Mixed Lighting

Absolutely, if you have a canopy. They just make better sense. That's what they are designed for. I like them and they give you more room for reaching into your tank.

 

So, for growing SPS in a 90, could I get away with a 6 bulb fixture or would I need the 8 bulb. I was planning on keeping them all in the upper half of the reef.

 

Try the 6 bulb if it's financially better and you can always add a 2 bulb or a Metal Halide if you need it later.

 

The 6 bulb will work great in your tank (8 bulb may get you quicker growth). Like I mentioned before I've got the 4 bulb 4 footer in my 5 foot tank and it has grown everything with no problems. I recently added a 2 bulb 3 foot unit but that was because my lights were positioned more to the front then the back of the tank so I had room in the back to add some additional lighting.

 

There is an old adage that says you should try and have 4 watts to the gallon. Was that before T5's? I only know that I have 4 39W T5's in my 65 gal and it is fine. Like I said you can always add more later if you need to.

 

I guess that was before t5s. I'm looking for a 6 bulb fixture for my tank. We'll see what happens.