https://www.youtube.com/watch?v=8kSLISHGwfY  Check out this genius servicing a MH well light . I wonder how long it took him to figure out his mistake !!    GEE , I wonder why the comments are turned off ? 

What a hack, let’s see hmm:

1. Took apart the ballast assembly for no reason.
2. Removed reflector so now the light goes nowhere.
3. Basically calks the thing shut.

I’m disappointed in humanity.

Yeah, I'm not sure why they took apart the ballast assembly unless the lamp didn't strike on initial test. And yeah the missing reflector means this thing will put out a lot less light.
Not sure about the caulk too, aren't those things supposed to be sealed well enough to not need it. That's gonna be a PITA for the next person to service this to deal with. 

In his initial comments. He wrote that he removed the ballast to verify that the lamp matched the ballast . As for the caulking , about 1/2 way thru the video you see him cleaning off old caulk from the lens and the retainer ring .

 What I saw :  1) He never reinstalled the reflector . I'd bet that SUCKED to re-install AFTER he caulked it closed !!
               2) He didn't clean the lens before re-assembly .
               3) The new lamp looks to have a much bigger arc-tube than the original so either the original was an incorrect
                  lamp OR the one he installed was wrong ! Original looked to be either a 70 or 100w MH , new appeared to be 
                  150 or 175w .
               4) He never tested the fixture before re-assembly to ensure it actually worked AFTER his repair ! 

 I found it much easier to watch this once I slowed it down as much as possible . It playing so fast that you miss things at full speed !!