Many of the chemical tests should be done with the water closer to room temperature. They are designed to be measured at those temps (70-85). You can just let the water remain covered in its container sitting at room temperature until it warms up. Then do the test.

If the water is cold, then the CYA test will not form a precipitate as quickly in 30 seconds. If you let the water warm up first before doing the test, then it should be fine.

Richard