I’m not trying to disputes your impressive results but anaerobic denitrification is not the reaction in your denitrator. This “NO3− → NO2− → NO + N2O → N2 (g)” reaction only happens in the absents of o2 and ime the Natureef Denitrator never reaches an oxygen depleated environment. When I used it orp never went below 100, for anaerobic denitrification to occur orp needs to be negitive. Imo the biomass sequesters the no3 and that is why no3 is reduced. One needs to remove the biomass to complete the process. With vinegar/vodka one uses a skimmer; with the Natureef Denitrator you remove it manually every few months. Mine would completely fill with "snot" after a few months. it seems very possible that the vessel offers more control and methonal is a better carbon source.
Our experiment is based on Adolf Klostermann's published articles. He proved this reaction takes place in the chamber. We dont have the expensive test equipment to prove a hypothesis, we are assuming it works.
Based on the information you provided I would say you overfed your denitrator and the excess methanol got flushed back in your tank feeding the cyano outbreak. The overfeeding may have also caused the excess biomass buildup you experienced inside your denitrator. Furthermore, IME the stock internal pump gets clogged up after a short time (few months). Once the pump is clogged the chamber loses the proper circulation and the reaction happens only in the very top few inches of the chamber. This happened to me last year and I had a huge build up of biomass on the top just where the methanol was dosing. I've found if you modify the eggcrate with a 3-4" hole in the lower section and change the internal pump to a koralia nano it solves this problem. I still monitor the koralia from time to time; Since koralia's are held in place by a magnet they are easy to keep in position and easy to remove to clean if needed.
I've been helping another person start up a biodenitrator (marvin) and he's been logging the ORP. Marvin's display tank ORP is 200+. While it hasnt gone negative, it has dropped to almost zero inside the denitrator. I've read those same articles that say the reaction peaks when orp is -200. We havnt seen that yet; it could be a limitation in our equipment. Also, Adolf theorized in his published article in FAMA that nitrate reduction and deoxygenation occur simultaneously in the established biomass.
The spike in nitrite levels is an intermediate product of the denitrification cycle. NO3---->NO2 How else would you explain it?
Nitrogen gas is the end product of this cycle. In my denitrator you can actually see the accumulation of nitrogen bubbles on the eggcrate. Sometimes I get so much Nitrogen gas build up on my eggcrate that it lifts the eggcrate out of the water.
While the biomass incorporates some nitrogen it definitely does not "sequester" nitrate. As far as methanol vs other carbon sources: Adolf chose methanol because of its low oxidation state; since it is a single carbon atom it is easier for the bacteria to work with. The chamber would probably work with ethanol, acetic acid or simple sugars. Again, we are trying to duplicate Adolf's work.
When I first started my biodenitrator over 2 years ago I did not really have an understanding of HOW it works. I was just told by friends (thanks Rogger) that it works and here's what to do. The first year my denitrator crashed twice and I didnt know why. I almost took it down after the second crash. Then I started doing research on how the chamber works and got a working understanding of the denitrification cycle. Once I understood the reactions that were taking place inside the chamber, I was more prepared to deal with problems that arose.
I am now sharing that information with all who will listen. Dealing with nitrates is one of the most challenging problems faced in this hobby. What is one the first things someone asks you when you have a problem with your tank.....what are your nitrates? To prevent Nitrates we will: limit feedings(starving the fish),vacuuming after a feeding to prevent waste, limit the number of fish we keep and/or do regular massive water changes. I think the denitrator is a great addition to help with the nitrate buildup. I've been running a biodenitrater chamber on my 200gal system for over 2 years. My nitrates stay in the 2.5-5mg/L range using the salifert test kit. I have 30 fish, 4 of them tangs; I feed 4 cubes of frozen food twice a day and a sheet of nori daily. I do a 2.5gal daily water change (automated) and I don't worry about nitrates.
I'm sorry to hear it didnt work for you. I'd be happy to help you with it if you wanted to start it up again. I'll also be starting a thread soon on my experiments with adding strontium nitrate to the chamber to remove phosphates.
