Obviously the tanks are optimized for whatever it is they do (emulating senselessness?) but is it possible to emulate that?
How much epsom salt would you need and would it be cost-effective and safe to go down the drain relative to going out to an actual tank?
Please tell me it isn’t completely impractical and it could be done :)
I think your best bet is probably some kind of kiddy pool/pet bath with sufficient depth. Even most jacuzzi style tubs aren’t actually big enough for an adult to float in.
Would take a lot of salt though.