I would do a water test and see what kind of nitrates your measuring at. I would bet there pretty high. I agree with what's been stated about doing big water changes....this will help lower some of those levels. I'd look into dosing some liquid carbon if it's a small tank and you don't want to put a pressurized c02 system on it. Algae can't stand carbon.
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Algae is quite similar to plant life and also requires carbon to grow. Algae thrives in the same conditions as plants, even more so since it isn't nearly as fussy about nutrient concentrations. If you want to see an algae explosion just set up a tank without any plants but with lots of CO2, light, fertilizers, flow etc.
I don't agree with the advice to reduce nutrients without even knowing the concentrations first. Reducing nutrient levels isn't going to help anything if a nutrient deficiency is what caused the algae to take over in the first place due to poor plant growth. This is exactly the kind of algae that shows up in my tank when I
forget to dose fertilizers, not that it's necessarily the same scenario here, just giving an example.
I do agree that large water changes and reducing light intensity and/or duration will help. Keep light period at 5 hours per day for now, do some extra water changes, and pull out as much algae as you can. Excel will kill most algae so when you dose excel you can apply it directly to the algae using a syringe or pipette. For further advice, more info on your tank will be helpful. The size, lighting (did you mean current usa satellite plus?) and what is the distance the light fixture from the substrate? If possible, you might want to raise your light up higher to reduce intensity. Is there injected co2, or just excel for the carbon source? It might be necessary to increase available carbon either by injecting co2 or increasing excel dosage, which in turn will create higher nutrient demand so you will likely have to increase fertilizer dosage as well. What is your fertilizer regimen?