My various trips abroad have given me the opportunity to visit many fish rooms and see the various set ups. Most have about 20 tanks of small to medium sizes and to be quite frank, it is clear that size does not matter. Many of the best aquarists and breeders have smaller set ups because most often there is simply not the space to have a large collection of tanks. The vast majority of fish rooms are maintained in a traditional way with syphon tubes and a bucket.
I have a new fish room with something like 240 tanks. It would be impossible to keep these with just a syphon hose and bucket. I have therefore installed a semi automatic water changing system.
The water is fed through a boiler and a thermostatic valve to ensure the correct temperature. (I used to use cold water with my wild livebearers but guppies are much more delicate - and much harder to keep). I manually open a valve to allow the flow of water.