5 lb CO2 Tank Survey

I'm pretty sure Rex's tubing is Neoprene.
 
I like rex's tubing because it's so much firmer than the silicone and fits VERY tightly at connections too.
 
I bought a kit from Red Sea that had everything in it. They say that the tubing is special CO2 tubing to minimize leakage. It came with the Teflon ring. If I was having a slow leak somewhere, would I see it with the soapy water? Does everyone only use the Teflon ring, or do you use tape and the ring?
 
AquariaCentral.com