Just purchased the API reef test kit. I have read somewhere before and have noticed again that the 5ml line on the test tube is not really 5ml. I put 5ml in my syringe and put it in the test tube,and it is approx. 1ml over the line. In other words the line is about 4ml. Which with Kh means it's off by that much. So. 7.5Dkh on the test tube line that says 5ml and 10Dkh with the actual 5ml in it. WTF? Anyone know?