NEW HORSE SPOOKY

Question
I RECENTLY HAD MY HORSE DIE FROM CONTAMINATED FOOD. IN DEALING WITH MANUFACTURES OVER THIS ISSUE IT TOOK ME APPROX 2 MONTHS TO FIND A HORSE FOR ME AND MY DAUGHTER TO RIDE TOGETHER. I FOUND A 11 YR OLD TB GELDING. HE IS 17 HAND AND IS VERY GENTLE AND GOOD NATURE ON THE GROUND. I RODE HIME SEVERAL TIME BEFORE PURCHASING HIM AND HE RODE LIKE A DREAM. NOW THAT I HAVE BOUGHT HIM AND HAVE HIM HERE AT OUR HOME, HE SPOOKS AT ALMOST ANYTHING. HE RECOVERS QUICKLY, BUT WHEN A 17 HAND TB JUMPS 5 FEET TO THE LEFT ALL OF A SUDDEN IT IS CONCERNING. I HAVE YET TO PUT MY DAUGHTER ON HIM WITH ME. HE ALSO BUILDS UP AS YOU CANTER. THE EQUATATION CENTER I BOUGHT HIM FROM THINKS IT'S THE FEED. I HAVE REDUCED HIS FEED " SOUTHERN STATES PLEASE 11% PROTEIN". DO4ES ANY ONE HAVE ANY SUGGESTIONS WITH DECREASING HIS ANXIETY.

Answer
My first piece of advise is to put him on exactly what he was on before you bought him.  The exact feed and the exact supplements.  Changing a horse's feed right when you buy him and move him to a new location is never a good idea.  Put him back on the same regimen now, and later, once he is settled a few months from now, you can think about switching if you have to.
Secondly, when he does spook, you should ignore it, or make him go forward.  Making him go forward tells him that there is nothing to baulk at, and gives him an outlet for his anxiety.  Moving forward into work also tells him that when you are on him, it is time to work.  Keep him focused on his job by doing lateral work and different figures (i.e. serpentines or figure-eights).  Just because he is 17hh does not mean you should be frightened.  (A horse is a horse.  They are all big animals.) One thing you might try... When I am on a horse and he spooks at nothing, I actually give him a big kick and fuss at him a little and make him go forward, as if to say, "Don't be ridiculous!"  
Good Luck.
Be confident and sure of your self.  If he senses your insecurity, he will in turn be insecure and spook at nothing.  You need to show him that you trust him, and he will in turn trust you, therefore becoming confident in himself.  

Good Luck.