scrapper

Milwaukee salinity tester 70$ Flipper float 25$ Flipper nano 10$ Nero 5 200$ Flipper max 50$ X2 finnex heater controllers 25$ each All plus shipping

Hello was wondering what people use in the biocubes to clean the front corners? I tried to use a flipper and i scratched my tank a little bit. I went really slow and i just cant find a way to clean up the hard algae thats growing on the corners of my biocubes glass.