Looking for advice/opinions

[Trigger Man]

It no longer goes with wattage per gallon in deciding the light. You need to look at Par values. On your 90 g you can go with a 4 or 6 bulb unit and you will be able to grow any sps you want in almost any part of your tank. Digital Audiophile has given you a good bulb combo. My Tek combo is KZ new generation, KZ fiji Purple, Ati blue +, and now GE 6500 (was a Ati superbrite but just seeing if I find any difference between it and the GE). I used this combo for a while now, replacing the needed bulbs with the exact same new ones when needed. Recently I did add a hagen 2 bulb because my lights are currently closer to the front of the tank then the back, so the hagen is in the back and it has a KZ 10K, and the Glo 17.5K bulb.
I have a 5 foot long, 24 inch deep tank and am able to grow all SPS as well as having LPS along the sides. I place my birdsnest and Monties at or near the bottom, but I also have a Green stag a few inches from the bottom and everything is growing.