Correct, PC Lighting is minimum as far as type, but your wattage is a tad low.. Looking at your tank you need to assess depth as well as wattage, in my tank I have a bta under 72 watts of PC's and its only a 29 gal cube.. but its 20" high which is what a 55 gal is. I think you can do it with a BTA, but its close. If you look at it as depth of your tank you have enough watts to sustain photosynthsis but your volume of water assesed as watts per gal is below what is recomended.. Thats not always a determining factor though. My BTA is perfectly happy in 72 watts of PC lighting. Although 260 watts of PC's lighting is great IMO I dont think its necessary for a BTA.