Yes, it might drain back if it gets air in the line or if it leaks by the pump. The pump should be rated in feet of head which should tell you if it can pump that high. The drain back during off cycle is another matter. Maybe a foot valve / check valve if the pump won't hold during off cycle. The loop won't help though, it will siphon everything in the line back anyway.
Any evidence of overflow?

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Jim Luttrall
Mr. Inspector.net, Inc.
Allen, Texas 75002