Should I decrease the dosage or stop dosing?

I’ve been dosing about 1/4 of a cap line of Seachem Flourish to my 20 gallon for a couple days now. Some hair algae has been popping up so I’m thinking if I should stop dosing it all together or decrease the dosage. I keep my lights on for about 8 hours a day usually but since the algae showed up I’ve been decreasing to about 6 hours.