I apologize in advance for the idiotic question. Here is my filter. It's a Pentair S7M120. I need to drain my pool to lower CYA. However, the valve that I thought was the one to use doesn't want to turn. Is this my drain valve? (In the lower front of the photo) It's labeled "Waste".
On the side, there is another valve, to one direction it's labeled "skimmer", and to the other direction, "main drain".
Thanks in advance... appreciate the help.