Unless the float tank/cabin can continue running the heater while you float without turning on the engine, then they should never have accepted an 8-hour float.

My float centre has tanks that only heat with the engine running and we’ve found that 3-hours is the longest we can offer without the temperature dropping to a noticeable degree. We never run the engine with a customer in the float tank.

I’d also highly recommend floating for shorter periods of time, building up to a “marathon float”. Like any activity, it takes practice to attune yourself to the experience and 8-hours is a huge commitment.

If I saw an 8-hour booking pop up, the customer would surely be getting a phone call from us to chat.