On aircraft with this configuration, putting the flaps down causes a nose-up pitch.
You need to mix in some down elevator trim to control the nose up pitch, BUT

another tip

don't trim it ALL out! Leave in a litlle nose up pitch such that the model sits on the landing approach<u> In Trim </u>at a nice slow but safe approach speed. It is nice if just putting down land flap changes the trim from cruising around trim to slow approach trim without touching the lever. You find that by experiment and practice.

If, as A7Bldr implied, you mix in down trim so that there is absolutely NO nose up pitch then the model is trimmed to an approach speed that is too fast, and that leads to a very floaty landing. Some people correct this by applying up trim on the trim lever (the correct method), others slow down the approach speed by holding a little up (back) pressure on the stick (a definite No-No in full size flying) but getting the mix just right for the speed change is the best solution.

never tried Crow! I'll try it one day, but it goes against my full size flying background so I'm prejudiced against it. Many modellers think it's great however.