Thanks for your replies.
I will try longer exposure times. 3min is my usual exposure time, limited by the light pollution here. But Ha is a different game of course. May have to fix the DEC backlash before trying longer exposures.
It was my first attempt with the Ha filter. I had it for a while but could not find a way to mount it until the brilliant moment to just sticky tape it
Nothing is perfect about the setup, 1/4 efficiency of the DSLR and <1/2 efficiency of the filter. However, it is a cheap starting point and the best thing is that the moon is not the limitation any more. Now if only clouds would go away...