I live in a 3rd floor apartment, wood floors, air conditioning that doesn't work, etc. I keep a 55 gallon tropical fish tank and a 20 gallon taricha granulosa tank. I use buckets and empty them into the toilet and fill them in the bathtub. I have five 5 gallon buckets to do weekly changes in the tanks. And do it very assembly line like. I siphon the water into the buckets first, carry one bucket into the bathroom empty it and put it into the tub and start filling it, then get the next bucket, empty it, take the full bucket out of the bathtub, put the empty bucket in to fill and carry the fresh bucket out and fill the tank, and so on... It's very efficient and very quick. When I redo substrate, which I tend to do about once a year, I put the inhabitants in a rubbermaid bin and then siphon as much water as I can out of the tank and just use a large glass and scoop out the substrate putting it into buckets. I then pour as much water as I can off of it and leave the buckets to dry out. I usually then put the dry substrate away somewhere for future re-use.
Take care,
Mary.