Copying this from another post from a user who asked the same type of question you are asking...
Originally Posted by fishballer06
Obviously we all know a Shocker works great with a standard output tank (750-850 psi). As of lately, I have been running my Shocker's on the Ninja SMP tank (550 psi output) and they seem to run great with that, and allow me to dip into the tank a little further with the slightly lower output pressure. I have also done some testing with the Ninja SLP tank (275 psi output). While the gun does still work properly, I have noticed that my numbers over the chronograph will have a slightly higher spread. Say one of my Shocker's is shooting +/- 4 fps, with the SLP I will get around +/- 10 fps on the same marker. Not that this is a huge deal, but is just some solid numbers for everyone to relate to.
You're better off using a different reg than the SLP, but it will work in a pinch.