Sorry xenaph nobody has helped but I'm learning myself and am also having algea issues. Had a huge BBA outbreak while I was out of town. I started dosing excel and it turned brown and went away. Now I have some green low lying algea too. I think my zero nitrates is my issue. Learning that 10-20ppm of nitrates is optimal unless there are fish then shoot for 5-10ppm, co2 20-30ppm. If your parameters are there then I'm not sure. If it's a small outbreak just spot treat with excel or hydrogen peroxide before it becomes a nuisance like mine. Ultimately though it will return unless you can pinpoint the cause. How heavily planted is your tank?
Look in this Algae Forum for the One - Two punch to remove it, does a great job for me. You may need to remove some stem plants and dip the ends in H2O2/excel to remove those and scrub off as much as you can.
Next you need to get to the root cause and it can be difficult to find the right equilibrium for your tank to keep alage from growing, new tanks are especially hard.
First off is some info, what kind/size of tank? Is it new? What lights? How long are the lights on? this kind of stuff can help some of the gurus with lots of experience pin point an issue (im still novice). How much plants? Do you have a whole tank shot? Maybe that you are putting too much fertz and not enough plants. Do you start your CO2 well before you turn on the lights? Whats water parameters?
These are the things I try to do after a One - two punch:
*Note Id recommend trying these individually if you can, or just 2 at a time. It does take some time to narrow it down.
1. Crank my CO2 (like 2x or 3x) and watch my fish to make sure they arent gasping through out the day. I found that i can really crank it more then my pH kit tells me I can and greatly reduces the algae.
2. Drop the photoperiod of my lights, giving a total of 6-8hrs (7 is usually where I start first) and see how that goes after a few days, increase if you can.
3. raise my lights 3-5" and/or cover the tank with a screen/floating plants.
3. Reduce fertilizer frequency.
See if those get you anywhere, if none of those help you may need to try RO/DI water. There are much more knowledgable people around here that may have other suggestions, but these are some good basics to get you started.