New rock absorb ALK?

[Waters]

I recently swapped out a couple of pieces of CaribSea Life rock in my 9 month old tank...within 5 days, my ALK has dropped from low 8s to mid 7s. It is held very consistent with a Trident....never moves a whole lot. Nothing else has changed. The trident is dosing a TON more ALK solution trying to keep up. Will the addition of a couple of pieces or rock absorb ALK? I swapped out roughly 1/15th of the display rock.

 

[laverda]

I would not expect that at all. I would double check your Trident. Measure your ALK with a test kit.

 

[Randy Holmes-Farley]

It can initiate some precipitation of calcium carbonate. Not usually a big issue. More of a concern with sand.

 

[Waters]

I would not expect that at all. I would double check your Trident. Measure your ALK with a test kit.

Yeah, that is the first thing I did. Double checked it with a Hanna.

 

[The Opinionated Reefer]

Yes it can, in my original nano tank, I used aquaroche ceramic rock and used coral pro salt. The dkh measured 11 when I set it up and within 6 days it was down to 5.5dkh with nothing but a few softies and one small Duncan in the tank. I dosed it back up and it kept sinking, I dosed it back again and it was up and down like a yoyo. I couldn't for the life of me understand why this was happening then after lots of googling I found threads on another forum where a similar thing was happening with aquaroche ceramic rock. In the end, it took about 3 months before it stopped sucking up alkalinity.

 

[blasterman]

If it was replaced with live rock the alk is likely being consumed by the biology on/in the rock ramping up in the new tank.

The period right after a tank cycles is when alk consumption is screwy and can dive like a shot duck for weeks/months. Basically we have a mini cycle caused by the introduction of new biology.

If it was inert rock I have no idea.

 

[Waters]

If it was replaced with live rock the alk is likely being consumed by the biology on/in the rock ramping up in the new tank.

The period right after a tank cycles is when alk consumption is screwy and can dive like a shot duck for weeks/months. Basically we have a mini cycle caused by the introduction of new biology.

If it was inert rock I have no idea.

Well...it is kind of in-between. It is CaribSea life rock which is dry rock seeded with bacteria. I did have the same issue when I first set up the tank....I could not keep ALK elevated regardless of how much I was dosing. I am now having the same issue even though I only replaced a couple of relatively small rocks. My ALK dosing has increased by almost 50% and my ALK just keeps dropping, now down to 7.54 when is was stable around 8.