I went to the local Home Depot to see if they had any Sonotube. What I found was Quikrete Quik-Tube. This tube I believe was around 1/8" thick or maybe just a bit more. Is Quikrete Quik-Tube the same thickness as Sonotube? The largest diameter they had was 12" and I think I need 14" to fit a Shiva into (unless it can be done with a 12" diameter tube). It just didn't look that thick as compared to my SVS subs.