Return pump help

[Everclear]

So, I may have been out a little late last night and I just can't seem to wrap my head around this. I am setting up my new Waterbox 10 cube (absolutely love this little tank) and I want to upgrade the returm pump from the anemic 80 gph stock pump to a Sicce micra plus (158 gph). Here's where I'm having difficulty, the outlet on the micra is 3/8, the nozzle on the waterbox is 8mm which i believe is 5/16. How do I reduce the 3/8 to 5/16 so I can use the micra? Sorry if this is obvious but my brain has gone all fuzzy. Any help is greatly appreciated. Thanks!

 

[Snoopy 67]

Use a 3/8 hose, wrap the 5/16 nozzle with plumbers tape & clamp with a plastic clamp.
Amazon product ASIN B09QLYRYMY

 

[PharmrJohn]

If I'm reading your issue correctly, it may be just as simple as using a schedule 40 or 80 PVC reducer from 3/8 to 5/16.

 

[Everclear]

Those are both excellent ideas, I figured it would have to be something simple. Thank you!