Kalkwasser +vinegar?

[Doc Shake]

Ok, who adds vinegar to kalk and why? What is the result?

 

Ca(OH)2+C2H4O2+H2O---->???? Help me out here.

[Whitten]

When I add it helps to keep the mixture from precipitating out of solution. Apparently it will keep you from making calcium carbonate when you add the mixture to water. That is what I have heard, and when I did drip the mixture I was able to cover the bare back wall of my Nano cube with huge splotches of coraline.

Whether or not it really works like I have read is still a mystery for me, but all the results point in the direction that it is effective and most deffinately keeps the kalk from precipitating out.

[footbag]

Adding vinegar allows you to increase the amount of Kalk you add to the water. Normally, CaCO precips out of water at 2 tsp /g. With vinegar you can increase that to 4 tsp/g (Not sure about this number).

[Whitten]

Sounds better than what I wrote.

[onthefly]

Nothing new to add, just a bit more techy:

 

The vinegar isn't a reactant or a product......it controls the reaction environment by (as everyone has said) reducing the pH.

Therefore, you reduce the solubility constant of Ca(OH)2 and the water become supersaturated with Calcium. Otherwise, CaCO3 is formed and ppt's out of solution.

[BizWizKid]

So, I've come up with a question. I've heard of adding vinegar to kalk before but paid it no mind because I was not dripping kalk yet, but since I am now going to start after stabalizing my tank. I would like to know how much vinegar needs to be added to get the 4tsp/gal ratio for kalk and if the vinegar is added first before the kalk, the kalk is mixed using 1-2tsp/gal then add vinegar to allow more kalk to be added?

[onthefly]

Well, I'm not sure about the 4tsp/gal stuff.....I mix 1cup vinegar and 7.5 tsp kalk in a 3ga glass carboy....mix it around for a few minutes, then add half the water....mix some more...then add the remaining water.....mix some more. After it settles, I hook it up to my tank.

 

That keeps my pH steady at 8.1 over the course of about 3 weeks. Before using vinegar, I once had it hit 9.0 before I caught it.

 

Watch your alk though.....it can drop because of the vinegar. Just be ready with some buffer.

[jimbro]

i add two teaspoons kalk to 40 ml of vinegar, this way im sure all the vinegar gets "used up" by the kalk. i mix the vinegar and kalk first, then pour the sol'n into a gallon jug and let sit. next day i drip it. hope this helps

[Doc Shake]

Thanks for the info, all.

[Dr. Saltwater]

Dose what you add ... that's one thing you should take care of.

 

Calciumhydroxid [Ca(OH)2] also reacts on Co2 ... if I'm wright ... let me think:

 

When Calcium Hydroxid mixes with (RO)-water you'll get:

 

Ca(OH)2 [calcium hydroxid] + H2O [water] -> (Ca++) [calcium ions]+ 2OH- [hydroxid ions] + H2O

 

If there's Co2 present in the water:

 

(Ca++) + (2OH-) + CO2 -> (Ca++) + (CO3--) [carbate ions]+ H2O

 

The next reaction with the released calcium-ions:

 

(Ca++) + (CO3--) -> CaCO3 [calcium carbate]

 

Make sure that the quantity of the Co2 isn't to low or else you'll get a big quantity useless Calcium Carbate. If the quantity of the Co2 is to big in the water the present Calcium Carbonate will mix with the added Carbon Dioxide what makes the water clear of Calcium-ions and Bicarbonate-ions.

This reaction releases Calcium witch doesn't raise the pH by the lose of OH-ions in the Bicarbonate. The Kalk won't be higher nor lower so stays the same.

 

Ok ... I'm losing it now ... I don't use vinnegar but I'm trying to learn the balling-method, I'll post info if you want zzz ???

 

[onthefly]

Wow...you lost me there!

 

In the ideal container (air tight)....you dissolve Calcium hydroxide into water yielding free Ca++ and 2 OH-. With a saturated solution, the water holds as much free Ca++ and OH- as possible, the rest of the kalk sits at the bottom as Calcium hydroxide. With vinegar present, you increase the amount of free Ca++ that the water can hold. However, H+ from the acid react with the OH- and create water. Therefore, by using vinegar, you're losing some of the alk bennies of kalk. The Acetate ion is simply used as a carbon source by corals, bacteria, and algae.

 

Now if CO2 is present....some of the Ca++ get sequestered as CaCO3 solid.....and is no longer soluble under tank conditions. The more CO2 present, the more Calcium you lose.

 

Basically, whether you use vinegar or not....you want an air tight container to keep the amount of CO2 as low as possible.

[Dr. Saltwater]

Yes that's so true

[DarkXerox]

Wouldnt it be useful to boil the water first in order to get out the CO2 dissolved gasses? This is what we do in chem lab for acid base titrations. I think that would get rid of the CO2 buffer, and would keep the carbonate from getting created. This way you would not lose the kH boosting effects of the kalk.

 

Not sure if this would work, but it might be worth a try.

[Dr. Saltwater]

This won't work. If you boil water the alk will drop and so will your Calcium and eventually the kH. The boiling point makes sure that all 'hard' minerals in the water are broken off.

Just use RO water in an air tight container and mix it with the supplements above.