which one is better?

http://www.amazon.com/45851-Compact-Fluorescent-Aquarium-Terrarium/dp/B0002U56O8
i have 2 of these over a 55g with shiny metal reflectors. they are 55w and 9325k. would it be better if i bought a 55w 6500k bulbs or stick with i have or buy maybe 36 or 40 watt 6500k? im trying to stay low tech. im having an alge problem and my bulbs are only on for 5 hours a day. i dose 2 times a week flourish,iron, kh2po4,and kno3. any recomendations id like to stay with the fixtures i have but am willing to buy new bulbs. thanks