If your tube filled up, it means you have less than 20 ppm of CYA, and you need 60-80 for a SWG.
Using the pool calculator, determine the dosage to raise your CYA to 60. Add that in your skimmer, and don't backwash or clean your filter for a week, while it dissolves. Then retest. You can always add more, you don't want to overshoot.
To me, there is an inconsistency in your numbers. You show CL 5
cc - 0 and
You buy CYA aka Cyanuric Acid or at Walmart and pool stores might be labeled as Stabilizer.
Use the pool calculator to determine your dosage based on your pool gallons (I don't know what your pool size is) and then put it in your skimmer and let it dissolve in your filter, could take up to a week to fully register the total amount on a test. That's why you don't want to clean or backwash a filter during that time as you will lose CYA you just put in... Always under dose, you don't want to overshoot and then have problems resulting from CYA that's TOO high.