Alk is related to pH, and while 8 is on the lower end of the spectrum, I don't know that it would be that high with a pH of 7.4. Two years is far too long to go without calibrating. I think most manufacturers recommend calibration every six months... if try calibration and testing again before you start changing/dosing things.
If your pH is at 7.4 and calcium is at 200ppm its kind of odd that your Alkalinity is at 8.0
Anyway, if your parameters are really all out of whack and you cant figure out why, where, when, or how; you should seriously consider some frequent slightly larger than usual water changes with nice fresh new mixed saltwater using high quality reef salts.
Thanks for your service. I think I may also need some better test equiptment! I'm using API kit, I was told that it is the most inaccurate kit on the market!