Algae is pretty hardy - it will grow even in less than ideal light. As the light level lowers, you will begin to get black or brown colored algae - not the bright green stuff. At least the bright green is rather pretty and is very nutricious for the goldies.
After approximately one year, your flourecent bulbs will be giving off far less light than they were originally designed to produce. So, chances are, unless they are new, you already have less light that originally.
There are not too many pleasant wavelengths of light that you can use - what you and the fish enjoy, the algae does also.
Keeping your nitrates as low as possible, limiting the number of lighted hours for the tank, introducing real plants to use the nitrates in the tank, adding snails or a quality algae eater are all options to consider.
Algae is a fact in fish keeping. Rather than rail against it, I have learned to accept it, deal with it and go with the flow.