Understanding Kalk at night alk swings

[SMG91]

So I began dosing kalk at night a couple of weeks ago to counteract the diurnal swing of my pH on my 60gal system. According to hamza's calculator I am only adding .05dkh of alk from midnight to 9am, yet I see on average an alk swing of .5-.6dkh between those hours with the pH only dropping .15, is there an explanation for where the extra alk could be coming from? The tank is in a closed off room currently with the only window in the room open to help with co2.

I have confirmed the trident with Red Sea kh kit and have recalibrated the trident and ph probe recently, but am still getting the same results.

 

[Randy Holmes-Farley Verified Community Expert]

Which is alk and which is pH?

Ho much kalkwasser did you dose?

 

[SMG91]

Which is alk and which is pH?

Ho much kalkwasser did you dose?

Alk is the orange (scale on the left), blue is my pH (scale on the right) Total of 2130ml of full concentrated kalk through my kalk stirrer between midnight and 9am.

 

[SMG91]

I must have entered my data into the calculator incorrectly. I just entered everything into the calculator again and 2130ml of saturated kalk will raise the alk in my system by 1.16dkh.

 

[Randy Holmes-Farley Verified Community Expert]

OK, that all makes sense then.