Reactors, Kalk Dosers, and Calcium, Oh My!

[sunni]

I keep reading about kalk dosers, kalk reactors, and calcium reactors... I am very confused!

What is the difference between kalk and calcium? What is the difference between the reactors and the dosers? Kalk reactor vs. Calcium reactor?

How do you know what you need and when?

[Warnberg]

All of the mentioned are used to maintain calcium and alkalinity levels in the tank just differant methods of doing it. Kalk or Kalwrasser or Limewater are all the same, they are usually dripped (doser) or used to replenish evap water.

A reactor is something where a chemical change actually occures (calcium reactor) this device uses a media and CO2 to react with the media to produce calcium and this is feed to the tank, it also uses the existing tank water to circulate thru the reactor (no additional water added).

There are several sites that can explain it better than I have here, but hopefully you get the idea.

[MCary]

I can expand a little on the equipment. Then I suggest you go to the Chemistry forum and ask Randy to direct you to some of the articles he's written on Calcium, Alkalinity, and pluses and minuses of dosing systems.

Kalkwasser dosing was developed in Germany. Hense the reason the term is in German. I believe the translation is calcium water or lime water. Kalkwasser is like Kool-Aid. At some point when making kool-aid it won't get any sweeter and any extra sugar you ad is going to settle on the bottom. For Kalk at a normal freshwater pH the amount water can hold is about 2 teaspoons/gallon. The rest will settle out. What a kalk reactor will do is stir the kalk at regular intervals to keep the water saturated as it is replaced. So for instance, if you put the reactor in line with your top off system a cup of saturated water pumped out of your reactor into your tank would be replaced by a cup of fresh water from your topoff reservoir. The reactor would then stir it into the rest and resaturate it. This makes it possible to "load" your reactor with alot of kalk so you don't have to mix it up fresh daily.

Calcium reactor simplified. Corals use calcium and alkalinity in a high pH environment to build skeletons. If those skeletons are exposed to a low pH they release that calcium and alkalinity. The trick is to take saltwater which is naturally a high pH and lower it so the calcium can be released. This is done with Carbon dioxide. A calcium reactor mixes water it gets from the system with CO2 in a recirculating chamber. The low pH dissolves the crushed coral media in the reactor producing a calciium saturated water which is then dosed into the tank.

The need for either depends on the demands of your tank. Coralline algae and corals, mostly LPS and SPS need calcium and will take it from the water column. If you have little in the way of hard coral a simple 2 part solution can be added at regular intervals or even water changes to maintain calcium levels. As demand rises, these automated systems makes upkeep easier.

Mike

[sunni]

Thanks, I think I understand... a bit. :p

I will read some more.