Only after blowing off the powder.

I dunno about London but I’ve done salt float / sensory deprivation. My place has 2 square / cube tanks, and 1 orb / egg where the top can be open. Twinkly lights in ceiling, which feel hypnotic. My best advice is go as you are. Lean back and let the tank carry you.

I’m giggling at the Hotstepper song playing when you took the photo.