My new sulphur denitrator setup

[Psyire]

Well I've finally recieved my new sulphur denitrator.

I've been having a nitrate problem for the past 6-8 months and have now resorted to trying a sulphur denitrator in order to keep things under control. I do have 4 big fish but I don't over feed, infact I feed a lot less than I want too. If I feed bare minimum I can keep things under control, but not up to my standards. So my goal is to be able to feed generously and not be worried about Nitrate buildup.

I started talking to Brent Barr in November about building a calcium reactor that I could convert into a nitrate reactor and he was all for it. (almost all my tank equipment, including my sump was built by him) The biggest reason I wanted to use one of his reactors is because I can recirculate the sulphur chamber separately from the calcium chamber which will stop any dissolved calcium from precipitating back out in the sulphur chamber.

I decided that the biggest reactor was the one I wanted to test, this ofcourse may be a bit big, but it should allow for a whole lot of nitrate reduction, and this will be needed as my fish and corals grow even larger. My tank is a 180g, with a 60g sump.

More info on Brent's equipment can be found at his Barr Aquatics website, or on the Austin Oceans website. (they now build and sell all of his designs)

Equipment involved:

Barr Aquatic CR2200 (with water flow meter)
Caribsea LSM (sulphur media)
Gen-X CRM (calcium media)
Aqualifter pump
1/4" tubing

Initial pictures:

http://www.playhardrc.com/misc/aquarium/sulphurdenitrator1s.jpg

2 probe ports:
(ORP & pH)
http://www.playhardrc.com/misc/aquarium/sulphurdenitrator2s.jpg

Media:
http://www.playhardrc.com/misc/aquarium/sulphurdenitrator3s.jpg

Reactor full and ready for action:
http://www.playhardrc.com/misc/aquarium/sulphurdenitrator4s.jpg

I currently have the reactor running full bore on some water I removed from my tank in a water change. I plan to flush it with 'new' tank water in a couple days and then put it online.

Should be interesting...

[Delphinus]

Looks great. So is Brent making stuff again? When I wanted to buy a skimmer from him a couple years ago he had decided to take a break .. nowadays I know you can get the designs from Austin Aquatics but it's nice to hear he's back in business. He has some neat stuff.

Anyhow, good luck with this. Like that coarse media .. If I wasn't sitting on I think at least 2 containers of ARM I'd try some .. but I have to use this stuff up.

At least I think I can say I learned something with my sulfur denitrator that I hope can spare you some headaches in getting yours going. Although at one month in now and not outputting zero yet (but output is less than input so that's good) I think that it's good that you've oversized it, because despite that people tell me I should have an adequate media volume, the same flowrate into a larger vessel compared to a smaller vessel will be introducing "less O2 by volume" into the anaerobic zone, meaning hopefully a faster cycle.

I guess I can tell you to be suspicious of your test kits, sulfur interferes with them. Nitrites for sure, so don't bother testing nitrite.

Oh one more thought, Randy Holmes-Farley did this one write up where he sort of explains why the calcium from the second stage should be minimal .. (chemical equations and all), but I can tell you in the 8 weeks now of running mine (between the two "trials"), the calcium media in my second stage has gone down at least 2", maybe 3". So while it's theoretically negligible, IME it's non-zero. I haven't bothered testing alkalinity in this tank though as there is nothing in there that it's a huge concern for (corals can't live in nitrate soup). Just my ritteri anemone.

Which sort of leads me to my question for you though ... in my case, the ritteri is this weird nitrate-producing beast that I've learned to live with. Perhaps a stronger skimmer would help me in this regard but I'm curious what skimmer you're running on your system and whether you've given any thought to upgrading or modifications there (i.e., recirculation, gravity feed from raw overflow water, etc., or even just going to a larger skimmer)?

[Psyire]

Well Brent isn't into production anymore, he just is doing design now, from my understanding. But he does have a few of this and that left over to sell off. (listed on his website)

I like the coarse calcium media as well, and I'd like to get more coarse sulphur media if I can find some.. I have to do some looking around. I work at a plant in which we make 42 tons of sulpher every day, but I really have no way of 'beading' it. I suppose I could use broken chunks but I'm not sure if that would be very effective.

As for my skimmer, it's a Barr Aquatic SK1620. It works quite well and rated for twice my water volume, so I don't think I am under skimming, but it's amazing how much waste is created by 2 tangs & 2 rabbitfish. (plus various other small fish) I also have a fairly large LT Anenome and a Condy Anenome... plus various corals.

