Heating 5000 gallon above ground pool for an outdoor event

[Denebte]

Hello, I have an outdoor event next month and we will have mermaids there. We have a 5000 gallon above ground pool we'll be setting up. I've looked into tankless water heater and it was the route I was thinking of going until I realized they are only designed for shorter is use and would probably fail if used for 24-48 hours straight. I've thought about using a copper coil and a propane heater with a water pump. Would this be a viable option? I would like to spend under $300 if possible. If anyone is in or around Pocatello Idaho next month this will be setup at Mystic Realms Fantasy Fair.

 

[bkp22]

Build a campfire and use a copper loop over the fire as a heat exchanger. They make them for DIY hot tubs (expensive) or you can do your own by filling it with sand, crimping it, bending it. Will fit right in with your fantasy
vibe.

 

[Denebte]

Build a campfire and use a copper loop over the fire as a heat exchanger. They make them for DIY hot tubs (expensive) or you can do your own by filling it with sand, crimping it, bending it. Will fit right in with your fantasy
vibe.

Unfortunately we can't have open fires on the grass. Thus the propane heater.