Replacing a Return Fixture- Sizing and Aiming Questions

[Juvenall]

For the last few weeks, I've been battling my pool's cloudy blue water with slow success. In my research of the subject, I heard a lot of people mention part of the problem could be the flow created by the return fixture. The pool as it stands (since I got it with the house a few years ago) doesn't have one. It just shoots straight out.

So I'm thinking I should grab a replacement part for this, but I'm unsure as to what size of an opening I should pick up. Once installed, what's the suggested way to aim in since I have a main drain in the center of the pool?

My Pool's Setup
21' 10,500 Gallon Above ground round.
Return 4 feet to the left of the skimmer (when facing it)
Main drain in the center of the pool.
18-inch sand filter w/1hp pump (all new this season)

 

[JasonLion]

Large openings are more efficient but produce less water movement. Generally you can get enough movement with a 1" opening, so try that first. The return should be aimed hard towards one side and just slightly up or down (always down without a main drain). If required, fiddle with it a little until you get a nice circular motion of the water in the pool.

 

[Juvenall]

Thanks, Jason! Did just that and I have a very solid circular pattern going on right now.

I think the question now is do I face it towards or away from the skimmer? Right now, I have in order from right to left as you face them (and about 3-4 feet away from each other), the pool ladder -> skimmer -> return and the new fixture pointing away from everything else. It does sorta seem that the pool ladder is breaking the circular motion and diverting some of the now being kicked around, but I'm not sure if that's a big deal or not.