As my Rio180 is in my bedroom,
I use a Fluval3 head with a dedicated hosepipe bought specially for the job to empty the water from tank to bath,
I set the head to the water height I want to remove so it's not possible to take too much out.
When it's time to refill, I attatch the pipe end that was emptying into the bath, to the electric shower outlet pipe,
set it to 30C and low flow, then off we go
Dechlorinator in the tank 1st of course. Easy peasy, no fuss, no mess.
Before emptying, I hoover the substrate thoroughly, taking my time ( it's quite relaxing
)
agitating the sand a little with a spare fish net to help kick up any buried poop. Works really well.