Knowing when to change your carbon blocks shouldn't be a mystery! Learn how to identify when your carbon blocks truly need to be changed in this episode of BRStv. Knowing how to test your carbon blocks performance is really important in ensuring the highest water quality output. Rather than relying on a visual or monthly change-out of carbon blocks, there's a simple test you can do to truly know when your blocks have been depleted. Here's how: For this test, you will need a LaMotte Total Chlorine test strip, which will read both chlorine and chloramines, Step 1: Run your system for 30 minutes. Step 2: Take a sample from the waste water line of your RO system. Step 3: Test the sample using a LaMotte Total Chlorine test strip. If your results come back as 0.5 or above, I would recommend changing your carbon blocks.