T5 is the latest and greatest lighting method. But, that doesn't mean that T12 bulbs no longer provide adequate light. The advantage T5 bulbs have is that their small diameter allows you to use a reflector for each bulb, and capture most of the light the bulb emits. That makes the T5 fixture more efficient than a T12, T8, or CF (bent T5) fixture. For an 80 gallon tank, I would try for about 150-200 watts of T8, T12 or CF bulbs. But for T5 bulbs I would limit the light to about 150 watts maximum. If you have 6-55 watt CF bulbs, you have 330 watts, but a less efficient fixture than a comparable T5 fixture would be. I assume the fixtures you have do have good reflectors. If you removed half of the bulbs from those fixtures, you would have 165 watts, which should be about right. A new T5 fixture would give you more light, but you don't really need more light, and you could get it if you wanted it by plugging in another 55 watt bulb.