I ended up getting my big shop vacuum and using it to pull the old sand out. I was careful to not suck up too much wet sand at a time before emptying the shop vac. It could hold 50 or 60 pounds but I would not be able enough to dump it out. Anyway, I got the sand all out in a fairly short time.

I cut up a bleach bottle to make a scoop to get the new sand out of a bag and I scooped sand out of the 50 pound bag until there was about 15 or 20 pounds left in the bag and then I lifted the bag and poured. Yes, I had tape over the center pipe opening. I put about a foot of water in the filter tank before starting to pour the sand in.

With all 250 pounds of sand in the filter tank, I put the top valve assembly back on, switched the valve to backwash and started the pump. When the view glass seemed completely clear, I switched to filtering, and now a lot of filtering and Kreepy Krauly work has to be done as I had killed off some green algae and the pool bottom was coated dark green.

Now I have a question. I am considering putting a liquid cover on the pool to help it save heat. Is that stuff going to foul the filter? Perhaps I shouldn't use it? Please CARL and any others, what do you think?