I analyzed all of my data from my experiment and I calculated the difference in Na, Mg, and P from the top of my samples vs. the bottom of my samples. The Mg and P have small differences in the samples with no MgCl(sample 1) and 50 mM MgCl(sample 4). They have much larger differences with 5(sample 2) and 10 mM MgCl(sample 3). The Na has an odd trend.
Here are the graphs of Sodium 589.592, Mg 279.553, and P 178.221. When finding the differences, I took the absolute value. The error bars are too small to be seen. The y axis has units of mM.