found it! This is from a salifert rep on another board.
Important information on two batches of Alkalinity kits
A very limited number of the KH/Alk kit reagent KH have very likely been contaminated in such a way that it would give a high false value.
Each batch consists of several thousands of bottles and the best possible estimate is that only 10 - 50 bottles out of a batch of several thousand have been contaminated.
So only a very, very small number of reagents (but yes, even one is too many
The two batches very likely affected are:
1106-C and 1106-F , the batch number can be found on the label of the large KH reagent bottle.
Most of the contaminated 1106-C were, luckily, already returned before even getting to the end user, very recently.
I also think that most of the contaminated 1106-F have now been located.
The nature of the contamination would be such that a limited number of bottles as a group would be contaminated untill the contamination would be exhausted.
This also shows that there was or is NO batch related issue, that is a whole batch being bad.
We have taken measures so that this, very difficult to find cause, can not happen again.
To give you an indication, we received a total of approx 45 requests for replacements in the past period. This demonstrates, also given that Reefcentral is a very large board, that the number of contaminated reagents is indeed very, very small.
Besides that the number of 45 requests also is in part from people who were unsure and since we did not have the information we have right now we did also honor their request.
I will now have also more time to concentrate on some other questions such as some differences between different good batches/good reagents. Most of them can be explained by the accuracy and precision and the value range used for calibration. However, I'll start tomorrow another thread about this last paragraph.
Please allow me to give you all a very big thumbs up because most if not all of you were and are very polite, very patient, did help me further by answering questions, did try to think together with us and came with many suggestions. I’m very, very proud to have you as a customer!