Increase PH but not ALK

[cykso]

Hi,

Is it any way that I can increase my tank's ph but not alk?
I found out that most of the over the counter products that claim will raise ph also will increase ALK as well.

ALK: 200 ppm
CA: 405 ppm
PH: 7.83

Thanks

 

[Randy Holmes-Farley]

The only way to increase pH and have no alkalinity increase at all is to drive out CO2, either by more aeration with fresh air, or a lot more photosynthesis.

Usually, however, adding limewater is a good way to go. While it does supplement alkalinity, it also adds calcium so alk does not rise relative to calcium. Also, the demand for alkalinity and calcium rise as the pH rises, so usually the alkalinity does not rise appreciably and the pH rises substantially when adding limewater in a situation such as yours.

This article has more:

Low pH: Causes and Cures
http://reefkeeping.com/issues/2004-09/rhf/index.htm

 

[rrome]

From an hypotetical point of view, would addition of KOH or NaOH accomplish this (probably temporarily)?

 

[Randy Holmes-Farley]

Nope. Those are alkalinity supplements, just as is limewater (calcium hydroxide in water).

 

[cykso]

Thanks for your reply. So if I decide to use kalkwasser, is this the one I should use? http://www.kentmarine.com/saltwater/kw.html

 

[Randy Holmes-Farley]

That is a fine way to go, yes. Just be sure to dissolve it in water and add it slowly (such as dripping or very slow pump). This article has more on how to use it:

What Your Grandmother Never Told You About Lime
http://reefkeeping.com/issues/2005-01/rhf/index.htm

 

[cykso]

I read an article saying that we can add vinegar into kalkwasser in order to provide enough CO2. What is your opinion about this?
http://www.reefscapes.net/articles/breefcase/kalkwasser.html

 

[TwistedTiger]

<a href=showthread.php?s=&postid=7074792#post7074792 target=_blank>Originally posted</a> by cykso
I read an article saying that we can add vinegar into kalkwasser in order to provide enough CO2. What is your opinion about this?
http://www.reefscapes.net/articles/breefcase/kalkwasser.html

Vinegar will lower the PH, you are trying to get rid of the CO2 to raise your PH so adding more would not help you.

 

[Randy Holmes-Farley]

I agree. Vinegar allows a bit more lime to dissolve into the limewater, drives bacterial growth in teh aquarium, reduces the pH, and consumes some O2.

 

[cykso]

Thank you guys!

 

[Randy Holmes-Farley]

:thumbsup:

Happy reefing.

 

[cykso]

An update. I managed to aerate my water a bit since last week. The ph starts going up and now my ph is around 8.0 (Haven't start dose Kalkwasser yet). Yeah!!

 

[Randy Holmes-Farley]

So far so good.

Good luck.