[untamed]

I don't understand this at all... I understand how a Ca reactor works...and I understand how a Nitrate reactor works...but I'm not clear on how/why you've got them together in this case. Or what advantage that brings.

I'll go back and look at my Holmes-Farley stuff, but does the Ca reactor somehow consume O2?

[Psyire]

Simply put...

The Nitrate reduction that occurs in the sulphur chamber reduces the pH to a point where the second chamber's calcium will dissolve and raise the pH back up before entering the tank.

[Delphinus]

A sulfur based denitrator uses aragonite media to buffer the output as it will be low in pH, so it conditions the effluent before being returned to the tank. Any sulfur based reactor has both sulfur media and calcium media, either mixed together as in the case of Caribsea "No-NO3" media, or in separate layers using Caribsea LSM (or other pure elemental sulfur granules) in one layer and a calcium reactor media in the other.

What Psyire (and I) have done with our reactors is use a 2 stage calcium reactor design and use exclusively sulfur in the first stage and exclusively aragonite in the second. Typically a 2 stage reactor uses recirculation on the first stage and single-pass on the second, which I think in the case of an anaerobic bacteria colony would only help with the overall efficacy of the reactor.

A calcium reactor does not consume O2 but uses CO2 to lower the pH to dissolve the aragonite media.

Psyire, what sort of nitrate levels are you running? While I'm excited that you're trying this, on the other hand that's not a heavy bioload for a 180g by any means.. I'm sort of surprised you would be having nitrate accumulation problems ... (bluntly put, you shouldn't be).

[Psyire]

Well...

I don't think I should have a nitrate problem either, but I have my theories...

#1, I used 100% base rock for the main display (180lbs). This baserock was from reefer rocks and is extremly porous and looks very nice. However, I believe it might be 'too' porous and not have a big enough oxygen free zone as traditional dense LR from the ocean. This would lead to a reduction in anerobic bacteria and an inherent inability to deal with as much nitrate conversion deep inside the LR.

#2, 1"-2" Sand bed. I did not want to go with a DSB and did not want to go with barebottom (at the time) Now I'm wishing I would have gone BB, as the detritus buildup would not sink into the shallow sand bed. The same problem as noted above essentially... Deep enough to convert to Nitrate, but not further.

Note: I have more tank inhabitants than I posted above, those are just the bigger ones... but you are right, it "should" have been fine. Tank has been setup and running for over a year and a half. Nitrate is anywhere from 50-100 depending on what's going on. (recent water change, etc)

Picture of rock for reference:

http://www.playhardrc.com/misc/aquarium/Baserock2.jpg

[Delphinus]

Hmm .. interesting. I would have guessed those rocks would be OK but who knows. Well it's just like my situation really, mathematically there's no reason for me to have had nitrates above 50 in the first place but it's been fairly consistent, and I've tried just about every other trick in the book (and gone though at least 4 tank setups as well). I guess sometimes it just happens ...

On the bright side it's down to the mid 20's now and appears to be coming down nicely still.

[untamed]

I'm really interested in this.

Sorry for tons of questions...
1) The sulfer based reaction has no need for low pH or CO2 addition, right?
2) Do you add CO2 to the Ca reaction chamber?
3) Is the Ca reaction chamber recirculated? Is the Nitrate reaction chamber recirculated? Both?
4) Do you have an additional Ca reactor, or is this your only Ca reactor?
5) Why the ORP sensor in the Nitrate chamber? Does the sulpher reaction also need to be in the absence of oxygen? If so, how is oxygen removed from this reactor?
6) Do you attempt to vent the N2 produced?...

Here's what Holmes-Farley had to say about it. I believe this was written in 2003.


Use a sulfur denitrator. In these systems, bacteria use elemental sulfur and produce N2 from it and nitrate according the following equation (or something similar):

2 H2O + 5 S + 6 NO3- à 3 N2 + 5 SO4-- + 4 H+

It has also been suggested to pass the effluent of such a reactor through a bed of aragonite to use the acid (H+) produced to dissolve the calcium carbonate, and thereby provide calcium and alkalinity to the aquarium.

While that is a fine idea, it doesn’t add much calcium and alkalinity to most aquaria.

To estimate the magnitude of the effect, we start with a liberal estimate of how much nitrate might be removed. Say 10 ppm of nitrate per week.

