Marwen, How much does it weigh?
Wings with less than 4 inches of chord have ridiculously bad Reynolds numbers, so take that into account [if this applies to your tandem winged canard]. The canard won't contribute much to lift like a larger scale canard with good reynolds numbers will. This is why I think that a truly great flying 1/2A sized canard is very hard to pull off while still looking like a sporty sport model and not some dorky looking, glideresque monstrosity
My experience with a 1/2A sized canard showed me that the forward pitch controller has a hard time deciding whether or not it is an elevator or just a speed brake. I tried alot of different things with this plane before I decided to scrape off the canard and turn it into a flying wing......then it flew great.