Has Instant Ocean's magnesium level changed?

[Bblinks]

I checked the params with salinity at 1.026, temp at 26'C, using red sea and salifert kits and came up with 420ca, 10dkh, and 1350 mag. I know it sounds too good but that's what I got from both kits, well close enough. Last batch I checked was a few months ago and it was low in calcium, it was around 380 and the only thing I changed was instead of buying buckets I started to buy 200 gallon boxes. Weird?! I guess I better start to testing every batch again.