salt water hot-dip tank

Insulation ?

1. what is the rate of heat loss useing what insulation you have on the tank. 2. How many pounds of fish per load is placed in the tank? 3. calculate the heat needed to raise that fish to 150* F (or what ever temp) 4. Add the two losses together and that will tell you the boiler needed. It is just that simple, remember that 1 btu will raise 1 pound of water 1*F. Time comes into play when you want it done in a particular time frame.
Good luck

Heat it with a heat exchanger,that is the boiler medium is kept sepereate of the tank water

Bigugh