Just getting into the TF100 kit I recently ordered & was doing the calcium test today. The card said to fill to the 10 mark but I saw a video on YouTube where they fill to 25? Reason I ask is because after testing at 10, the red/pink color never seemed to definitively turn blue, just noticed a lot of floating red/pink particles with just the slightest hint of violet. I live in Phoenix & the water here is real hard, just wondering if I’m doing this test right? I’ve got the Speedstir, will use that next time. Thanks again