If you want more reading, try these:

http://www.canreef.com/vbulletin/sho...d.php?t=28791&
http://www.canreef.com/vbulletin/sho...d.php?t=26299&
http://www.canreef.com/vbulletin/sho...d.php?t=26313&

Tony answered the above questions well, but I can definately add some info regarding ORP.

The denitrification process taking place in the sulphur media is one of reduction and requires an anerobic condition. An ORP value of -50 to -300 is perfect for the stabilization of these anerobic bacteria. Higher than -50 and you get too much oxidization or oxygen present, and lower than -300 and you get a byproduct of Hydrogen sulfide. (H2S) The ORP probe is in there to monitor ORP so I am better able to adjust my 'flow, or drip rate' through the reactor. This will inable me to have the best possible environment for these anerobic bacteria at all times. Atleast that is the theory behind it...

So I now have the unit running on around 15g of water I just pulled from my tank during a water change. I have the drip rate set at about 3 per/second and I plan to leave it that way until the effluent tests zero for nitrate. The water is currently reading about 30 ppm of nitrate.

Here is a picture of the setup:
http://www.playhardrc.com/misc/aquar...nitrator5s.jpg

note* Probe ports and flow meter will not be used until unit is cycled.

What test kit are you planning to use to test the effluent?

FWIW I can't get my effluent to zero nitrates yet. It's been steady at 13ppm for the last week so I slowed it down a bit last night and will retest after 24 hours again. Actually before I hijack this thread any worse I'll go update my own with the latest results because there are some headaches there again. :neutral:

Great News!

(The following tests were performed by the same nitrate kit that I used above and in the same manner. Salifert)

I have just tested the effluent and it's reading ZERO nitrate! (3 drops per second roughly)

This is after roughly 1 week of operation.

Now for the really amazing part... the source water in the red bucket is reading around 0.2 nitrate. (just barely see a pink tint when viewing from the side)

So this unit reduced the nitrate in 15g of water from 30 to 0.2 in the same time frame. Very cool.

The one thing that I did that I believe made a big difference was after I had it running I fed a dropper full of bacteria straight into the reactor. I used the bacteria that comes in the Polyplab Reef-resh system and it apparently contains 6 different strains of anerobic bacteria. So I believe this helped it establish a culture, quickly. I'm sure you could use bacteria that comes with any of the zeovit type systems as well.

Cool idea to seed it. Seems to have made a huge difference. Awesome results..

For comparison I'm still not reading zero on my output after 6 weeks (although output < input). And weird that your Salifert doesn't have interference whereas mine did. I dont understand why I'm always the statistical anomaly... :neutral:

I thought the interference was isolated to the Nitrite test? I never did test for Nitrites, only Nitrates.

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Very cool thread, I'm learning a lot.

Further to this comment; Could you use the system to work as a Ca reactor on a smaller tank? I've been debating building a coil denitrator for some time now, but this contraption would serve two purposes for my tank if it could be configured to work.

That's what they say, but remember I was getting NO3 readings over 100ppm? I'm guessing that had to be interference. Or I'm just REALLY a statistical anomaly.

Just another story about statistical anomalies though. I've never had a peppermint in 10 years in the hobby eat a single aiptasia. I've been through dozens of peppermints through the years. I always read stuff like "Hoo yeah my peppermints cleared my tank of aiptasia in half an hour!" Anyhow with the recent thread about the peppermints from Gold's eating aiptasia with at least two testimonials from people, I went and bought 2 and put them in my 110 (which already has a pair, so now 4 peppermints). I should point out that the tank has all of 3 aiptasias. If the peppermints would just eat the 3, they'd have my glowing admiration forever. This morning? I found a peppermint molt being chowed down by one of the aiptasias. :lol: Still waiting to see evidence of these stupid shrimp ever eating aiptasias. I think it's just far more likely everyone else who claims they eat them is just in on the joke at my expense. :razz:

Getting back on topic though, I wonder if the difference is that I never ran my denitrator on a static body of water like you've done. Ie., I'm running mine on a live system that is producing nitrates every day, whereas cycling it on a bucket will start off with the nitrates at one level, and then only decrease as they get used up. So in that scenario all you have is a consumer, whereas I have a producer and a consumer and trying to adjust one variable while having another variable out of your control makes it just that much harder to get that viable trend showing. I'm sure there's an explanation. At the very least I know that the numbers seem to be slowly decreasing but I'll still just be happy to see it hit zero, if and when that ever happens.

You could, but I still think it's not the greatest idea. The reason is you're trying to tune it to reduce nitrate (and the fact that it adds some Ca/Alk is just a happy bonus), not trying to tune it to maintain Ca/Alk levels in the tank. Ie., Ca and Alk will get used up at rate "X", NO3 will be added at rate "Y", you want to tune your sulfur reactor to match "Y" and you're stuck with whatever Ca+Alk rate that it produces. If that's less than "X" then it's not going to maintain the tanks Ca and Alk. Whereas the Calcium reactor is directly tunable to the Ca and Alk.