Kalk and pH

[ccny]

Hey guys, I'm thinking of using kalk and vinegar for a top of drip. Has anyone ever tried to measure the pH of the solution? Is it possible to add just the right amount of kalk to vinegar so it could get a pH of 8.2?

 

[tangir1]

Take a look at Randy's article in Advanced Aquarist. or Craig Bingman's article on the use of vinegar with kalk.

 

[ccny]

uh...thanks...

I've read some of these articles and I don't know if this comes from one of the ones you are referring to but:

Quote:
"By the way, the "stoichiometric" amount of Vinegar, i.e., that amount that provides the exact equivalent of enough CO2 to react all the Kalk powder to Calcium and Bicarbonate, turns out to be about 25ml of 5% Acetic Acid per liter of saturated (0.02 moles/liter or 1.5 grams/liter) aqueous Calcium Hydroxide solution (Kalkwasser). I've used 30ml of Vinegar to a ½ teaspoon of Ca(OH)2 per liter of mix without any problem, but recommend about 15ml to those new to using Vinegar."


Even with all that fancy stoichiometry talk, he still makes a guesstimate of 1/2 tsp per 30cc of vinegar.

The question still remains:

Has anyone actually tested the pH of this solution to see if it matches tank water?

I'm no chemist but adding 15cc of vinegar to one liter of water with just 1/2 tsp of kalk sounds like it's going to be acidic. Just wondering if anyone's actually checked this out.

Thanks

 

[Len]

I don't believe vinegar would neutralize the very high pH of kalk. I admittedly haven't tried.

This is a good read:
http://www.advancedaquarist.com/issues/feb2003/chem.htm

Unfortunately, animalnetwork's Aquarium Frontier articles (like the one Craig wrote about Kalk and vinegar) are currently offline. I hope they get it running again soon.

Here's another article written by a member of Reefs.org:
http://www.reefscapes.net/articles/bree ... asser.html

Hope that helps.

 

[Len]

Man, i just spent the last 10 minutes searching the web for the pH of kalk+vinegar. I sympathize with you now, ccny

 

[ccny]

Thanks Len.

I'd imagine it is entirely possible to neutralize kalk. As an extreme example, adding a pinch of kalk to a gallon container of vinegar will still leave you with acid vinegar. If you couldn't neutralize it, it would forever accept protons, etc. the more kalk one would use over time.

I'll try this out myself and see what turns up since it looks like no one else has. I think the vinegar thing is a good idea so it is not so caustic to handle and less caustic to the tank.

It's really the last article that caused me the angst the ask the question.
http://www.reefscapes.net/articles/breefcase/kalkwasser.html

Just seems like adding that much vinegar to that little kalk will lead to an acidic solution.

Thank again.

apologies for the lack of html skill

 

[Len]

Please let me know what you find. I'm really curious now that I looked for a while. I'm sure you could neutralize the base or even make the solution acidic with enough vinegar, but probably not amounts you'd want to add without negative consequences to the solution. But I've always hated chemistry, so I'm not the one to ask