KORALlith Calcium Reactor Media
Picture from January 2000

I used KNOP KORALlith brand medium for my calcium reactor mainly because it was part of a package deal with the reactor. :c)

The medium used in the calcium reactor is very important. It's quality determines the degree of success in using a calcium reactor. Two important things to consider about the medium are: 1) chemical composition and 2) particle size of the media.

The chemical composition of the medium is important since it will be dissolved in the reactor and whatever the medium is composed of will then be added to the system. Phosphate is the main one to worry about. It's also possible that Magnesium and Strontium will be included.

KORALlith claims to be 99.5% aragonite and have untraceable phosphate.

The particle size of the medium has a direct effect on surface area available in the reactor. The larger the size the less surface area available and the slower it will dissolve. Smaller particles have much greater surface area and thus dissolve at a faster rate. This tends to be what one looks for in a calcium reactor medium. However, you have to keep an eye out that the medium doesn't turn to a fine powder mush. This light powder like substance can then be dumped into the tank and make the tank cloudy.

One thing to note is that this is a very dusty product and required significant time and water to clean the media. I don't know how critical it is to clean the media before using it. The K2R instruction manual said to rinse the media well. However, I know of other reef hobbyist who did not rinse it and reported no problems.