With a CYA of 70, the shock level for FC is 20. you'll need to and keep it there or higher until the pool turns cloudy / blue. 4 gallons (not jugs, gallons) of 8.25% bleach will get you to 25. You'll need more to keep the FC at shock. Pour it in aroung the pool and mix it with a paddle or something. I suspect that that filter will clog quickly so don't run it if you're not around to check the pressure and backwash. That filter doesn't have a recirculate setting so you'll be filtering when you run the pump.