Well, the DC gives you a nice quick visual reference, even though it isn't very accurate. Many people, after they become more experienced and learn what to look for in the tank, don't bother using the DC after a while. It's really up to you. I mention these things so that you have more options. It's good to compare the two, while also observing the plants and fish, so you can relate all these indications together and to have a better confidence and knowledge.
Cheers,
Cheers,
