My 75g (album is in gallery) has 1 400w mh on the right, and 1 175w mh on the left. Four 32w actinics add good color but not much else. It's been that way for about 3 years now, and what follows is just some random things I've learned:
- The 175 Aqualine and Ushio 10k bulbs (doesn't matter which) have put out much more than the 1/2 you would expect next to the 400 (tried Ushio 10k, then ALS 12k). Visually, there's not even really that much difference after the first month (never tried anything more scientific).
- Traditional mh ballast gives up very *little* intensity to electonic ballast in the 175w range, and very *much* intensity in the 400w range. (I tried the Champion Blue Line - POS.)

(next post)....