I have a Hayward Pro-Grid Vertical DE filter. Both locknuts connecting the Multiport valve (SP0715XR50 2" NPT) to the filter body are cracked. I would like to replace using 2" split nut unions, as previously done on another fitting, however the treads on the Bulkhead fitting (DEX2420FB) are much finer than on the previously repaired connection. Is there a 2" split nut union with finer threads?