Hi Slydog -
According to my calculations, your compressor won't be able to push air much deeper than around 15' (requiring 8.7PSI) I also recomend membrane diffusers as they will put less back pressure on your compressor. Weighted hose definately 'out weighs' the un-weighted as far as ease of installation and less hassle with sections of unweighted hose floating to the surface.
