Aside from your abraded leaks, I wonder if your valves are leaking. I'd suspect valves first, which is one more reason I was so surprised at having lost no air. Mine are from NRS, as per Yost's suggestion.

: I have been using the clear vinyl from Walmart and think it is time
: to try something better. Heat Seal appeals to me bu it is rather
: pricey so I think I am going to try the tarp material.