Sulfur denitrator flowrate question

[delphinus]

Hi,

I'm running a DIY sulfur reactor (a modified calcium reactor) using Caribsea LSM (pure sulfur) and Caribsea ARM (calcium reactor media) in a second stage.

The first stage contains about 1.75l of LSM, is recirculating with a mag2, is an upflow/fluidized style. Flowrate is controlled from the input so the output of the reactor is fully open (so to not pressurize the chamber).

I have been running this now for 3 weeks and it just doesn't seem to want to cycle. I have been testing NO2 output and it's consistently very high (2.0ppm to 4.0ppm). I figure no sense in testing NO3 until the NO2 is gone.

My question - If the NO2 does not reduce, what could be things to watch out for? Is my feed flowrate too slow? I currently have it set to a VERY low flowrate so to keep the sulfur in a low-oxygen environment to encourage the anaerobic bacteria to colonize. Flow-through the unit is approximately 2-3ml/min. Should I be looking to increase the flowrate or do I need to wait until the reactor is producing zero nitrites?

I assume the nitrate reduction won't even begin to happen until the nitrite reduction cycle is complete.

I should mention that the tank this unit is running on has a chronic nitrate problem and nitrate levels are currently around 50ppm. No shortage of nitrate to feed the reactor in this system.

 

[delphinus]

Bump ???

 

[toccata]

Tony I don't know if this will help you but due to space issues I broke down and bought midwest denitrator. Even though they use a plastic thumb screw on airline tubing (very hard to keep constant adjustment) initially flow rates are a few drops per second. This varies on how mature the reactor is. A rule of thumb would be is if you smell excess sulfur (rotten eggs) the flow rate is to slow. I'm happy to say that after trying to keep a large bio load and different types of coral, I have 0 nitrates. This took a few months but the tank is 350gal so this is probably why. My nitrates were 20-40 ppm and I was constantly told I could not keep SPS corals with nitrates. I only have a few now and they seem to be doing ok. The only down side to this is the macro algae in my fuge hardly grows now.

HTH

Patrick

 

[delphinus]

Hi, thanks for the reply.

Unfortunately I think the problem with my reactor goes beyond finding the right flowrate. It's been running for nearly 8 weeks and the effluent still does not test at zero for nitrates. There is a -slight- reduction in nitrates but not a complete removal in the pass through the reactor, which tells me it's still a flowrate issue and it is too high. However since we're talking about flowrates in the 0.5 to 1.0 drops per second range, slowing it down further seems counter productive. It will never reduce the nitrate level in the tank if it's running at one drop per 10 seconds for example.

I posted the same question in the main forum and found out in that thread that the sulfur will interfere with a nitrite test kit. So testing for nitrite is meaningless, so at least I got that part figured out. But I'm still stuck with the problem with why it's not functioning the way these things do for others. It's a strange problem but I think I might just abandon the sulfur reactor for now and concentrate on reworking the baffles in my sump (I have a microbubble problem, which I wonder may be contributing the sulfur reactor not working) and upgrading my skimmer and so on. If I still cannot get the nitrates down after that then I'll look at at getting the sulfur reactor going again. Seems they work well for most people so it's just a question of figuring out what is different about my situation and addressing that.

 

[klasiksb]

What size is your reactor, what size system are you running it on and what does 1.75L convert to in pounds of media?

I tried the smaller midwestaquatics sulfur reactor on a system that was at the top of the rating for the small reactor. I never got it to work after 3 months. I know believe that the unit was too small for the system (not enough sulfur media).

I will be putting a unit on that is 6x21 (closer to the MA XL unit) on a smaller volume of water and trying it again. Should have it going in a week or 2.

I'll update this thread if you'd like with my progress. Really hoping this one will work for me.

 

[delphinus]

1.75l of media is about 1/3 of a container of Caribsea LSM. I think that they are 1 gallon, or about 10lbs, so roughly speaking looking at 3-4lbs of media.

To be honest I was concerned it was too little media but I heard it would be OK. I can't find anywhere where it says what sort of minimum threshold there may be for this, so I don't know, maybe that's it? I could try running it on a larger reactor with more media, and see what happens..

