Who is dripping kalk and vinegar?

[North Bay 101]

Greetings,
I have been reading about the advantage of adding some vinegar to the kalk drip. Anybody doing this? How do you decide how much vinegar to add? What kind of vinegar to add, distilled or maybe a little bit of red vinegar for flavor?

Thanks for your help

 

[Nathan1]

So, what's the chemical equation for this reaction?

Vinegar: CH3COOH
Water: H2O
Limewater: Ca(OH)2
Carbon Dioxide: CO2

What additional impurities are you adding by using vinegar.

-Nathan

 

[liquid]

North Bay 101,

I'm running kalk/vinegar in my setup right now. You can see the setup that I've constructed to do so at http://liquidreef2.freeservers.com/ in the Equipment section of the website under the Calcium / Alkalinity heading.

If you've read up on kalk / vinegar then I believe you should be familiar w/ Bingman's recommendation for starting out, which is 3 mL vinegar per liter of kalkwasser if memory serves me right. This is where I started out on my vinegar concentration. Start out slowly and monitor your calcium and alkalinity to see where it is. It took me about 2 months to to get it optimized for my situation. Use plain old white distilled vinegar and not anything else as the other vinegars have other impurities in them.

The only time that I recommend kalk/vinegar is when someone has already maxed out their kalk additions and it's started to push their pH over the top...

hth

liquid

 

[Nathan1]

Sarc,

Even simpler than taking your kalkwasser and converting it into calcium chloride then adding NaHCO3:

Buy Calcium chloride salt for melting ice. Buy NaHCO3 as Baking soda.

Sodium bicarbonate medical data sheet info: http://www.jtbaker.com/msds/s2954.htm

Calcium chloride medical data sheet info:
http://www.jtbaker.com/cgi-bin/msds-s.pl?searchdata=1311&int=false

Calcium hydroxide medical data sheet info:
http://www.jtbaker.com/cgi-bin/msds-s.pl?searchdata=1374

Hydrochloric acid medical data sheet info:
http://www.jtbaker.com/cgi-bin/msds-s.pl?searchdata=6900

-Nathan

[ July 25, 2001: Message edited by: Nathan ]

 

[reefworm]

North Bay,
I've been adding white vinegar to my kalk for around 2 years now [I think ... I started when Dr. Bingman's article got posted at Aquarium Frontiers - the article to which Liquid refers]. The primary reason for the vinegar as I recall was to make more carbon ions available which would bond with the calcium in the kalk for calcium bicarbonate. [Sorry Nathan - can't put that into a chemical equation for you

] He recommended the practice especially for smaller tanks whose evaporation rate wouldn't allow for as much kalk addition as larger tanks. I've had good coral and coraline growth, but I made many changes back then, so can't truly assess the impact of the vinegar. Certainly hasn't hurt! Liquid is right on about ramping up slowly. The 3ml per litre sounds right.

regards,
rw

 

[BReefCase]

Nathan -- As unlikely as it may seem, I believe the overall reaction you are looking for is:

CO2(aq) + H2O(l) + CaCO3(s) ==> Ca2+(aq) + 2 HCO3 ¯(aq)

Although it is generally considered insoluble in water, calcium carbonate actually dissolves in even slightly acidic solutions, with the carbonate ion behaving as a Brønsted base.

The "acid" in your tank comes from acetic acid, but is active as dissolved CO2:

CO2(aq) + H2O(l) <==> H2CO3(aq) [i.e., carbonic acid]

If that seems to defy chemical logic, think of it this way, as a three-step process.

CaCO3(s) <==> Ca2+(aq) + CO32¯(aq)

CO2(aq) + H2O(l) <==> H2CO3(aq)

H2CO3(aq) + CO32¯(aq) <==> HCO3¯(aq)

Some of the carbon for the calcium carbonate comes from the acetic acid, too.
As to what additional impurities are added by using vinegar, "white vinegar" is just 5% acetic acid, CH3COOH in water and nothing else. So, hopefully people will be smart enough not to use red wine apple cider vinegar....

[ July 25, 2001: Message edited by: BReefCase ]

 

[Sarc]

I add pool acid (hydrochloric acid) to my kalk. The vinegar maxed out my skimmer!! I balance the addition of chloride ions with the addition of my home-made buffer which adds loads of sodium ions. These should equal out and in the end it would be like i had just added salt to the tank. Simpler way: calcium reactor. Problem? yes, cannot buy them cheap enough in south africa. Too expensive to get from states.

CHris

 

[Mouse]

Fu**in hard core man, you guys rip at chemistry. One day, maybe, if i get a bigger brain.