Agreed, call them back out and have them do the job right. A liner that is exposed to the sun will deteriorate faster and be more prone to puncture.

See this current issue of Pond Boss Magazine for an article by Mike Otto on doing a pond with a liner.

www.hoosierpondpros.com

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).