FloPure Water Softener

Hello Old Biscuit. Are you out there somewhere? I have another question about our water softener. The instructions say to do a back flush twice a year, feeding water into the outlet and out of the inlet connection at a rate of one gallon per minute. However, it doesn't say how long to back flush. Can you help?

We are regenerating the water softener approximately every six weeks and it is working better than we had hoped for. We love it!