CPM,
I had bought the standard solution to try to practice getting the correct CYA as well. My standard solution worked GREAT right out of the gate after I bought it. However a month later, mine acted like yours and I could not get it to cloud up. My conclusion was to trust myself and just start testing the CYA using the methods posted in Pool School. By adding some solution, and then peeking quickly at the tube to see if I can see the dot, it seems to work great for me. As soon as I cannot see the dot with my quick glance, I record the CYA value and do it again. I repeat it by pouring the liquid back into the squeeze bottle, shaking, and then repeating the test. If I get the same answer twice in a roll, that is what I use for my CYA.
Good luck! The CYA is the hardest and most subjective of the tests. Just trust yourself and repeat to verify.