I had a couple separate gallons of ESV calcium in my bin. One of them is partially full, about the same level that it comes shipped in before you add RODI. But I forgot if this particular bottle has already been mixed or not. How can I test it to see if it’s the concentrated before RODI added or if it’s a bottle I’ve already mixed and used some out of? Matter of just using a chem calculator with a sample of tank water after and checking results?