I'm not going to get into the rest of this, I just want to comment on safety when storing chlorine.
Get the SDS, read it, understand what you are reading. Go look up the rules regarding what it can and cannot be stored with or near. Read up on the consequences for failure.
Chlorine is both extremely toxic and extremely corrosive. Solid forms do break down over time and release gas, even when "sealed" that gas does not care that it's in a container, it will continue to build up until all the solid is gone or it reaches the point where the pressure stops the phase shift. For chlorine gas that is enough pressure to generally break a plastic bag or force its way through seals not meant for compressed gas. Keep in mind, it will EAT most materials you'd use to seal it, so if you want to contain it you need the right stuff.
Storing gaseous clorine, such as a compressed gas cylinder from your local compressed gas supplier, is not as easy to do right as you'd think. It must be stored well away from flammables, oxidizers and inhabitied buildings. It should be protected from the sun and other heat sources. It should not be near any source of ignition. Oh, and if it starts leaking, you need specialized gear to safely handle it, not just a filter mask and gloves.
To really make for a fun day, it is a reportable quanitity and extremely hazardous material even in a very small cylinder. Depending on your situation that may not require any additional paperwork, but if you're setup as a business it will, even if it never leaks. The EPA and other agencies aren't real big fans of the stuff, for good reason. I'm in the business and I just finished getting rid of all the chlorine (and some other stuff) that we had on site, it wasn't worth the hassle. Now when we have a customer for it we get it from our supplier and take it direct to the customer. Empties and partials go directly from the customer to the supplier, never coming to our facility. That hassle was the better choice than the risks and hassles associated with having it in our facility.
Your best bet is literally SCBA gear, you want your own air supply. You also want air flow away from you because it will rapidly damage metals and other parts on your air system (not to mention you). I would bet you have very little actual chlorine left, probably just ambient pressure, but even that will kill you if you got a lungful or two.