Pool Shop I Have An Above Ground Pool With Hayward Sand Filter. When I Backwash It Starts Out Fine Then Stops. Help?

I have an above ground pool with Hayward Sand filter. When I backwash it starts out fine then stops. Help? - pool shop

I opened the pool last month. It was not clear from the outset, but the bank told me that my group of chemicals on the right side. I just hope the hangover before it stops working. Rinsing is the same. It starts well and then shut down until it stops. Please help.