understanding DIY Kalk Dripper

[Mr..Tang]

I read the DIY in the dripper unit. Had a few questions that I have had for some reason an hard time getting answers.
First, when you add the kalk, do you use your total gallons of your system to determine the amount of kalk? For example, If you had 100 gallons,, would you add 100 teaspoons of kalk to the dripper? Than once you figure that out, how do you use the air line valve to adjust your flow?

Any help would be greatful!!!

Mike:bum:

[bertoni]

You can dose 1 tsp per gallon of water in the dripper unit, as a starting point. The limit (without adding vinegar) is 2 tsp per gallon of RO-DI water. That's a saturated solution. This article might help:

http://www.reefkeeping.com/issues/2005-01/rhf/index.php

[Mr..Tang]

So How do you determine how many tsp you need? Is it the total volume of aquarium or your dripper bottle?

[baj]

I think your confusion about dosing limewater to maintain a Ca and Alk balance is probably due to treating limewater as a 2-part additive. Saturated limewater (either Lime or Quicklime dissolved in water) can deliver a finite amount of Ca and Alk, you cannot add more Ca and Alk by adding more calcium hydroxide into water, the lime will just precipitate out. Adding limewater will also raise the pH significantly. To answer your question briefly:

1) The number of teaspoons of lime is not determined by your tank volume, it is determined by the limits at which it reaches saturation, which is 2tsp/gallon as Jonathan Bertoni described above.
2) You will need to determine the Ca and Alk demand of your system, and note that:
3) Saturated limewater contains about 808 ppm of calcium and 40.8 meq/l of alkalinity.
4) For simplicity lets consider the Ca to be 800ppm and Alk to be 40meq/l, note that the ratio is 20:1 which should also be the ratio of Ca/Alk depletion in your tank due to the formation of CaCO3
5) For a 100g tank which has Ca at 400ppm, lets say you add 0.25g (or a quarter of a gallon) of saturated limewater which has Ca at about 800ppm. Converting everything to the proper units, we have 100g ~= 380L in which Ca is present as 400mg/L. Into this you are adding 1L of saturated limewater, therefore raising the Ca concentration by 800/380 = 2.1mg/L or 2.1ppm.
6) In terms of gallons, we see that in a 100g tank, adding 1g of saturated limewater raises Ca by about 8ppm. Using the 20:1 ratio, we find that Alk concomitantly rises by 0.4meq/l
7) Therefore, if the evaporation rate of the above tank is 1g/day and the Ca demand is more than 8ppm/day, then using saturated limewater alone will not keep up with the demand, when kalkwasser or limewater is used as a top off.

There are caveats to this and I may be wrong in my assumptions/calculations. I would suggest reading the articles here:

http://www.reefcentral.com/forums/showthread.php?s=&threadid=102605