The capacity of bath tub in beauty salon is about 200 liters. The water temperature in the bathtub should be 50 degrees. Ten-liter gas water heater, the water output in winter is about 8 liters/minute, and it takes 50 minutes to fill two barrels of water! In winter, the water output of the instant electric water heater is at most 4 liters/minute, and it takes 100 minute to fill two barrels of water! Before the water was filled, the guests had already run away! It is recommended to use a large-capacity electric water heater of more than 400 liters. Baidu should be able to find a manufacturer.