Kywildcats:
One last item. When you open the pool, because the black plugs are on tight, it may be best to use large pliers. I carefully go down with goggles (you have to lay down on the patio) and apply a little pressure (counterclockwise 1/2 turn), and you should then be fine. You will understand once you turn as the "feel" is there. This is helpful so you do not snap the plastic. My steps (plugs) are inserted a bit inside. Each year, I have to use the pliers to pull out slowly. Next year, I will order larger black plugs.
When the tight seal is broken and the air comes out, it is very easy to pull the rubber plug out. The threaded ones, in my opinion are dangerous if they are over tightened. Although, some people have success with them. I did not.