10 ppm nitrate = 0.16 mmole/L of nitrate

Since 4 moles of H+ are produced for every 6 moles of nitrate consumed, this will produce

0.107 mmoles/L of H+ per week

How much calcium this could produce?
Assume that it takes one proton to dissolve one calcium carbonate:

CaCO3 + H+ ßà Ca++ + HCO3-

Clearly, this is a substantial overestimate because much of the acid will be used up driving the pH down to the point where CaCO3 can even begin to dissolve. Consequently, we have an upside limit of

0.107 mmoles of Ca++ per week

since calcium weighs 40 mg/mmol, that's

4.3 ppm Ca++ per week.

For comparison, an aquarist adding 2% of the tank volume in saturated limewater daily is adding on the order of 16 ppm of calcium per day. Consequently, this method may not be especially useful for maintaining calcium and alkalinity levels. On the other hand, the acid produced will have a long term lowering effect on the alkalinity, so if you use it, watch the alkalinity.

As to its actual ability to reduce nitrate, I cannot say for sure. I expect that it can be made to work, but the only aquarist that I have spoken to that uses one has had considerable difficulty with it.

[Delphinus]

Ask away! :) (Not speaking for Psyire of course, but I'm hoping he doesn't mind).

I'm really interested in this.

Sorry for tons of questions...
1) The sulfer based reaction has no need for low pH or CO2 addition, right?


Errr .. yes and no. No as in you don't inject CO2 to lower the pH, but you DO need a zone of "little to no" oxygen (aka "anoxic zone" or "anaerobic zone") for the anaerobic bacteria that reduces nitrate, to take hold. They metabolise the sulfur, consuming the nitrates and releasing nitrogen gas, and sulphates (see your RHF text you quoted). NSW already has sulfate to some degree and there's nothing in the literature to suggest that it's harmful in any way.


2) Do you add CO2 to the Ca reaction chamber?
No - the absence of oxygen plus the metabolic activities reduce the pH in the reactor, so the water entering the Ca reaction chamber is already with depressed pH.


3) Is the Ca reaction chamber recirculated? Is the Nitrate reaction chamber recirculated? Both?
The Ca reaction chamber is the second stage of a 2 stage calcium reactor. These are almost always single-pass, otherwise you're basically looking at a complete reactor for the second stage. I imagine there is benefit for recirc on this stage but it's fairly atypical thing, based probably mostly on economics. I've been considering making my 2nd stage recirculation at some point but it's not a priority. The flow-through flowrate is very slow.

The nitrate reducing chamber, or the first stage, is recirculated. This part is basically the same as any calcium reactor.


4) Do you have an additional Ca reactor, or is this your only Ca reactor?
Technically I think you're better off not relying on the denitrator to replenish Ca and Alk on a heavy Ca drawing bioload (ie. SPS, clams, etc.). Personally I have several reactors anyhow as I'm a gear nerd and like trying different things so in my case the answer is "yes I have an additional Ca reactor" but at the moment the tank I run my denitrator on has a very low Ca demand as there are no corals in there for now. So no other reactor on THAT tank but that may change one day.


5) Why the ORP sensor in the Nitrate chamber? Does the sulpher reaction also need to be in the absence of oxygen? If so, how is oxygen removed from this reactor?
I can't answer the ORP thing, maybe Psyire can chime in on that one. In my opinion, ORP is a useless number to track unless you're running ozone on your system.

The sulfur reaction does need to be in the absence of oxygen.

Oxygen is removed by cycling the reactor and using a very slow flowrate. Thus, once the oxygen is depleted, very little returns into reactor from the feed.

There is a slight caveat. Once the unit has "cycled completely" and after a period of time the tank nitrates will read zero. At this point you need to increase the flowthrough rate through the reactor so that nitrate can be consumed at the rate it is produced.

So technically you don't want an completely oxygen-free zone, as if you do that, you'll have the wrong chemical reaction take place, and produce H2S instead. Apparently the levels are so low as to generally not be a concern other that it will stink your place to high heaven. But you do want a "low" oxygen zone until your tank is reading zero nitrates and then you rely on a smaller population of bacteria with the faster flowrate.


6) Do you attempt to vent the N2 produced?...
It is recommended to place the output of the reactor in a high turbulent zone, preferably a sump not the main tank, and above the waterline to aid in gas exchange. Other than that, no special consideration for venting N2 (which is a part of air anyhow), except for that the first stage, i.e. the sulfur stage, should be an upflow so that gas can escape into the second stage (which should also be upflow so gas can escape from there as well). A downflow style will end up with a gas bubble at the top that can't go anywhere.


