calc vs. kalk at similar ph

[unsped]

the main downside to adding vinegar is lower ph + organics im guessing. im wondering what the amount of CA is coming out of the effluent of a ca reactor vs. the amount of CA coming out of Kalk treated with an amount of vinegar to get it to similar ph (6.5 or whatever)

would treating RO by bubbling or dry ice before mixing kalk help dissolve calcium hydroxide? without the organic effects?

[Randy Holmes-Farley]

The pH of saturated limewtaer with or without vinegar (when not overdosed) is still 12+. Adding CO2 does not benefit and actually hurts limewtaer as it causes precipitation of callcium carbonate.

If you use 45 ml of vinegar per freshwater gallon, you can get roughly 36% more solid lime to dissolve (almost 3 teaspoons per gallon), so the calcium concentration probably jumps about 300 ppm.

From this article:

Expanding the Limits of Limewater: Adding Organic Carbon Sources (vinegar)
http://web.archive.org/web/20030418110415/http://www.animalnetwork.com/fish2/aqfm/1999/oct/bio/default.asp

"Table I gives the vital statistics for the three carbon sources under discussion. As you can see, complete oxidation of about 12 milliliters of vinegar per liter of limewater would provide enough carbon dioxide to balance the inorganic carbon removed from the aquarium when the calcium and alkalinity in a liter of saturated limewater is converted into calcium carbonate. Again, this is the maximum concentration of acetic acid that one would add, and, in practice, I would suggest adding no more than a quarter of this quantity to see how your system tolerates it. The acetic acid would be added at the same time as the lime is added to the water, and it should all be mixed together well. The acetic acid neutralizes some of the calcium hydroxide and forms calcium acetate, or actually largely dissociated calcium ions and acetate ions.

It should be noted that you will be able to dissolve substantially more calcium hydroxide than usual in this way. If you use the maximum concentration of acetic acid listed in Table I, you will be able to get about 36 percent more calcium hydroxide to dissolve than if you mixed it normally. That may be a substantial help to some people in and of itself. Of course, as the calcium concentration goes, up, you would need to add more acetate to get one organic carbon per calcium ion in the mixture. Twelve milliliters of acetic acid per liter of saturated (spiked) limewater will give about 0.73 organic carbon atoms per calcium atom, which will be sufficient to reduce the maximum daily pH the reef attains. (A mixture of acetic acid and calcium hydroxide that has one organic carbon per calcium ion will have a calcium concentration of roughly 0.032 molar, or about 50 percent more concentrated than untreated limewater.)

Even starting at one quarter the maximum dosage, which I’m suggesting you try first, the concentration of calcium in this spiked limewater will be about 9 percent higher than in unspiked limewater. The pH of all of these mixtures will also be somewhat lower than a pure solution of calcium hydroxide in water. And you really should make saturated solutions when you do this, and perhaps check the pH of the solution as well, to make sure it isn’t very low.

There is no reason to use anything other than white vinegar (made for human consumption) for this purpose. You can buy pure acetic acid from chemical supply stores, but a source of “Food Chemical Codex� (FCC) grade acetic acid is as close as your local grocery store. I doubt your corals want cider, balsamic or herb-flavored vinegars either. Just plain old white vinegar should do very nicely and is what I’ve been using. While you are at the store, you might also want to check for pickling lime and stock up: canning season in the northern hemisphere is rapidly coming to a close and pickling lime tends to be seasonally available."

[unsped]

thanks for the info! :)

quick question.... if you feed a kalk reactor with vinegar dosed RO it should have the same effect?

[Randy Holmes-Farley]

Yes, although that may be hard to achieve technically.