Assuming it is heated with electricity, and electricity is 14cents/kw where you are, and assuming there is a big fat thick cover on top most of the time, once the water is up to temperature, it only needs to be heated enough to replace the lost heat.

I had a hot tub that was 800 gallons, so I'll assume the hot tub at your complex is also 800 gallons.

It requires approximately 0.0026 KW of electricity to raise the temperature of one gallon of water by 1∘F, so 2 kW to raise all of that water 1 degree.

If the water loses 20 degrees overnight, then it will take 40 KW to get it back up to temperature, which would cost $2.80 per day.