We report here on results from our completed ultra-deep blind HI survey of two galaxy clusters at a redshift z=0.2, performed with the Westerbork Synthesis Radio Telescope. The field of the X-ray bright, massive Butcher-Oemler cluster Abell 963 was observed with a total of 117x12hrs integration time. Additionally, Abell 2192 was observed as an example of a more diffuse cluster with a total of 73x12hrs integration time. In both fields, sampling a total volume of 7x10$^4$ Mpc$^3$, the expected noise levels were achieved. These HI measurements are part of a multi-wavelenght survey including Spitzer, GALEX, optical data and restframe 1.4 GHz radio-continuum. We will discuss the number and distribution of HI detections and the HI content of the blue galaxies that are responsible for the Butcher-Oemler effect in Abell 963.