*If* you kill it,
*And* you have no circulation,
*Then* it will tend to settle out over a few days time.

What is the goal here? Are you wanting to get a head start on summer? Avoid having the slime 'eat' your stabilizer? Those are possible, though it may already be too late for the second.

Or, do you want your pool to look nicer, even though your pump is not running? That is pretty iffy. Floc -- alum -- might help, or you might make a mess. Poly aluminum chloride, in a number of the liquid flocs, is easier to work with (ie, less likely to make a huge mess), but it's no slam dunk.

It's your pool, so you can do as you like. If you do decide to use floc, follow the directions VERY carefully. And make very sure the algae is DEAD first. Nothing flocs live algae.