Hi there, sorry your having persistent liner problems

Many liner pools have sand and cement bottoms and don't experience the rapid degradation that you describe. However, the Kreepy may be responsible, is there a way that you can make it's suction less aggressive while still allowing it to clean the pool? (Like leaving another suction port slightly open - I have very little experience with Kreepys so can't remember if there is a relief port for them)

Vermiculite and cement is a softer mix for the liner, but I doubt it's something you'd want to try to apply yourself as a 'skimcoat' If the floor is uneven or has sharp ridges or protrusions, you'd certainly want to address those areas!

You shouldn't have any trouble with a liner drop where you are (I installed a liner today with the air temp ~53* and little sun - it was 'tight as a bowstring', but went in fine ) Temps over 60* and full sun help a lot, but they can be done even when conditions aren't optimal.