I purchased a new set of Salifert test kits from Drs. Foster and Smith last week to test against my Hanna Checker's because I felt there were off based on the color of my corals. This morning the Salifert alkalinity tested at 8.3 (expiration date 9/2018) and the Salifert calcium tested at 405 (expiration date 12/2018). The Hanna Checker for alkalinity tested at 7.62 (expiration date 8/2014) and the calcium registered at 489 (expiration date 11/2014). Which test kit should I believe is giving me the correct results?