What is the difference between the Pentair Mastertemp and Mastertemp 125 heaters?

The key difference between the Pentair MasterTemp and Pentair MasterTemp 125 heaters is their heating capacity and intended usage. The MasterTemp offers a range of models with higher BTU ratings (up to 400,000 BTUs), making it suitable for larger pools and commercial use, while the MasterTemp 125 has a lower BTU rating (125,000 BTUs) and is designed for smaller pools, spas, and above-ground pools. The 125 model is also more compact and energy-efficient for lighter applications.