SunShine#4OtherSoiless Meds - Keep Moist at all times?

Growing Purps in SunShine#4, was reccomended this medium by a friend who I respect his work greatly. This is my second cycle through, and these aren't bulking up quite as much. Today he came over and the surface of the SunShine was dry, and he said you don't want that with SunShine... you want the top moist... he said basicly you could have the entire bucket pretty damn moist the entire run through and it won't fuck you with SunShine because it doesn't build up salt easily and the plants don't get over-nuted quite as easily with SunShine either. You guys agree with this? I was hand watering when I felt an inch or so down and it was dry, now because of this advice I am considering watering more often. What ya think

Nobody here uses SunShine at all eh? Kind of a simple question but maybe it's a rare medium to use I'm not sure.