New LaMotte Phenol Red TesTabs for PH

We’ve spent the summer trying to figure out our pool chemical situation. After running out of PH tabs in June and not recording the product information, we’ve ordered the wrong thing and tried a variety of test strips from the local hardware store. We now have LaMotte 3880A Instrument Grade TesTabs for ColorQ, PH (100ct) and they seem to work OK with one exception: they take about 4-5 minutes to completely dissolve.