Hope this helps..

[Delphinus]

If you want more reading, try these:

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

[Psyire]

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...

[Psyire]

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/aquarium/sulphurdenitrator5s.jpg

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

[Delphinus]

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:

[Psyire]

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.

[Delphinus]

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:

[Psyire]

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

[danny zubot]

Very cool thread, I'm learning a lot.

Technically I think you're better off not relying on the denitrator to replenish Ca and Alk on a heavy Ca drawing bioload (ie. SPS, clams, etc.).

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.

[Delphinus]

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.

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

[Delphinus]

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.

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.

[danny zubot]

Hmm, ok. I'd still be interested to see what Ca levels come out of the unit.

Thanks though,

[andestang]

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.

This brings up what I was wondering. I have a MoCalc 300 and was thinking of trying this idea. But could you try and acheive what you want for Ca/Alk and have the reduction of what ever amount for a reduction of nitrate ?

[Psyire]

Well if your drip rate is too fast then it will not function properly and if it is too slow you will get H2S created in the reactor... so that's probably not a good idea.

Your Ca production will also flucuate with your nitrate level reduction so it would be very difficult to get it constant. (unlike a CO2 bubble counter w/ solenoid control)

[Psyire]

I hooked the reactor up to my system tonight, my starting nitrate level in the tank is just under 50ppm

[Delphinus]

Can you take some ORP readings? I'd like to know what's a good baseline. I don't have an ORP monitor but I have an ozonizer with ORP controller so I could probably use that for some rudimentary readings (or see if there's someone with a monitor I could borrow). I'm about ready to just crap can my whole reactor. Just tired of the lack of results. Wish I knew what was wrong with the way I'm running it.

[Psyire]

I can, it will be a bit though, I just had enough time to roughly plumb it to my system. I'll be setting it up more permanent with probes soon.

[Psyire]

Just did some tests:

Nitrate
-------
Tank: 30ppm
Reactor Effluent: < 1ppm

pH Reactor Effluent: 7.6
Drip Rate: 3-4 Drips per second

Glad it's working!

[Delphinus]

Are you measuring at the exit of stage 1 or stage 2? I just measured both mine and there was quite a difference, 10 after stage 1 and 22 after stage 2. I'm not sure if that means my second stage is producing nitrate, or whether the first stage started reducing more and the water simply hasn't passed all the way through the second stage yet. At any rate I changed my feed situation around again so I'll see if I can get to your kinds of results.

[Psyire]

By Effluent, I mean the water dripping back into my tank.

[Psyire]

Finally found some better sulphur media...

Aquarium Obsessed can get the media for the H&S reactors. The price is $39.99/ kg. It's quite a bit more pricey than the caribsea stuff, but there is quite a difference in size/shape. I have some in my hands, and I'll post some pictures soon.

[Delphinus]

I don't see any H&S reactor on page 1 of this thread? The only pictures I see are the ones I assumed were your reactor?

And... with all due respect, why did you feel you needed a better media? You seemed to be getting results? If anything it's me who needs new media, but I thought your reactor was working for you??? Not trying to be rude I'm just surprised you went and got new stuff already??

[Psyire]

Sorry, I got confused between this thread and my RC thread.

Here is the picture I was refering to:

http://i140.photobucket.com/albums/r13/winnerRC/HS%20110CR/110CR2.jpg

I don't believe I 'need' better media, but this media would definately be less prone to clogging over time, due to detritus and other floaties such as dust from the tank water getting caught up in the reactor. I would guess that it would reduce the chance of having 'pockets' of stagnant water that may cause the production of H2S as well. (less of a channeling effect) I don't plan to switch to this media quite yet, perhaps a few months down the road once my nitrates are zero... we'll see.

[Delphinus]

Ah, I see. It is an interesting looking media. I haven't found mine to have clogging issues in 8 weeks yet but I can see how the rounded stuff would be better. The only thing is for me 8 weeks in and I can't get it to produce zero NO3 no matter what I try. My last thought is that the tank has a bad microbubble problem, maybe I just have too much dissolved oxygen in the tank water. Since it seems to be an insurmountable issue and nobody can tell me what's wrong with with mine, I'm probably going to take mine offline. No sense in paying for the electricity to run the pump if it's not doing anything. :( Disappointing on the one hand but on the other hand I'm glad yours is working out for you. Means that it can work.

