What can influence a tank's Mg reading

[Myka]

You don't mix your salt for 24 hours? Maybe you aren't mixing good enough...

That's why I never bother with a premium salt. Every once in awhile I get lured in, and buy a bucket or two, but I always end up going back to the IO because I see no difference in my tank, and I don't find dosing to be very expensive. I worked it out that using (expensive) liquid supplements, supplementing an entire bucket of IO costs me less than $16.