Would there be much of a cost savings to having a disk with just 4 parameters? The cost of the disk is a major hold-up for many interested and if the film cost is a significant portion of the disk then maybe a limited disk would help with the cost. I think these params would be great on a lower cost disk: pH (needed for Alk) CO2 (needed for Alk) Temp (needed for Alk) Salinity (needed for Alk) How much (if any) of a cost saving would there be with this limited disk? Even though this is essentially just 1 parameter (alkalinity) I think this is what 95% of the supporters are looking forward to. I understand that having at least 10 parameters makes justification of the cost easier but an alkalinity only disk would be great if it could be about $10-20 instead of $30-50 for the full blown disk. I am personally only buying the Mindstream for the alkalinity monitoring.