Like most Red Sea Reefer owners I was also using 1/2" loc line to split my return nozzle not only to aim the flow to different areas of the tank but to stop the sand from getting blown towards the back of the tank.
@TSA makes a custom 3D printed Loc-Line Adapter for the Red Sea Reefer tanks so I decided to try it in hopes that I gained a bit more flow out of my return pump since their adapter is for 3/4" Loc-Line. Im not running the pump at 100% so I can still increase the speed to get more flow back to the tank but I know the "U" in my manifold is creating a lot of head pressure so Im willing to try anything to reduce the head pressure cause by the "U" bend. By installing the 3/4" adapter from TSA with 3/4" lic-line I gained a little over 250 l/ph from my return pump still running it at the same speed.
Over all Im very pleased with the results and very happy that I switched the adapter and loc-line to 3/4".
I highly recommend that if you have a RS Reefer you give this a try, totally worth the extra money.
Link to product:
http://topshelfaquatics.com/product/red-sea-reefer-lockline-adapter-nozzle/
Here are a few images of the adapter and loc-line installed on my Reefer525xl.

Reefer 525XL -3-14-2017-6 by
Reefer525XL, on Flickr

Reefer 525XL -3-14-2017-8 by
Reefer525XL, on Flickr

Reefer 525XL -3-14-2017 by
Reefer525XL, on Flickr

Reefer 525XL -3-14-2017-3 by
Reefer525XL, on Flickr

Reefer 525XL -3-14-2017-5 by
Reefer525XL, on Flickr