Well, I figured at some point I should tackle this sometime.
Well, we got lots of rain yesterday afternoon and evening. So much that I was over the top,of the skimmer box, almost to the coping. Great, I can backwash and play with the "extra" water
I gave the filter a good backwash and got the wet/dry vac out because my sand filter is installed in a "dry" area under the house. I won't be able to just push a hose in a nod let the water run out.
I closed off all the valves as my pump/filter are much lower the the pool, released pressure on the filter and openers her up. I put a hos in and began siphoning the existing water out of the filter.
When the sand came into view it was a wonderful sight. Smooth clean white sand like a beach in the Bahamas. No much, no channeling soft and loose.
Wow, that was easy.....
Put the top back on, fired up the pump and purged the air.