I just read this on a sulpher reactors on reefkeeping .net
its a good read too.
An article published by MARS (18/5/98) and written by Christophe SOLER gives a good picture of the method. I will just simply give historical precision and further information. It is my ex-professor Guy Martin from Ecole Nationale Supérieure de Rennes who is at the origin of this idea; he applied it to fresh water treatment for public water.
I tested this method with seawater, which was new, especially since we didn't know if it would have toxic consequences for our animals, as soon as 1991.
It is only by the end of 1994, after three years of experiments without apparent toxicity in numerous aquariums and species present at home, that I proposed this method to Michel Hignette, curator of the MAAO aquarium. A pilot project was lunched under my care.
Since then the experiment was done on a much bigger scale, at the MAAO, as well as in the Grand Aquarium in Saint-Malo, of which I was technical and scientific director from June, 1st 1996 to mid-December 1997.
I wish to stress the fact that I am using since 1996 beads of sulfur of a 3.5-mm diameter. This form is much easier to use than bars that you have to break using a hammer.
The quantity of sulfur to use depends on the initial nitrate level at startup and on the amount of food added. I consider that a sulfur volume equal to 1% of the total water volume is enough when the initial level is below 50 mg/l (NO3-).
The water flow that must go through the sulfur column depends on the nitrate level of the water to be treated: the more nitrates, the lower the flow must be, otherwise you will find part of the nitrates will be found after the column.
At startup, you can count on 1 liter per hour and per sulfur liter in the column. Then you can adjust in the following manner:
- If the flow rate is too low, you will get a rotten egg smell at the column's exit due to a production of sulfurous hydrogen (H2S). This will rarely happen for really low flow rates.
- If the flow rate is too high, you will detect nitrites or nitrates in the output water.
- If the flow rate is correct, you should obtain 0 nitrates.
However, experiments show that the system is very tolerant regarding the flow rate, which could go up to 5 liters per hour per sulfur liter.
The water sent to the column could come from a filter derivation or directly from the aquarium. The column must allow the produced nitrogen to escape: for these reason a vertical circulation, from bottom to top, seems a better choice, with a flow-rate setting at the input, not at the output. The column's output can be open to the air. The water exiting the sulfur column can be very acidic, but after my experiments getting the gas out of the water (by using an air-stone for example) allows to get a pH close to the original. The water's acidity is then at least mainly linked to the presence of carbon dioxide; thus the idea to use this water to make a calcium reactor by making it flow in a second (and why not a third) columns, identical in size to the one containing the sulfur, but this time filled with maerl or some coral sand (the same that you are using for your sandbed).
This output water also contains sulfates in quantities slightly higher than at the input, but in 7 year of experiments it has never been observed any consequence, even in aquariums that didn't get any water changes for years. It must be noted about that subject that there was an error in the publication made with the MAAO: the sulfur level in natural seawater is near 900 mg/l; this sulfur is present under the form of about 2.65 g/l sulfate (SO4--), quantity, which by itself can explain that the system's addition in sulfate will be without any notable consequenceAn article published by MARS (18/5/98) and written by Christophe SOLER gives a good picture of the method. I will just simply give historical precision and further information. It is my ex-professor Guy Martin from Ecole Nationale Supérieure de Rennes who is at the origin of this idea; he applied it to fresh water treatment for public water.
