To clear the pool, you need to keep it at shock level which with a CYA reading of 50 would be 15ppm. So, yes, you need to add more. It's ok to use up the 12.5% first. I gave you reference amounts in the previous post so you can figure out doses to add whenever you test to get back to 15ppm.

Another and less expensive option instead of the full K2006 kit is to just buy the add-on kit called the K1515. That would give you the test that your kit is missing which allows you to be able to measure chlorine levels past 5. It is also available through that same link posted above. It will make it a whole lot easier to manage your pool if you can test levels more accurately.

Keep an eye on your pH. You are ok at 7.2 but if it goes any lower, you should bump it up a little by using some of the Borax. Add about a half a cup at a time and then several hours later, retest and redose until you get it where you want it. Anywhere between 7-8 is ok with the mid 7s usually best for most pools.