris.