I found the source of my leak. The tank has a hairline crack down the back of the tank. I think I want a WRX alluminum one since the plastic ones kind of suck. I am going to try to patch the crack temporarily or bypass it until i can find another tank. Any info on how to do the bypass would be helpful.
There isn't really a way to bypass that, since that's where the pressure cap is.
On mine, JB weld has been holding up surprisingly well. Just make sure you clean the area very well, scuff it up and make sure it is completely cured before re-installing.
Disclaimer: If anything I post is inaccurate, please correct me. I do not wish to add to the misinformation floating around on the internet.
That being said, everything I post is accurate to the best of my knowledge.