Fluval T5HO fixture and adding griplock gliders

[pk-sd]

Anyone know how to remove the top cover of T5HO lighting fixture? I am trying to add griplock gliders on it. Do not like the hangers that come with it, as I can't think of way to make height adjustment as easily....

Thanks
PK

This is what comes with the fixture:



Would like to install these:

This is the Fluval fixture: