I use a Color 2X PRO 7, and the LaMotte WaterLink HOME Solutions APP, to test my water on a daily basis. What is the difference between Alkalinity and Adjusted Alkalinity measurements? Should I use the alkalinity number or the adjusted alkalinity number, to maintain the correct alkalinity level in my pool? My current numbers are 142ppm alkalinity and 100ppm adjusted alkalinity with pH at 7.3ppm. The report indicates my alkalinity is high. Thank you.

First let me make a point, regarding pH and TA. pH is ALWAYS the more important of these two parameters. It may not be always possible to get both in range, at the same time. If that is the case and the pH is in range, there is no compelling need to lower the TA, if it is high, providing that the water is clear and there are no signs of scaling. Accepting this will spare you the endless raising of the pH, which results in the TA rising too much. Raising or lowering one always affects the other, in the same direction.

Traditionally TA is based on bicarbonate-carbonate alkalinity, but other dissolved salts, such as cyanuric acid, can affect the TA. For this reason subtracting 30% of the CYA reading, from the TA reading, will give a better estimate of the bicarbonate-carbonate alkalinity.

Based on the data provided, the difference between the two TA readings can be accounted for by a CYA reading of about 140 PPM, which you did not provide. In your case, the available alkalinity is within the typical 80-120 PPM range and the pH is within 7.2-7.6, as well. Relying on the unadjusted TA, would lead you to think that an addition of acid, to lower the TA, would be beneficial. The addition of acid will lower the pH and force you to add soda ash to raise it back to 7.2-7.6. This will raise the TA and bring you back to the same place you were, before the acid was added. Avoiding this unnecessary up and down is the point of what is stated, in the first paragraph. I would rely on the adjusted TA reading and not add anything to alter the TA.  I hope that this is helpful.