3" to 1.5" reducer attached to 1.5" PVC to reach the sump, about 8ft
1" male with weirs cut by a rotary tool screwed into 3" to 1.5" reducer.
shortened old J tube for siphon from window tank to reducer.
3" dia PVC tube with a cap on the bottom cut length to just under the rim of planted sump tank.
put gravel in tube for stability.
Water enters the planted tank from my 150 gal, over flows into a 50 gal sump.
Been running about 3 days without incident.