UPDATE: I was able to stop the bubbling by tilting the case on its side to move all the air to one corner and filling it over and over until the return line was submerged. It's pretty simple but if you want to see a video with that let me know in the comments.
A follow up to my distrocase 350p video. If you have any questions let me know in the comments, thanks!
Original distrocase video: • Thermaltake 350p Distrocase unboxing and t...
Part list: https://pcpartpicker.com/b/c3GcCJ