I was going to say the same as Innovator... granted, 7 isn't between the normal 8-12 that's normally recommended, but it's pretty darn close. Probably well within the accuracy range of our test kits. My tank comes in at 7 at the end of the day often. I'd like it to be higher, but I'm not seeing any issues or problems, so I just let it do what it wants to do. For my 46g, I'm dosing 20 ml of both A and B per day. Calcium stays at 410-ish and alkalinity hovers between 7 and 9 dkH.
If you're not seeing any issues, I wouldn't stress about it. Shoot... maybe get a different test kit and you'll get better numbers!
