the 2x30" is a good idea....but 260 watts on a 100 gallon would be pushing medium to medium-high light and may require CO2
. A couple options....either replace one bulb in each fixture with an actinic (if you buy SW
fixtures this is likely how they will come anyway), which reduces the "plant available" light to 130 watts, or buy two 30", 65 watt (1 bulb) fixtures. The disadvantage of the second option is that the 65 watt bulbs are 24" long which might leave some darker spots, and the two bulb fixtures will be more flexible down the road if you decide to try some higher light plants.