UNDERLAYMENT. After laying and trimming some old carpet pieces to use as my underlayment I am not totally happy with the material. It appears to be very bulky in places and I'm not sure if it will take away from the volume/depth of the pond area. I did get the carpet pieces free from a friend that was remodeling his floor so that was the best part: FREE. The other problem I have with the carpet is that it has this real pungent old used smell to it. When I was laying it down I did find 2 sewing needles in the carpet fibers. This has me very concerned with possible leaks by a puncture into the liner. Should I vacuum up the carpet where it lays and try to vacuum any potential hazards in it ie needles and is there something I can spray on it like Febreeze to make it less funky. Should I go with an online underlayment material for ponds but I'm probably looking at $75-$100 just for the underlayment which I would need a piece 16' x 21" not including shipping. Whereas that's money I could be using on a new pump instead. Is there any other thinner material I can use and find somewhere like an arts & craft store like Michael's etc. Any suggestions would be great. Thanks