Okay I need to backwash to waste, but I am not sure if the I have a "main drain" line. In the past I've just plugged one skimmer and used the other and vaccumed that way. Now I've searched and found that some recommend closing the "main drain" valve, where the heck is that?
I bought my house several years ago and the pool came with no manuals or anything. So I've been searching, hiring pool companies, using pool school, and yes, winging it sometimes with the functions of these parts (chlorination, cyclonic ball valve, sand filter, and pump). I'm including two pics so you can see what I mean. I have a ball valve, but I'm not quite sure how to use it. Thanks a million!