Back to the fuel gauge

I had a similar problem with my new tank ... I put 5 gallons of gas in the 18 gallon tank and the gauge read around 1/8 or less ... Well today like a dork I ran the car out of gas .. banged on the bottom of the tank and could hear the float bouncing off the bottom... Once I got home I pulled the sending unit out and bent the float so that it was just above the suction sock ...poured about 12 or 13 gallons and now it reads 3/4, so just about right ..