Alk and CA invrease by itself ?!?!

[SCiMMiA]

Hi !

A couple days ago I noticed my Alk and Calcium stopped droping everyday (consumption).
So I stopped dosing.
I dose redsea kh and ca manually everyday.
I test almost everyday. My test always seems to be right on.

Now, a couple days ago, my pH started to drop way lower then what my tank is normally at !
My pH is always between 8.2 to 8.5. But it droped to around 7.7 and never reach 8.0

One thing has changed at the same time the pH droped. We started the A/C so the windows are now never open.

I know that a build-up of Co2 in the house can cause my pH to drop. I don't have a problem with this since I am not chasing pH numbers anyway.

BUT, what I can not understand is WHY my alk and ca increase everyday ?!?!? 3 days ago when i stoped dosing my alk was at 8.4 and now it reached 9.35 without anything added to the tank !?!?!?

Is there a relationship of something that i don't understand ?
My Mg is constant at 1400, it never drop.

If you have an idea. Let me know.
Btw all corals are growing and happy so I am not too worried but I would like to understand what is happening!

 

[lapin]

I would not expect that much of an increase because of co2 but it might be possible. A calcium reactor works by adding co2. lowering the ph disolves the media thus increasing the alk and calcium. Perhaps with the lower ph your corals are not taking up as much alk as well.
Just something to think about.

 

[SCiMMiA]

Then, can the pH be so low ( 7.7 ) that it disolve my aragonite sand wich increase ca and alk and NOT Mg ?

If that is the case, i hope my sps won't disolve also !

 

[SCiMMiA]

Jsut an update, I opened all the windows in the house today since it was not hot outside and PH increased to 8.2

So I'm 100% sure it is a Co2 issue....

Alk is steady at 9.35.

Tomorrow, we will let the windows open (not really,my air exchanger will be on)
I guess my pH will stay above 8.0 but I'll report if the Alk/Ca resume consumption...

 

[bertoni]

Aragonite won't dissolve in our tanks. If it did, it'd add calcium and alkalinity at the ratio of 2.8 dKH per 20 ppm calcium. For calcium and alkalinity to rise, something must be added to the water column. Some of the more common stealth sources would be tap water and artificial live rock.

 

[SCiMMiA]

After 24 hours with pH back to normal (8.28), The Alk started to drop again like it used to.

From 9.35 dKh to 9.0 dKh

When it reach 8.4 I'll resume dosing my 2ml per day of RedSea Foundation B (Liquid)


There must be a relationship somewhere with the pH drop and the Alk/Ca that went up.

I'll keep this post updated. We will resume the A/C next week when the temperature will be hot again.

Maybe I will never know why Alk/Ca increase when pH drop, but at least I will data to show it next week if the tank react the same way.

 

[SCiMMiA]

Update:

Since June 6:
my pH was stabilized at my normal 8.2-8.3 range.
my Alk resumed the normal 2ml / day dosing consumption.

So since June 6, everything is back to normal.

On June 12 , we started the A/C again and closed all the windows.

Now today, on June 13, my pH droped again to 8.1 and my Alk did not drop like normal, in fact it increased AGAIN, from the normal 8.4 dKh it is at 8.7 dKh !


Sooooooo...... ! It can not be a coincidence !
There is really something about pH - Co2 - Alk that is related !

More Co2 = pH decrease, that, I understand.

What is up with pH decrease and Alk increase ?!?!
Or does more Co2 = more Alk ?!?

I did not test calcium but I bet it also increased since it did last time....

--------- Thesis...

Is there a relationship that Co2 increase the carbonate something in the water ??
Or does our Alk and CA test report wrong numbers because of Co2 ??


hmmm, while I write this, I have an idea. I will take a water sample, shake it outside to remove the Co2.
If I test this water and Alk is still up = Alk DID really increase and the test is reporting the right values.
If I test this water and Alk went back down = Our test kit are affected by the Co2 in the water.


I'll report back with what I find.

 

[SCiMMiA]

ok, I shaked the hell out of my water sample outside for an hour.

The Alk still test at 8.7 dKh


sooooooo There is no doubt that , if what drop my pH is Co2, the test kit does report the right value Co2 or not.

There is only 2 conclusion to this but i'm not sure which one to pick.

1- The "Co2" increase droped the pH which in turn made something happen in the tank. What? I don't know. Coral release Alk and CA ? , Sand release Alk and CA, what else ?

2- The drop in pH is not caused by Co2, but something else that can affect the Alk/CA reading on test kit OR something that really make the Alk and CA go up.... ?



Anyone think my conclusion is wrong ? Or do you have an other idea ?
What else can it be ?

 

[SCiMMiA]

Just to clarify, I said my pH droped to 8.1 but that was at the "normal" time I test (7pm). Just before Lights on it droped to 7.96

 

[bertoni]

The only way that alkalinity can increase is if something is added to the water column. Carbon dioxide won't do that. Some of the more common stealth sources of alkalinity include tap water, artificial live rock, and pH buffers. All pH buffers add alkalinity, despite any advertising.

 

[SCiMMiA]

To wrap-up this thread, I now know that what was happening is when your pH drop, it makes the sand and/or the rocks disolve and that is what makes Ca and Alk increase !