Hi, looks like Green Spot algae, and might be a consequence of your tank being newly set up. But if you have CO2 and Ferts at the right level(?)[this is important!]), then the only variable I would suggest changing is your photo period, which is a big factor with algae problems.
Keep the photoperiod at 7hrs max, but with algae problems, cut it down to 5hrs for the next couple of weeks, and of course regular water changes. Nerite snails are good algae eaters also, but dont rely of tank inhabitants for algae issues. The most important things to take care of with algae are the abiotic variables, such as photo period, correct nutrient mix and levels, correct CO2 levels, and sometimes light intensity, but if your photo period is low the light intensity shouldn't be a problem.
What works best for me is mimicking 'winter conditions', so shorter photoperiods (since doing this I have had no algae issues what so ever! Been my silver bullet for algae problems, although I keep a close eye on all other factors mentioned above).
Hope that helps, but as your tank is newly set up, a bit of green spot might be expected(!).. Check this thread out for a bit more info (although, there is plenty of info on the forum);
Aquarium Algae ID (updated May6th '10 Surface Skum)