pH question for ya

[mini-reefer]

I recently got a digital pH tester so I've been testing the water at different times of the day. With lights and without lights.
Last night I dripped kalkwasser for top off. Roughly 2 liters worth with a drip per second. The water is RO/DI. I just tested the tanks water out of curiosity sake and the pH is at 8.6. Thats high in comparison to the normal 8.2-8.3 range I have been getting day or night.
So have I "overdosed" the tank or is this a typical reading after dosing? I stopped it after taking the reading and will watch it before and after the lights start to come on just to see where it goes. Anyone with similiar results?
Mini-Reefer

 

[10k]

You may have "overdone it" a little bit. Not to worry though. Properly mixed Kalk has a PH around 12.0, and will spike the PH in your tank if it is added too fast. Try dripping at a lower rate, and more often, to maintain Calcium levels. Better to dose slowly, all of the time, than to put in too much once or twice a week. I drip my Kalk constantly (slowly), and don't have a problem with PH spikes. My PH is a little higher than I would like, but hopefully my reactor will be finished soon, and this will be repaired..