Adopted Japanese Acer

Hi! Can anyone help?

I've recently adopted a Japanese Mapel Tree and it's started to look a bit down in the dumps over the last couple of weeks.
By that I mean the leaves are drooping as if I haven't watered it and one or two leaves have dropped. (I think it's either a 'Inabashidare' or 'Crimson Queen'). It's around 5' high, the canopy around 4' in diameter and it sits in a pot around 50cm in diameter, 40cm in depth. It sits infront of my house which is in full sun from dawn til' around 4pm.
I water it every other day and feed it every 2 weeks with ericaceous feed. Am I watering it too much? Is it the aspect?

 

hello it may be the aspect acers do like dappled shade hold back on the water except in really hot weather but do not let it dry right out :D :D

 

What are you watering it with? Acers like soft water - rain water if poss. The chemicals in tap water are not to its liking. I killed mine that way!