If youre set on salvaging your existing setup, yes, sucking glue will work on the Suction side fitting.. (great trick if you've gone cheap initially, and not used a Union.. ) but glue will not suck into the pressure side. Your best bet is to get some strong EXTERIOR silicone caulk (clear), and completely, thoroughly coat the threads on BOTH the Union fitting, and the Pump threads, then assemble, and tighten. Be sure to let the Caulk dry for at least 24 hours, preferably 48 or more, before turning the pump on. If you become impatient, and turn it on before the Silicone is completely cured INSIDE the threads, as well as out, you will be doing the job again. Personally, I'd probably try to RMA that thousand dollar Pump, especially if it's a manufacturing defect.. QA Personnel miss stuff on the final checks on ocassion.. you could then start again with fresh everything. Good luck ..