Many thanks! Is that an ok reading?
Also how often should I change the liquid? The box said every 2 to 4 weeks.
It's right where you want it, but watch your fish to be sure.
I'm not sure how often you'll need to change the liquid. I'm guessing you won't have to change it that often. I just started using one about a month ago, and I plan on changing it when the color starts to fade. I don't see any reason to do it sooner.