dhnguyen,
I used to own the 6045 and tested them with a kill-a-watt and were measuring 1 watt less than the 6025s (although the original Tunze spec on the 6045 was calling for 8W I only got 6W). I believe that the 6025 has a stronger transformer and therefore pulls 1 extra watt and spins the magnet faster. With the mods that we've done on the 6025 it is obvious that exceeds the 6045 performance. My next post will show the modded 6025 measurements. Keep thinking on the prop idea though... I'm so interested and yes, I 'll do the flow measurements.