I should mention I'm running mine on a 110g tank. Theoretically the bioload is low (1 fish, couple shrimp, an anemone) but I have chronically high nitrates. I think it's the anemone (it's a 24" inch ritteri anemone, so that's probably the culprit).

I would indeed be interested in hearing your results. Please do post back when you get a chance. Thanks!

 

[klasiksb]

I've attached something you might want to read. Don't know if you've seen it before or if it will help, but check it out.

It is from Marc Langouet. I believe he is one of the first to start using the Sulfur reactors. I had some emailing exchanges with him after I tried the reactor.

Ok, that's not working. Shoot me a PM with your email addy and i'll email it to you.

 

[reefplicate]

delphinus

that seems odd. my sulphur reactor took about 2weeks to start working everytime i do the bi-yearly maintenance. i pour everyting out and wash with fresh water as it gets clog with bio/bacteria film and fuse into cylindrical block.

are those recirculation reactor or just single past through ones??

i remember some time ago that for those recirculation models, u'll need about 1L in volume of sulphur to treat 400L of tank water.

my unit has 2L volume of sulphur and has a recirculation pump (maxijet) running at 1200L flow rates within it. i don't test for NO3 cuz i rely on my MV monitor to determine the optimum redox for the bacterias within the reactor. it makes life much easier and gives me more time to look/enjoy at my tank.

 

[delphinus]

The sulfur media chamber is recirculating. I was thinking of switching this to a larger calcium reactor that I have, but if you say the ratio is 1 litre to 400 litres of tank water ... then I'm confused because what I have is about 1.75 litres of sulfur to about 115g of tank water (roughly 500 litres if my math is correct {4.4l = 1g ?}) so you would think that it should be working then?

It definitely isn't working, however. The last time I measured the effluent of the reactor, it was outputting approximately 25ppm NO3 (tank = 30ppm NO3, so only a slight marginal reduction), and this is at a flow-through rate of 1 drop per second.

My recirculation pump is a mag2, so approximately 250 gph, is it possible this is too much?

What kind of redox values does yours run at? I could try measuring my ORP in the reactor to see if there's just too much oxygen in there ... I really don't know what more there is I can look at.

 

[reefplicate]

delphinus

currently i have the internal redox between -250 > -320. it's never at fix levels and needs to fine tune daily. end of day it gets lower and B4 light cycle it gets higher (when i say higher, it's still negative range).

i'm gonna try using soleniod valve with a MV controller to make it more precise. i'm just using water T off from one of the pumps, no doser.

why not just turn off the effluent for a day then set it at 1 drop a sec after and adjust/increase when needed. when i reset the reactors after wash, i use old water from my tank and leave the makeup for the reactor off for 24hrs but with the recirculation pump running so to drop the O2 levels within the reactor. after about a mth operation the effluent is almost running at slow flow, not drips. i don't measure the NO3 at all, just monitor the MV/redox in the reactor.

with the amount of fish and corals i have in the tank i know the NO3 is under control (surly not undetecterble) as i only get bryopsis growing in 2-3 very small areas of my 180G tank and i believe it's due to the PO4 that i constantly have problems with around 0.3-0.5 using chlorometer. never other types of algae except for cheato in the fuge. colours of SPS coral are good/OK just not fantastic.

cheers

 

[home_alone]

I too am running a calcium reactor converted into a nitrate reactor. You MUST slow your flow rate until it has an output of 0 on both nitrites and nitrates. Then slowly increase your output daily as you maintain this undetectable level. Should take at least a month to have undetectable levels in your tank. Start slow. Build a healthy bacterial level that matches the flow rate a day at a time. Worth the effort.

It will work. Promise!

 

[delphinus]

Everyone says it should work but ... It doesn't! It has been two months since startup (three if you count my first attempt) and I still output nitrates like crazy and it's a slow slow slow slow slow (did I mention slow?) drip rate. There's clearly something wrong. It's either a question of inadequate media volume or maybe the microbubble problem I have (bad sump design ) is preventing a proper anoxic zone even with the slow flow rate.

I've basically given up on it. I just haven't had the time to actually take it offline. I might try again but next time using a larger reactor.

 

[home_alone]

I really don't think you need a larger chamber. I did not flow any water for the first three days and I also used a product from Seachem called Stability. It is starter cultures of all the different arobic and anarobic bacteria needed in an aquarium. I thought that the correct bacteria was probably present in my tank but this way I was sure that some would be present to start my culture. Maybe that is your problem. Not a good bacteria strain.

