Looks great,
FWIW spa-flex should not be glued. It wasn't meant to be glued. At least that's what they told me at the plumbing supply place by my house (they've been there for 50+ years). A friend who is a master plumber (not Ronen) said in spa use it's joined with hose barb and that all flex hose should be joined with hose barb. He said the manufacturer also does not recommend using glue. Just food for thought. FWIW Ronen concurred with him that spa should not be glued and when it's used in a spa setting it was always joined with hose barbs. The reason being that the "glue" or solvent will not bond properly to flex pvc. It's not the same material as regular pvc, it's also not glue but solvent. Since the two different materials cannot be solved together like regular pvc you do not get a true weld. The ridges of the flex pvc also prevent a true weld between the two pieces.
The angle at which the spa is after the union on your return line looks like a recipe for disaster.
Not trying to hate just trying to help you avoid a "leak" thread
Where's the full tank shot?