Yes, it is normal for a multiparameter device to take time to provide stable readings for dissolved oxygen. This delay occurs because the sensor needs to equilibrate with the sample's temperature and environment, and electrochemical sensors require time to stabilize. Factors like water flow and sensor condition can also contribute to the delay.

Hey, Carlos. I highly recommend that you move from galvanic type units to using optical sensors. They respond much faster and are easier to maintain and calibrate than the old membrane type sensors. Also, if your project requires you to measure low DO waters, these optical sensors actually perform better the lower the DO gets! They cost a bit more, but the time savings and the better quality data you get from them make the expense worth it. Good luck with your project!