Desperate need help for upgrade light fixture
 

I have a 36" Aqualight Pro with 150W metal halide. I was posting up for sale about a week ago, but now I want to keep and will upgrade it instead. But I have no clue how can I change from 150W to 250W ? I know it needs to change the ballast ... but how about the rest ? Do I need to change to a new DE socket or can I just change the bulb ? How about wiring ?
Pleaaase help ! I have no idea what to do with this fixture.
I woulb be thankful for any advice.

The 250w socket is bigger than the 150w socket. You'll have to change it out.

Million thanks for your quick advice.

Does anybody have any experiences as to how you can upgrade an Aqualight Pro from 150W to 250W ? Now I know I'm not only need to change the ballast but also need to change the socket as well. When I open up the fixture ... Oh boy ... look inside it just like a puzzle game for me. Please be kind enough to share your knowledge if any of you know how to do it.
Thank you very much.