Rob, point taken but a tank can easily be made up.
4 4inch plastic piping laid out in a square or rectangle as needed.
Lay polythene over them and you have an instant tank to clean rugs in.
You can leave out one of the ends so you have a tank with a continual flow if that makes sense.
Drying is a different matter but if you get a heavy roller, something like a 250lb vinyl roller you can squeeze out most of the moisture before you start drying.
But again, point taken, best, Dave.