Alk drop carbon dosing?

[lapin]

My tank has been up for 18 months. Alk 8.7 to 9 600 gallon system
10% water change per week, salt mixed to 9 dkh, Cal reactor same drip rate and cal reactor ph.
My alk has been stable for months. Tank Ph 8.3 to 8.4
I added 1 wall hammer about a week ago.
This week, before I did a water change, I measured my alk as always. It was 7.7. Tested 3 times cause I have an old brain and eyes. I also tested the hanna with stds. Alk has never dropped like this before.
Now to add 1 more thing into the mix. I started carbon dosing about 2 months ago. NPS so over feeding caused an increase in Po4 and N. I have it back down to 8=N and .05=P. I dose 30 ml vinegar and 4 ml vodka per day. Not much but it does the trick.
Since I was a bit low on iodine. Never had it tested until 2 months ago (ICP test) I dosed Vibrant liodine (10ml) 2 weeks ago 1 time. Not much for 600 gallons.
Could the wall hammer, carbon dosing or liodine cause a 1 dkh drop over a weeks time?

 

[Ben little79]

What is your magnesium level.. And calcium level..

 

[lapin]

cal=435 mag=1485
same as it ever was

 

[Ben little79]

So only your alk depleted.. Its not precipitation then it seems.. Must be the wall hammer i would assume..

 

[lapin]

So only your alk depleted.. Its not precipitation then it seems.. Must be the wall hammer i would assume..

I dont know the true cause.
To me, with 600 gallons, 1 wall hammer should not be able to take Alk down 1 dkh in a week. But who knows

 

[MnFish1]

Did you verify the alk with a couple different tests (i.e. not repeating the same test 3 times)? According to this thread https://www.reef2reef.com/threads/carbon-dosing-reduces-alk.301543/
carbon dosing should not reduce alkalinity

 

[lapin]

I tested my water change water as I was mixing it. It was 8.8 then with a bit more salt it went to 9.0 I tested the tank 3 different times over 1 hour while mixing water. It was the same (7.7) all 3 times. I added 200ml of Randy Baked Baking Soda water and brought Alk up a bit in the tank. I did a water change and the tank came up to 8.4. I will dose some of Randys water especial tomorrow and test again. Do an extra water change and get it back to 9. If it drops every day my next step is to increase my bubble count and lower the Ph in reactor.
Its just weird it dropped like that out of the clear blue sky for no reason I can figure.

 

[Ben little79]

This baked baking soda.. Is it added to ato resivor?..

 

[Ben little79]

I also suffer from alk drops..

 

[lapin]

This baked baking soda.. Is it added to ato resivor?..

I add the mixture to the high flow area in my sump where the water exits the tank and overflows into the socks. I think this way, if any precipitation occurs, it will go into the socks and the water will dissolve it again.
http://www.reefkeeping.com/issues/2006-02/rhf/index.php

 

[Ben little79]

That was a wonderful article.. Extremly insightful.. Thank you

 

[lapin]

Wanted to update this.
Something has to be growing faster. Maybe coralline. My alk consumption has gone up 0.2 dkh per day.

 

[Randy Holmes-Farley Verified Community Expert]

So only your alk depleted.. Its not precipitation then it seems.. Must be the wall hammer i would assume..

Not necessarily true. The small calcium drop that accompanies a small alk drop will get list in the testing noise. The magnesium drop will be near impossible to detect even with a high end lab instrument.

 

[Randy Holmes-Farley Verified Community Expert]

Faster growth makes sense. Carbon dosing might even promote it by feeding the corals directly or indirectly via bacteria.

 

[Ben little79]

Hello .. Thankyou for for all the great articles.. I read through them often.. Where would i find some on bio pellet reactors..

 

[Randy Holmes-Farley Verified Community Expert]

I’ve not written one specifically in biopellets, and don’t have a link to one from someone else, but I discuss them along with other nitrate control methods in the nitrate article in the article sticky.

 

[BeejReef]

Did you ever get to the bottom of this?
Was wondering if it was possible that the carbon dosing enabled some naturally anaerobic areas of your tank to begin denitrification. I've read that anaerobic denitrification does consume alk and the timeframe you gave as "a few months" after initiating carbon dosing would fit with an area getting established.

 

[lapin]

Did you ever get to the bottom of this?
Was wondering if it was possible that the carbon dosing enabled some naturally anaerobic areas of your tank to begin denitrification. I've read that anaerobic denitrification does consume alk and the timeframe you gave as "a few months" after initiating carbon dosing would fit with an area getting established.

I dont really know what it was. It has now slowed to the about the same alk consumption level it was before.
My best guess is something took off, perhaps spurred on by the carbon dosing, and was consuming alk.
For now its another reefing mystery.

 

[Randy Holmes-Farley Verified Community Expert]

Did you ever get to the bottom of this?
Was wondering if it was possible that the carbon dosing enabled some naturally anaerobic areas of your tank to begin denitrification. I've read that anaerobic denitrification does consume alk and the timeframe you gave as "a few months" after initiating carbon dosing would fit with an area getting established.

Nitrate consumption by anoxic denitrification with organic carbon doesn’t consume alkalinity.

 

[Randy Holmes-Farley Verified Community Expert]

Section 4 in the article of mine below shows the balanced chemical equation, producing alkalinity (the exact amount that was list when the nitrate was formed from ammonia)

Nitrate in the Reef Aquarium - REEFEDITION

Nitrate is an ion that has long dogged aquarists. It is typically formed in aquaria through the digestion of foods, and in many aquaria it builds up and can be difficult to keep at natural levels. In the past, many aquarists performed water changes with nitrate reduction as one of the primary...

www.reefedition.com