I created the black beauty tank and floated in it while living in Margate, FL. Full instructions are here.

It was built in 2011 (?) and is the predecessor to the Ragtop DIY Float Tank, built in 2024.

the lip of the tank is a bit narrow for the Tarp Mahal metal poles, but it is much easier to climb over the ledge… because it is not as high a tank. PDF included here for posterity.

and lo and behold, PBM tank supply still carries this tank – The Norwesco 360.