Planted Tank Enthusiast
Join Date: Apr 2012
Location: Edmonton, Canada
The average CO2 canister, be it a 5lb bottle or a PB canister has about 800psi pushing on the top. That PB valve is an on/off valve, never meant to regulate the 800psi coming out of the bottle. So that means the needle valve and anything else connected into that line is running at 800psi pressure.
This is completely my own opinion so you can do whatever you like. But I prefer to be safer than sorry, I use a regulator.