Why Did Alkalinity Tank?

[DiZASTiX]

An inquiry for you, my friend:

1. Can you guess what the reason for this alkalinity drop is?
2. Will the drop require correction (I am happy with the new range, but I am worried about the speed of the drop). Or perhaps I asked this question too late. Corals look happy.
3. Do you anticipate continued drops?

Thank you, as always.


Details

Alkalinity suddenly dropped for no apparent reason. There were no deviations in maintenance or dosing to the aquarium, except for Seachem Stability, a "canned bacteria" product. I have dosed this in the past, but have not noticed drops in alkalinity like this. However, they may have existed without my notice:

1 Week Alkalinity​

1 Month Alkalinity​

The alkalinity is seen to suddenly drop 2018.7.15 @ 7:25 am; at this point, there are seeming fluctuations, which I attribute to rounding errors of Hanna, and Hanna's limitations on the number of significant figures. Over the course of around 24 hours, the alkalinity drops from an average of 7.9 dKH to around 7.4-7.5 dKH.

 

[Randy Holmes-Farley Verified Community Expert]

A 0.5 dKH drop per day is small and not unusual. I’m not sure which of the many possible processes is responsible, including coral or coralline algae growth, other creatures calcifying (snails, etc) or abiotic precipitation, etc.

I’d dose it to your target and just keep watching.

 

[DiZASTiX]

Thank you. That's very reassuring.

 

[DiZASTiX]

I guess what surprises me is that I do have dosing pumps to keep alkalinity stable, and yet despite that, it suddenly dropped. A day ago I did add a single coral frag and three peppermint shrimp.

 

[Randy Holmes-Farley Verified Community Expert]

I guess what surprises me is that I do have dosing pumps to keep alkalinity stable, and yet despite that, it suddenly dropped. A day ago I did add a single coral frag and three peppermint shrimp.

I didn’t realize you were dosing already, but that makes an increase in demand even less unusual as things change, grow, etc.

 

[Randy Holmes-Farley Verified Community Expert]

Maybe the dosing pumps are deviating from the initial volume.