conda & OldmillXxX: As stated earlier, part of the reason my sand remains clean is due to the high current levels in the tank. The Penductors and the sinusoidal valve keep currents very random which constantly and gently moves the Southdown sand about. Very little gets waterborne but there is always dunes or wave shaped formations that alter due to which Penductor is on (6-hour rotation for tide simulation). The natural movement over time has been for the majority of the sand to accumulate towards the back as it travels through the valley. Personally, I prefer the look of this as it does give a natural look, in my opinion. Perfectly flat sand beds don't appeal to me.
The downside to all this is that it is a delicate balancing act as to where the outputs are aimed. For instance, after having taken that previously posted shot where I moved the left and right sinusoidal valve outlets, even after placing them back to what I felt was as close as possible to their original positions, the slight alteration has created new sand movement patterns. Not always a bad thing, just sometimes different. Other times, slight tweaks are required to prevent large amounts of movement. Again, it's all part of the balancing act which is part of the overall challenge.
Ixthys: I do really like the Ozotech ozone generator in that it is ultra powerful, of great quality and trouble free. It has a dial for the level of output which I run at the minimal setting of 1 on a scale of 1 to 10. I don't run a dryer but do run its input air through the large floss/carbon filter which I'm sure helps some. But again, this unit is so powerful that drying the air for efficiency is not required, in my case. As far as control, I used to use the ORP control on my AquaController II but it was so stable that I now just run it 24/7 at the aforementioned lowest setting. This seems to prevent the swings produced by a constant on and off at higher output based on the ORP readings. I do still have programmed in a shut-off for when the skimmer is shut down (too high a pH... which raises the sump level to prevent more Kalkwasser additions) and a too high ORP level, just for safety reasons. This never comes into play, though, thank goodness.
While Ozotech ozone generators are more expensive than others initially, I feel the longevity makes it cheaper in the long-run. Mine has been running without flaw for over 8 years and I bought it used, albeit briefly. I know this sounds like a commercial but is in fact my true belief.

No kickbacks have been provided.
Joseph