yeah, they're pretty accurate, i keep one extra hydrometer on hand just to occasionally check the rh in my coolidors/otterbox... as long as you have 1 hydrometer and use it to make sure the beads are keeping the rh, you shouldn't have to get a seperate hydro just for whereever you got your beads, but it couldn't hurt. by the way, go post an introduction so we can know who you are.