Let's say you have a planted tank with slightly excessive lighting but still no algae. The aquarist adds some fertilizers, and then algae shows up, so the aquarist blames the fertilizer, when the actual reason is there was a bit too much light to begin with, and adding the nutrients enabled the algae spores to take advantage of the available excess light energy. This is because the lack of nutrients is no longer limiting growth, and the insufficient amount of co2 now becomes the limiting factor for plant growth. The plants struggle with insufficient co2, algae not so much, so guess which one wins. Keep adding the ferts, but either reduce lighting, add co2, or add more plant mass, (or all three) and you would very likely see the algae subside and not return.