Sulfur Denitrator

waynesreef · Dec 13, 2015

I am currently running a sulfur denitrator on my 450 gal system. The issue I am having right now is the effluent come out of the reactor smells a bit of H2S but the nitrate reads at 10 ppm (Salifert test kit). Is this possible? I know the reactor is working there is 15 ppm difference in nitrate level between the system water vs. the effluent output. What should I do next, keep running the same drip rate until the effluent output reads 0 ppm or increase the drip rate trying to get rid of the H2S smell?

Randy Holmes-Farley · Dec 13, 2015

How long has it been running?

waynesreef · Dec 13, 2015

I had this reactor for past 5 years. After the initial setup and dial in period the reactor has been running with 5 L/h flow since. The effluent output always reads 0 ppm and that is why I stopped to check after about 6 months. I did have to add more sulfur after about 3 years of running. Just recently I converted the tank from mostly fish only to full sps. I started to check the nitrate again and discovered the nitrate level of effluent is measured between 5-10 ppm. In order to get the effluent reading to o I cut down the flow rate and that is how the H2S smell occurred with the nitrate level of 10 ppm. Initially I thought may be there is something wrong with the nitrate test kit. I used two different types (Saliert and API) and both got the same measurement. That is why I am kind lost and trying to find the cause.

Randy Holmes-Farley · Dec 14, 2015

It could be that degradation of organics in the reactor is leading to production of H2S, either from sulfate in the seawater or sulfur from the denitrator media.

When the effluent is reading 5-10 ppm nitrate, what does the tank read? If the tank is higher, I'd go back to the setting where the effluent is 5-10 ppm.