Combining Carbon Dosing with Sulfur Denitrification

[DiZASTiX]

I read your article here: http://reefkeeping.com/issues/2005-12/rhf/#1

I use the following techniques for exporting nitrates:

• Vinegar dosing (60 mL/day in 40 gal)
• Biopellets
• ClearWater Algae Scrubber

In my aquarium, the key obstacle faced is high generation of nitrates. Recently, it seems that something died, causing higher than normal nitrates. This had me raise the vinegar dosing rate. Adjusting vinegar dosing rates worked well, but based on the knowledge you transferred us, we can look at how much nitrate have been removed by first performing an alkalinity test.

Alk in my tank in the past 2 days has increased from a ULNS-approved 7 to now 9.x.

Previously, what I did was dose pH down type products, which removed the alkalinity at the expense of pH and oxygen. This caused problems (severe), but I was able to take the tank down from over 300 ppm nitrate to near 0 in 1-2 weeks. Organisms not very happy.

Instead however, what if I add a sulfur reactor?

Supposedly the sulfur reactor lowers alkalinity, whereas carbon dosing raises it. Is it conceivable to balance this aquarium setup so that the alkalinity drop from sulfur reactor is balanced by the alkalinity increase by the carbon dosing?

 

[RobZilla04]

Too big a change to quickly. At this point don't try adding or removing anything else. Shoot for some stability long term (months). pH bufferes / removers will certainly impact Alkalinity. Alkalinity swings certainly irritate corals.

Try to figure out what caused the nitrates to be so high to begin with. If it was death of something, did you find and remove it? Or are you certain is gone at this point? If not gone, the nutrients (N & P) will continue to bounce back until it is.

Where did you read/see that Organic Carbon dosing increases alkalinity?

 

[DiZASTiX]

Actually what you described "Too big a change to quickly. At this point don't try adding or removing anything else. Shoot for some stability long term (months). pH bufferes / removers will certainly impact Alkalinity." refers to a little while ago and it's not really relevant here.

Nitrates and phosphates won't continue to rise at some point. The item will decay until it's been consumed. At that point, we're good. It's just impractical to find what's died. I'd have to deconstruct the rock work. Right now I'm just sort of waiting it out, fighting increased nitrate and phosphate production with increased carbon dosing.

I think a lot of these require some context for people other than Dr Randy Holmes-Farley.

Pertaining to the final point though, "The alkalinity gain is 0.8 meq/L (2.3 dKH) for every 50 ppm of nitrate consumed." I was actually able to sort of estimate the amount of remaining nitrate to export:

5 packets sugar ~ 1 dKH increase
2.3 dKH = 50 ppm
1 dKH = 21.7391304347826 ppm

5 packets sugar ~ 21.7391304347826 ppm
1 packet sugar ~ 4.3 ppm

Need to eliminate 192 ppm

1 packet sugar / 4.3 ppm = x packets sugar / 192 ppm

x = 192/4.3 = 45 packets of sugar

Since the Hanna Checker Alk test is substantially easier and faster to complete than the RedSea Nitrate test, you can actually estimate the nitrates exported by watching the alk rise (assuming you know the alk nature consumption).

Dr R H-F can explain how the chemistry works, but basically alk is released back when you carbon dose, just like it was consumed when nitrate was produced.

 

[RobZilla04]

Supposedly the sulfur reactor lowers alkalinity, whereas carbon dosing raises it. Is it conceivable to balance this aquarium setup so that the alkalinity drop from sulfur reactor is balanced by the alkalinity increase by the carbon dosing?

Okay, even if everything in the post above is accurate, why do one thing that lowers Alk, another to raise Alk, just to have it balance? Seems like a lot of time, effort, and money to get back to the same spot IMO.

BTW the build link in your signature doesn't work.

 

[DiZASTiX]

Well, raising alk from 7 to nearly 10 is fairly undesirable. One way is to wait for alk to fall by itself, but that takes a long time. That means there's effectively a cap to how much nitrate can be exported via carbon dosing. Therefore, what we can do is destroy some of this raised alk. One way to do this is to use muriatic acid. That's fine, but it raises CO2 by a lot. I run double CO2 scrubbers and even then, it takes a long time to displace the CO2 created.

As for this point: "Seems like a lot of time, effort, and money to get back to the same spot IMO."

Isn't that the point of a past time?

