RedSea Magnesium Pro Reagent Refill Kit
The reagent is identical to what you received in your Reef Foundation kit, it is just a larger volume to allow for more tests. Most likely the reagents you may have had were getting old and possibly slightly contaminated from air contact. If you have another test kit or LFS to give you a second opinion on the different readings that would be preferred to know which result is accurate. However with magnesium in the range of 1280 – 1400 is totally fine and no ill effects should be noticed in the aquarium.
If you feel that something is not right with the reagent refill, just reach out to us at firstname.lastname@example.org or 763-432-9691 and we would be more than happy to help you out.