Live Sand Filters and Changing from Berlin to Live Sand. -------------------------------------------------------------------------------- March 15, 1995 ---------------------- Copyright A. Thiel, 1995 As the use of Live Sand Filters is increasing more and more questions about how to set these systems up are received. I have covered this in several newsletters already in Volume IV. The questions revolve mainly around the kind of materials to be used, the thickness of the layers, whether the void space is necesarry and what it accomplishes. Let me try and deal with these in order. The basic Jaubert set up uses a void space (discussed later) and then a first layer of materials that is made up of crushed coral and crushed shells. The crushed corals is easy to obtain as several companies sell bags of it (there even if an aragonite one on the market which is the one that is recommended over other ones). The shells can often be found as whole shells which you will then have to crush yourself and mix with the coral pieces. The recommendations as to how thick this layer should be vary. My personal experience has been with layers that are 1.5 to 2 inches thick, sit on top of the plenum and is sepearted from it by egg-crate covered with mesh such as the one you can buy for porch door screens. You do not want the fiberglass or metallic one but the plastic. This is a commonly found screening material in hardware stores and holds up well. It also does not let the crushed shells and gravel through. We definitely do not want this to happen as we want to keep the plenum or the void space at the bottom of the set up free of anything except water. On top of the crushed coral/shells a mesh needs to be placed so the live sand can be placed on it. Because the sand is fine the mesh used needs to be very fine too or the sand will slowly migrate through the mesh (which we do not want to happen). The porch door screen mesh is not fine enough for this in most cases. I therefore recommend that you use either very fine mesh nylon or untreated felt (meaning it has not been treated with anti-molding agents and fire retartands). The live sand is then placed on top of it. The layer of live sand should in my experience be between 2 and 4 inches thick and should be laden with live organisms. This is most important for this type of filter to do well. Getting real live sand is part of the key to success with these systems. Check around the magazines for suppliers. There are quite a few by now. The "Plenum" or the "void space" underneath the two layers is really a very important component of this whole system, as I will try to explain: The Plenum is basically a mass of water underneath the layers of coral/shell and sand, just that and nothing else. This water mass acts very much as an oxygen attraction mass. Indeed, oxygen wants to diffuse evenly in a water mass. As the Plenum has less oxygen than the water in the aquarium, it draws oxygen through the live sand and also through the coral/shells layer. This keeps both these layers sufficiently oxygenated for them to sustain the life forms that are in it and not go anearobic, yet the oxygen that passes through the layers is so small (low) that the layers remain an-oxic. This eventually leads to the nitrate reduction that is experienced in these systems by many, and in my experience as well. Systems set up without the Plenum will eventually reduce nitrate as well but the possibility that anaerobic areas develop within the sand is always a possibility. Setting the Live Sand filter up the Jaubert manner is not that easy to do because of all the rock in the aquarium and the difficulty of inserting the grid on which the layers rest. To do so properly the tank really needs to be taken apart which is a chore not too many hobbyists look forward to. If you are presently running a Berlin System and wish to convert to the Live Sand method you need not dismantle the Berlin set up at all. What you will be doing is adding on to it. As I indicated in the article on Live Sand to set the system up properly you will need to dismantle the tank and install the grid that is necessary to build the Plenum (void space of water). If you follow the steps described in the previous article and perhaps read the ones in previous issues you will be able to set your system up in the manner it should be set up. Shortly I will put all the articles relating to Live Sand on our Bulletin Board Service so they can be downloaded for free. You should find them there by the time you get this newsletter. They will be in the newsletter library. While making the change-over from Berlin to Live Sand and Berlin I recommend that you give all your live rock a real good cleaning and remove detritus. It may also give you an opportunity to get rid of bristle worms and mantis shrimp, crabs etc. that you may wish to get out of your system. Take advantage of this opportunity to do so.