You do know that the take off is different than land planes!!!!!!
Hold full up elevator to cause the plane to rock back on the rear of the float/s and as more throttle and speed is gained ease off of the full up elevator to neutral and the will climb up on the step and really accelerate, a little up the time and it will lift off.
Technique will go a long way in getting into the air especially if you are useing a low powered a/c.
Or you can just horse it off with high horsepower and risk a snap roll on take off. A lot of guys do this and get away with doing this, but when it snaps they understand what happened. Saying Iv'e done this for years doesn't make it right!!!!!
Tom