Would you trust this machine to provide baseline and trends for your tank?I'm not familiar with this particular machine, but if they use color disks, then almost certainly it is measuring carbonate alkalinity (by pH and CO2, like Mindstream was planning to do) rather than total alkalinity (which needs a titration of some sort).
The difference is small if borate is not unusually high, but they are not identical. Carbonate alk is lower than total alkalinity, mostly due to borate alkalinity.

