I forgot to add to my original post. My house was ru ning 90-100 before tank. With tank 125-135. Then summer hit. With chiller and random AC I've been 200, 220, and 250 this month. I rarely run the AC. Only when its over 90, humid, and I'm home aLl day.
So maybe you're 300-400 becuse its summer and AC? I put 4 pc fNs on my tank and I swear my chiller never turns on anymore. It use to turn on on days that it's only 85 outside. With fans 90 degree outside no problem. Chiller stays off. But remember summer bill goes up. I was well into 4th tier. So I was paying g about 25 cents a killowatt or whatever. Or for better comparison on the bill. Before tank I was using 450kwh a month. Last 3 months 800 kwh+