Any reason why my tank stopped using Alk???

Cment · Nov 27, 2016

So this tank has been running for 6 months I have a good amount of corals in the tank (LPS,SPS,zoas). Alk was steady at 8.6dKH then over a week it jumped up to 11.5. I turned of my Alk pump and let the Alk dropped to 9.6 where it has held for the last 5 days. Ca is still being consumed and is holding steady at 450 and the same for Mg it's holding at 1350. Any reason why my tank would have steady consumption of Alk then all of sudden stop using it? I've never experienced this in the 10+ years in this hobby...

Brew12 · Nov 27, 2016

What are you pH and Phosphates doing?

Cment · Nov 27, 2016

pH steady at 8.2 from Apex
PO4- .02 from salifert
NO3- 3 from salifert

Brew12 · Nov 27, 2016

Cment said:
pH steady at 8.2 from Apex
PO4- .02 from salifert
NO3- 3 from salifert

Corals need to use calcium and alk in equal parts. They can't just stop using alk if they are still using calc. There are some complex (to me anyway) balances that can make it look like one or the other is being used at a higher rate.

There can be other sources of alk that occur other than our normal additions. Such as dosing vinegar or having algae die off. Any chance you have noticed something along these lines?

Cment · Nov 27, 2016

there have not been any changes to the tank other than the Alk not being consumed. I do not dose vinegar or vodka and tank does not have a lot of algae and hasn't really since it started.

Brew12 · Nov 27, 2016

I'm also guessing you didn't do anything to try and buffer your pH... that would be too obvious. I'm at a bit of a loss, so lets see if we can get some more help.

#reefsquad

Cment · Nov 27, 2016

That's correct I have not try to buffer my pH in any way...lol I'm with you, I have no idea why this could be.

Sabellafella · Nov 27, 2016

Cment said:
So this tank has been running for 6 months I have a good amount of corals in the tank (LPS,SPS,zoas). Alk was steady at 8.6dKH then over a week it jumped up to 11.5. I turned of my Alk pump and let the Alk dropped to 9.6 where it has held for the last 5 days. Ca is still being consumed and is holding steady at 450 and the same for Mg it's holding at 1350. Any reason why my tank would have steady consumption of Alk then all of sudden stop using it? I've never experienced this in the 10+ years in this hobby...

Have you added new corals? Or tinkered with your tank at all right before the consumption stopped? Have you checker your pumps calibration?

Cment · Nov 28, 2016

Sabellafella said:
Have you added new corals? Or tinkered with your tank at all right before the consumption stopped? Have you checker your pumps calibration?

good questions...I have not added any new corals or tinkered with the tank, its just kinda been on autopilot for the last 3 months. The pump was new from BRS and I measured its calibration before using it. Its suppose to be a 1.1 ml/min but mine is actually 1.3 which I adjusted my dosing accordingly to but the pump has been offline now for almost a week with absolutely no alk consumption and I have not done my weekly water change either....

kendavjac · Nov 28, 2016

Have you tested with another test kit to make sure yours is still giving good readings?

jenreefer · Nov 28, 2016

kendavjac said:
Have you tested with another test kit to make sure yours is still giving good readings?

+1 I would worry more that test kit was expired and reading was not accurate. Try with a new kit to verify result.

Cment · Nov 28, 2016

jenreefer said:
+1 I would worry more that test kit was expired and reading was not accurate. Try with a new kit to verify result.

Not the test kit, I actually purchased a new one since I thought it maybe the cause. This is a brand new salifert box expires 10/19. I also verified with my lfs of my current reading yesterday...

Todd31 · Nov 28, 2016

I had that happen once, and eventually figured out that my doser wasnt dosing accurately. I'd double check that to rule it out....

jenreefer · Nov 28, 2016

Cment said:
Not the test kit, I actually purchased a new one since I thought it maybe the cause. This is a brand new salifert box expires 10/19. I also verified with my lfs of my current reading yesterday...

well, that is peculiar. will be following in hopes of learning the cause. this is a new one on me.

@Randy Holmes-Farley help please

“When you eliminate the impossible, whatever remains, however improbable, must be the truth.”

Todd31 · Nov 28, 2016

ooops sorry you mentioned in one post that you tested the doser....

Cment · Nov 28, 2016

Todd31 said:
I had that happen once, and eventually figured out that my doser wasnt dosing accurately. I'd double check that to rule it out....

I will do this. However the doser has been off line for almost a week and the tanks Alk has not moved from 9.6. I am still currently dosing Ca since that is being consumed. The tank is full of SPS that appear healthy along with healthy LPS and zoas.

Cment · Nov 28, 2016

Todd31 said:
ooops sorry you mentioned in one post that you tested the doser....

No worries!

Cment · Nov 28, 2016

jenreefer said:
well, that is peculiar. will be following in hopes of learning the cause. this is a new one on me.

@Randy Holmes-Farley help please

“When you eliminate the impossible, whatever remains, however improbable, must be the truth.”

lol I know! I'm really scratching my head on this one. I'm OCD when it comes to keeping parameters stable especially Alk since I have some nicer acros...

Brew12 · Nov 28, 2016

Cment said:
I will do this. However the doser has been off line for almost a week and the tanks Alk has not moved from 9.6. I am still currently dosing Ca since that is being consumed. The tank is full of SPS that appear healthy along with healthy LPS and zoas.

I'm still scratching my head on this one. I still do think it is important to keep in mind that corals cannot use Ca without also using Alk. I think that leaves 3 options.
1) Ca is being consumed by some reaction other than use by coral.
2) Something is leaching carbonate into the tank.
3) There is an anomaly in your water causing inaccurate test results on your Alk.

I'm thinking it is either 2 or 3, but have no idea what would have changed to cause this.

Randy Holmes-Farley · Nov 28, 2016

Cment said:
So this tank has been running for 6 months I have a good amount of corals in the tank (LPS,SPS,zoas). Alk was steady at 8.6dKH then over a week it jumped up to 11.5. I turned of my Alk pump and let the Alk dropped to 9.6 where it has held for the last 5 days. Ca is still being consumed and is holding steady at 450 and the same for Mg it's holding at 1350. Any reason why my tank would have steady consumption of Alk then all of sudden stop using it? I've never experienced this in the 10+ years in this hobby...

If it isn't using alk, it isn't using calcium. There's no other mechanism for calcium consumption.

It might be test error, dosing error, or actual consumption decline. Artificial rock can add alkalinity.

In any case, dosing less or none till it drops seems appropriate.