 

[klasiksb]

Any updates? Still waiting for my unit to arrive.

 

[delphinus]

Not really. I had mentally given up hope it would ever start doing something so I stopped measuring the nitrate output every day. (Figured that since at least it wasn't hurting anything that it could wait until I had some extra time to fiddle with it and take it offline and clean it up.) Anyhow at one point I discovered the input line had vapour locked and there was zero flow through the reactor (it was still recirculating though) for anywhere up to a week. I fixed it and retested and got zero nitrates. So I had a flicker of hope it was working. Set the drip rate to 1 drop per second and 24 hours later it was back up to 20-25 ppm NO3 in the effluent.

Which pretty much solidified in my mind that this reactor has failed. I don't know if it's a volume issue or what, but clearly it's not ever going to work. Since it's basically impossible to set it to a flowrate slower than one drop per second or two (and hope for it to stay consistent without fiddling with the needlevalve every few hours), I don't think it's a question of the flow being too fast. What I do think though is that because of the smaller volume of the chamber, that the overall turnover is too quick and thus prevents a proper anoxic zone and thus the bacteria simply can't establish at the numbers needed.

A few people have suggested to me that maybe the problem is the mag2 recirculating pump recirculates the unit too quickly ... I could try slowing that down with a ball valve, I suppose, but I'm skeptical it could be the silver bullet I'm looking for. I thought the whole idea of recirculation was to increase the surface area contact (although I suppose contact "time" remains unaffected by recirculation).

Again I really just feel it's a question of a minimum volume threshold. I might just try again with a larger reactor if I get some time to change things around.

 

[klasiksb]

Well, I FINALLY got mine running today. I'll update with my results as this thing starts working (hopefully).

 

[home_alone]

Watch your nitrates closely. Any trace of nitrates at all and your running to fast for your reactor. Everytime you increase the flow rate wait until a 100% change of water in the chamber has occured and test nitrates. You can get in trouble in a hurry if you don't watch close.

 

[davy182]

Now that you mention test kits. Any thing that tests total nitrogen with not give any accurate reading. The most accurate test kits when using sulfur is aquarium pharmecuticals. Hard to believe I know but I have tested every one and that is the one I found to be the best. Set the drip rate to 20/ min test at 12 hours if nitrates are above tank or below tank level double it to 40/ min test in 12 hours if tank above or below tank level double to 80/min next step is get it to barely a stream. This is a sure thing i have done this for 5 years. IF you have any questions pm me.

David

 

[mavgi]

delphinus

i run on my 120 gallon tank 2 phosban reactor with this media and it's reduce nitrate in my tank .

3 weeks it's not enough time and i don't think you need bigger reactor for your 100 gallon tank .

it's take time and you need to be patient with it at the begin i have the same problem as you describe and i thought to change the media to... but after talk with caribsea i give it another chance and it's work .

you want to drip 1 drop per second and not more let it run 1 month till it's will build bacteria in the reactor after that increase to 5 drop per second . if you have a filter sock in the system you can squeeze it inside the ractor it will help to build the bacteria quicker (but still you need to be patient with it )

after that you can split the exit pipe for 2 and then drip on each pipe 5 drop per second (and this just when the system wil show reduce of nitrate ) at this way the nitrate will never increase in the system .

 

[delphinus]

Sorry dude, I disagree. The first post you saw where I said three weeks, that was back in January. I let it run until April and it was still not performing. I tried again two weeks ago with a larger reactor and it started reducing nitrates almost immediately. At one drop per second it was emitting effluent with zero nitrates within 7 days, but not only that, it was emitting effluent with nitrates lower than the input water within 2 days and each day thereon, I tested the effluent and tank water, and the nitrates successively tested lower than the day before until it started reading zero.

So I'm now more convinced than ever that it *was* a minimal size issue. I wish I would have tried a larger reactor months ago, I would have saved myself a lot of trouble. Maybe the difference is that yours is non recirculating. I'm curious though how do you have your feed? I have trouble with a consistent drip rate, I have to adjust it every few days to reset it to one drop per second (usually it slows down to a stop).