my lights and plants

Actually the CO2 will not hurt and will always help. You should not need ferts. You could try a 65 watt pc fixture, that will give you decent light but not an uncontrollable amount.

I totaly agree with you on the CO2 issue. If you look in this forum you will find an amazing post by Tom Barr encouraging the use of CO2 on low light tanks. The picture of a low light tank in this post is just amazing.

I diffused CO2 in a low light 15 gallon and the difference was very noticeable!
 
Also to be clear the watts per gallon refers to compact florescent bulbs not regular incandecent bulbs.

Watts per gallon refers to T-12 fluorescent tubes. T-5, and compact fluorescents, both put out more light per watt than T-12's.
 
Its better than if they were T-12's, but it is still very low light.
 
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