Lighting change/algae

I have read a lot about this.. seen many posts. I didnt really change my lights so to speak. I removed the glass top cover off my tank which let a lot more light into my tank. I didnt change feeding or anything. Now I am seeing a slight algae growth. Nothing major just on the sides of my tank I use the magfloat daily on. Spots roughly 3-4 inches or so on the glass.
Should I worry about it getting out of hand? I dont really want to change my feeding, i only give a small frozen cube of marine cuisine daily. Params are still okay.

 

I upgraded my lights and expereinced similar, Im running sea chem Phos gaurd at present and the problem is going away

Steve