Why does my amp keep blowing fuses?

I have a planeet audio anarchy 1000 watt amp. ik its not amazing im upset i bought it. but its running 2 kenwoods ( typhoons i believe. they have a kinda swirly design and an M in the center) and i have them running at 4 ohms n my amp supposably kicks out 700 watts at 4 ohms. so why does the 20 amp fuse keep popping? i have changed it prolly 4 times in the last 2 days