When Spot treating with H202 you need to shut your lights off . Or it will break down the the H202 I had a bad case of BBA and use a 32oz in 3 days and it clean every thing in mt tank wood,equipment, plants and gravel, By raising my CO2 and adding a HK pump I was able to keep it at bay. Here are a few places to check out.
http://www.gpodio.com/h2o2.asp http://www.theplantedtank.co.uk/algae.htm http://aquariumalgae.blogspot.com/ http://www.aquariaplants.com/alqaeproblems.htm