Look for "Japaneese tub" or upright tub on amazon... or whatever online shop you use.
Keep in mind, the tub will be very heavy after filling. And emptying it in a clean manner is virtually impossible. It has to be emptied with a bucket unti it is light enough to carry.
I tried to build a contraption to keep the goo warm... no luck so far. Best think for now was an isolating sheet beneath the tub.