How to remove this?

[AndyT86]

I opened my Hayward 200 sand filter to see how the sand has held up over the past 7 years because I have never done anything to it. According to the user manual, this is called the top diffuser. How do I remove it? Does it twist or screw off? Is there a release of some sort? Will the sand be higher than the connection point? Do I need to remove the long plastic tube, too? Is there anything I need to look for when removing either?

Just wanting to be cautious and not break anything.