Well, you may have light bulbs that are inappropriate for saltwater. Saltwater bulbs are a higher Kelvin rating. Kelvin is the color "temperature" of the bulb. The higher the Kelvin, the more "white" the light is, lower Kelvin is yellowish. A popular Kelvin rating in saltwater is 10,000K. Coralife makes a 10,000K bulb that does a good job. Since you have space for 2 bulbs, you may want to use one Actinic bulb, and one 10,000K. The reason I asked about your bulbs is that if you have the wrong Kelvin you will encourage the growth of nuisance algae over desirable algae (coralline). If you get the correct Kelvin rating it will definitely help get rid of your red algae(cyanobacteria) and make the corraline algae grow better. BTW, fluorescent bulbs put out desirable light for up to a year, then they start to shift their spectrum to an undesirable one. They still light just fine, it's just not the light you want. Compact fluorescent do reach up to 18 months before they shift spectrum significantly. Good luck, HTH.
