What is her overall budget for this project? A pond that size, the filtration system your describing will be expensive. The material they used will breakdown over time and the use of a skimmer will be pointless because the seal will fail. That type of material doesnt like freeze thaw very well and then you add the sun to it will become brittle and crack on the exposed areas. I personally would setup the area as natural pond using a bottom diffuser and a surface areator for algae and duckweed control. I wouldnt even bother with a skimmer.
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