I was palnning on running it 24/7 until the green water cleared up, then add it to my light timer.
That is quite fine. However, any sign of disease in the tank, crank it on 24/7--UNLESS you are going to med the whole tank and the meds you will be using are sensitive to UV--consulting the manufacturer should point you in the right direction. The guy at the LFS will, most likely, just tell you his/her best guess.
Be prepared to be amazed at the benefits UV can add to a tank ...
Regards,
TA