[muck]

Won't the Corn Pops get soggy after awhile and become useless..? :mrgreen:

[Psyire]

Minor setback...

I increased the drip rate a few times over the course of the last week n' a half and managed to go alittle too far with it. The effluent tested at 5ppm, so I just set it back some. I'm guessing it was around 6 drips per second or so. The good news is my tank is still going down, I just tested and it was 25ppm nitrate.

I tested alkalinity for the first time since I connected the reactor and it did drop some. I have been running between 7-8 dKH and it tested at 6.4 dKH. So I may have to keep a closer eye on it, we'll see how things go.

So far, I am still pleased with the results. I plan to do more testing regarding calcium and magnesium when I get some more free time.

[Psyire]

Still going strong, down to 15ppm in the main tank. Algae grow has definately slowed down noticably. Still happy with the results so far

[Quagmire]

Down from 30 to 15 in 2 1/2 weeks.Pretty impressive,Ive been following yours and Tonys threads,to decide if its worth trying out.

[Psyire]

Also, I had some cyano re-appear in my fuge a couple of months ago and it's all died off now. (so it's definately doing something)

[Delphinus]

Sweet....

[TRS]

Have either of you tested and logged Calcium concentrations within your display tanks and the Sulfur Denitrator effluent?

My current parameters are as follows:

DAY 31 TANK PARAMETERS (March 8/07)
pH: 8.4 (by MILWAUKEE pH meter)
Specific Gravity: 1.025 (by ATC refractometer)
Temperature: 79.8 F
ORP: 362 mV (Red Sea Aquazone Plus 100)
Alkalinity: 3.52 meq/L (by SALIFERT)
Calcium: 450 mg/L (by SALIFERT)
Magnesium: 1380 mg/L (by SALIFERT)
P04: <0.03 mg/L (by SALIFERT)
NO3: 50 mg/L (by SALIFERT)*

DAY 31 EFFLUENT PARAMETERS (March 8/07)
pH: 7.5 (by MILWAUKEE pH meter)
NO3: 100 mg/L (by SALIFERT)*
Calcium: 490 mg/L


My Sulfur Denitrator has nearly cylced. I tweaked it too much a couple of days ago so it should zero out again in the next day or so.

I have not been dosing Calcium in the display, yet its concentration remains a constant 450 mg/L. My guess is that the Calcium will be more readily consumed and will be reduced once the Sulfur Denitrator kicks in and the Nitrates can be kept at zero.

[Psyire]

I haven't yet, primarily due to the fact I've been so busy that I hardly have the time to keep my tank's glass clean. I'm hoping things slow down soon, so I can spend more time 'in the hobby'.

[Delphinus]

I haven't, if I can dig up my old Ca and Alk test kits and if they're still viable I'll post some numbers. The A.R.M. in my second chamber has gone down about 3" in 2 months so there's definitely some addition of Ca and Alk, but seeing as I have no corals in the tank to speak of I haven't been faithfully tracking those #'s, only the nitrates (which it hasn't done anything to reduce :( - in fact, I'll update my other thread since it's been a while - but I'm taking mine offline).

[Psyire]

After running some standard tests on my tank tonight, I thought I would update this thread.

However there isn't much to say. I've hardly touched the Denitrator, opting to let it 'do it's thing'. I am pleased to report that my tank nitrate level is down to 5ppm, and the effluent of the reactor was 0. So I increased the drip rate ever so slightly for the first time in well over a month.

All in all, I'm very impressed with this 'hand's off' approach to dealing with mysterious high nitrate levels. It seems to be working wonders.

[Delphinus]

Sweet.

Apologies if you've answered this already, but what's your mechanism to feed the unit? Separate pump with needle valve, etc.?

I'm using an Aqualifter pump to feed mine now (with an irrigation dripline on the output of the pump, which then pushes into the recirc pump intake). It seems to be holding steady this way (finally!). It just seemed that feeding mine off gravity or just the pump intake before, didn't produce enough of a steady driprate (ie. it always drifted over the course of a few days, or stopped altogether). I almost went to using a lab grade metering pump (went so far as to buy one in fact), but if the $10 solution works I'm going to stick with that (and maybe recover the couple hun I spent on the metering pump, unless I can dream up a way to put that thing to use :) )

[Psyire]

I'm using a very similar method. Aqualifter pump with a needle valve on the output of the Reactor back to the tank. (so the reactor is under slight pressure)