You're using both acid buffer and alkaline buffer? What type of acid buffer are you using? I would recommend if you wanted to drop the pH then only use the acid buffer since the alkaline buffer will raise it. Also becareful as to what brand of buffer you use, because many acid buffers contain phosphate.
The lighting method you discuss is the dupla method I believe. Dupla claimed that the aquarist should run the lights with intervals of darkness to help compete against algae. I believe it went (3) 4-hour diurnal periods interspersed with (2) 1-hour nocturnal periods, but I might be wrong. I had a friend whom used that method with great success albeit it was awhile ago. If you are interested in it I could ask him.
As others have suggested algae is easily attributable to an imbalance in nutrients. I do not know how experienced of an aquarist you are but I personally find 130 watts of light to not be enough for my 29g grow out tank IMO. However, I can see how such a setup could easily get out of hand.
If the algae is serious, bleach is not a method that should be used. Instead try diluted hydrogen peroxide (5 H20: 1 H202). If you have a pipette to directly treat the algae as opposed to pouring it directly in the tank then that would be best. After 4 days of treatment do a good 25% water change.
Another recommendation, which I attribute to helping me keep algae under control, is in smaller tanks utilize Seachem's Flourish EXCEL. It could replace the DIY co2 that you are currently using for a carbon source and does well to combat algae IMHO. 1 bottle should last you 2-4 months.