Ecotouch tankless water heater 240v

I have a house with four females that were complaining that there is not enough hot water to take a tub. So I installed to tankless water heater so help out my regular water heater. I picked this tank because I had no option to add a circuit breaker to my panel so I split my dryer wire with two 30amp breakers. We only turn the heater when going to take tubs and don’t use the dryer.