High pH problem

So I've been adding kalkwasser to my top-off water to keep my calcium etc. up where it should be, as well as vinegar to help keep the pH from getting too high for almost a year now and it had been working ok for me, up until recently.  It seems no matter what I do, I can't keep the pH from soaring after the lights come on. Every couple months I will totally empty the reservoir and clean it out so the lime water  mixture doesn't get too strong and that always seemed to solve the high pH issue, but not this time.......I never turn the pump in the reservoir back on until the kalk has settled etc and the pump itself sits about an inch a half off the floor of the reservoir so that it doesn't pump the super concentrated kalk stuff into the tank.  Any ideas what I should do?  I've thought about a calcium reactor, but I don't know if I want to get into that if I can avoid it.........

 

It's around 8.5 with the light off, then creeps up to about 8.8x at the highest......strangely, none of the inhabitants seems affected at all by this. Its a gradual increase, so maybe that's why, I don't know. I usually add a little vinegar to the sump when it starts to gets really high and that will bring it down a little bit for a little while.

 

I don't know what magnesium is at (the test is a pita /DesktopModules/ActiveForums/themes/_default/emoticons/smile.gif) but my alk is about 3.5 meq/l.

 

Its a pH probe hooked up to an AC Jr. It was calibrated, ahem, about a year ago /DesktopModules/ActiveForums/themes/_default/emoticons/unsure.gif  How often should it be calibrated? 

 

I'll check out the calcium and Mg and see what they're at. I was going to do that, but figured I'd ask here first, since I wasn't quite sure what each one would mean if one was out of whack......

 

Ok, re-calibrated the pH probe........it's at 7.94 /DesktopModules/ActiveForums/themes/_default/emoticons/sad.gif I did a pH test with chemicals and it came out to about 8.0 too, so I think the pH probe is accurate. Seems like all the vinegar I've been adding has actually been working-too bad I had no idea it was already low enough.   I hope in a few days things will even out, we'll see. I'm going to see what the calcium and magnesium is at next, but am watching the kiddos so hubby can watch his precious "Lost" tonight uninterrupted, lol /DesktopModules/ActiveForums/themes/_default/emoticons/rolleyes.gif

 

So I added a bit more kalk to the rodi reservoir  to make up for the lower pH and it seems to be doing the trick. pH is 8.3 now with the lights on but drops down to 7.9 at night. Ca is 440ppm, magnesium is low at 1000ppm. Alk was 3.5 meq/l. So I have a bucket of magnesium something er other here from BRS, so I'll use one of the reef calculators and see how much I need to add.