1000 ppm of hydrogen peroxide will disappear your plants like a dead body in baltimore. Seriuosly it may vaporize them. 100ppm max will destroy algae. get 35% horticultural grade (actually for hydro)
what kind of ml/gal do you use? All I know is that 100ppm is all you need to kill everything you need to. so i think ur at least wasting the stuff.BTW, just to slam the point home, here's a DWC using only hydrogen peroxide at 1000 ppm. Amazing....no vaporized roots, in fact they thrive.