Flotation therapy has been gaining in popularity due to shows such as Stranger Things and The Joe Rogan podcast. Now it was my turn.
The lid closed, cutting off sound and vision from the outside world. My breathing slowed, the bird sounds stopped, and I was alone.
I was at FloatFix, Dunedin's first float centre. It is part of a growing industry which now has 17 float centres around New Zealand.
I had arrived earlier that afternoon and met staff member Kim Bates, who had me sign a form and talked me through what would happen.
I had to shower first, to remove any skin oils.
Then there were ear plugs to wear, to reduce sound and stop the epsom salt water going in.
I'm a tall guy and I was surprised the tank was big enough, but it was roomy.
I was able to stretch out completely.
It was like a giant shell or pod that closed over me and blocked out the light.
Inside were two buttons. One controlled coloured lights, for people who are afraid of the dark. I left them off.
The other started the float session with 10 minutes of bird sounds.
This was followed by 40 minutes of silence and then another 10 minutes of birdsong to bring you out of the session.
The water feels like normal water, but you can't sink in it, even if you try.
I did try, by blowing all the air out of my lungs. But I was held aloft in 25cm of epsom salt-saturated liquid. It was a strange feeling.
It took me a while to relax. I kept thinking about what I would write about it when I was done.
Eventually, about 20 minutes in, my mind and body relaxed fully, and it felt like those drowsy moments before sleep.
Some people say they see stars and visions in the darkness.
I didn't see any of that. But the experience was like nothing I had ever felt before.
The water was about body temperature, and I forgot it was there, feeling as if I was suspended somewhere out in space.
Float therapy has existed since the mid-20th century, when American neuropsychiatrist John C. Lily developed the first float tank in 1954, to study the effects of sensory deprivation.
It was designed to reduce sight, sound, taste, touch and smell.
It has become more common in the West over the past few years, popularised by people such as the character Eleven in Stranger Things and UFC commentator and podcaster Joe Rogan.
Floatfix co-founder Karl Bloxham discovered floating via Rogan and decided he wanted to have a go.
He said a lot of customers had similar reasons for starting.
''Most people are just intrigued, and think 'that sounds cool'.''
But others had more pressing reasons, such as relief from chronic pain, depression and anxiety.
''Everyone gets something different, which is the beauty of it,'' he said.
Mr Bloxham took his first plunge while in Australia and wanted to bring the experience home.
He worked with Otago Rugby as a strength and conditioning trainer, and incorporated floating into the rehabilitation process.
''We get each of the players to have at least one float.''
Since starting the company 18 months ago with physiotherapist Ash Stiven, Mr Bloxham floated himself at least once a week, and he said it had helped with his own injuries.
''Especially around my back and hamstring, where I've had some major surgery.''
After my float I felt extremely relaxed, almost drunk.
However, it was not until the hours after that I realised the full impact.
The loose feelings continued, but were joined by waves of smiles and laughter that I could not control. Everything looked new.
