I found a couple of leaks on this new build. One is located at the elbow near the bulkhead and the other located on the ball valve. The ball valve leak was an easy fix, turns out I forgot to glue it on one side (DUH!!!) ... the leak on the elbow I used flex tape. Problem solved. At least for now.
the way i would do it as a permanent fix is to prefabricate a new piece with a bushing in the 90 elbow and everything glued to a new union. my most recent setup is very intruquite, i'm a pipe fitter laid off due to the virus so i'm pimping out my coral tank plumbing