Oh rapidly dropping

[Brooks Allman]

I added kalkwasser to my ato last night to stabilize alk and bring my ph up a bit. It leveled my ph at 7.9 all night but this morning it dropped from 7.9 to 7.8 in an hour. I’ve never seen a drop like this before. Any ideas or suggestions?

 

[afartindolphin]

Not really that big of a drop, my daily swing is sometimes 7.85 to 8.35. Guessing you have constant pH monitoring? Post the graph for the last week. With Kalk in an ATO you'll only get the boosts whenever your topoff runs, and that will fluctuate depending on evaporation.