Hi John,
Sorry for the delay, however keep in mind that the kits were not received until last week, however the agreement was made on 2/12, so it hasn't been a month and a half since we have set on them.
I just tested both kits, and found both of them to be accurate. They both registered just over 1200, while my Salifert kit was reading at 1220.
I can send one back at no charge, however we are unable to refund both of them since they have been used. I had to use some Mg titrant from another kit to test with, as it looks like you did not send these bottles back. I will have the one kit that is most complete that you sent back out the door for you today, in which you should have in just two days. If you have any questions when using the kit feel free to drop me an email or give me a call and I"d be happy to walk you through it.
Thanks,
Jeremy