Closing pool up for the year, and looking for ways to keep the rodents out of the pool heater. This is our 2nd Raypak heater. I discovered that the floor of the heater has rusted out, and other areas are rusted out as well. The vertical panels near the bottom fell right out, rusted and dissolving. Natural gas is not available in my area. Only turn the heater on when we have guests. Use the heater probably 5-6 times a year. Trying to determine if I should replace again or just live without. Have there been any improvements or new technologies in the past 10 years that would be worth considering?