For reals though: I have most the components. I just bought a Vibe. so I'll be moving my Zeolites from a media reactor to the new Vibe. That frees up a reactor, and I would simply purchase some of the sulfur media to place in it (along with dead coral bits, creating an ersatz calcium reactor).

 

[RobZilla04]

Or simply control nutrient input.

 

[DiZASTiX]

Some might wish to do that, yes. I'm not about that life. I'd rather use chemistry plus a chance to use that degree in engineering.

 

[RamsReef]

Whew, looks like you are on your own with all those science experiments. I had one of those tanks, it sucked, lost 2k coral, dinos, cyano, dinos, gha. My tank beside it, 2 hob, 1 filter 1 refugium, has 0 issues.

Reefing is a truly keep it simple for success hobby IMO.

 

[RamsReef]

Some might wish to do that, yes. I'm not about that life. I'd rather use chemistry plus a chance to use that degree in engineering.

My engineering + 2 trades tickets + 1 diploma only messed up my tank haha. Corals don't care how smrt you are.

 

[DiZASTiX]

That's why this thread was directed to Dr RHF =P

Separate thread I would ask what to do with a Neptune Apex Dissolved Oxygen probe .. what kind of experiments I can do for the good Doc and R2R

 

[RamsReef]

Looks like that engineering degree didn't teach you how to tag.

@Randy Holmes-Farley

 

[DiZASTiX]

Looks like that engineering degree didn't teach you how to tag.

@Randy Holmes-Farley

It's not an important request. I don't want to bug him more than I've already. The Doc has a new job and all.

 

[Dan_P]

Actually what you described "Too big a change to quickly. At this point don't try adding or removing anything else. Shoot for some stability long term (months). pH bufferes / removers will certainly impact Alkalinity." refers to a little while ago and it's not really relevant here.

Nitrates and phosphates won't continue to rise at some point. The item will decay until it's been consumed. At that point, we're good. It's just impractical to find what's died. I'd have to deconstruct the rock work. Right now I'm just sort of waiting it out, fighting increased nitrate and phosphate production with increased carbon dosing.

I think a lot of these require some context for people other than Dr Randy Holmes-Farley.

Pertaining to the final point though, "The alkalinity gain is 0.8 meq/L (2.3 dKH) for every 50 ppm of nitrate consumed." I was actually able to sort of estimate the amount of remaining nitrate to export:

5 packets sugar ~ 1 dKH increase
2.3 dKH = 50 ppm
1 dKH = 21.7391304347826 ppm

5 packets sugar ~ 21.7391304347826 ppm
1 packet sugar ~ 4.3 ppm

Need to eliminate 192 ppm

1 packet sugar / 4.3 ppm = x packets sugar / 192 ppm

x = 192/4.3 = 45 packets of sugar

Since the Hanna Checker Alk test is substantially easier and faster to complete than the RedSea Nitrate test, you can actually estimate the nitrates exported by watching the alk rise (assuming you know the alk nature consumption).

Dr R H-F can explain how the chemistry works, but basically alk is released back when you carbon dose, just like it was consumed when nitrate was produced.

Interesting data.

I found on small scale experiments that when dosing calcium acetate, acetate is consumed 10x faster than nitrate. Assuming a packet of sugar is 4 g of sucrose, 7x more sucrose in acetate equivalents is used than nitrated consumed, which seems like amazingly close observation for such imprecise experiments. Or a lucky coincidence.

The only connection to the alkalinity discussion here is that likely most of the sucrose carbon is respired and has no impact on alkalinity. As stated, the NO3 assimilation results in alkalinity generation.

As for using a sulfur denitrator to bring down the alkalinity from nitrate simulation, in principle yes, but in practical terms just adding sulfuric acid to bring down alkalinity would accomplish the same thing. If you are interested in sulfur chemstry, you could try the BADES approach and tell us how well it works. @Belgian Anthias tells us that we should consider it over carbon dosing.

 

[DiZASTiX]

As for using a sulfur denitrator to bring down the alkalinity from nitrate simulation, in principle yes, but in practical terms just adding sulfuric acid to bring down alkalinity would accomplish the same thing.@Belgian Anthias tells us that we should consider it over carbon dosing.

If I use a sulfur reactor however with calcium media, would that not neutralise the acidity, and thus help mitigate against severe pH drops (as seen when I was previously dosing muriatic acid?)

@Randy Holmes-Farley , @Belgian Anthias , @Dan_P : I'll be sure to gather good data!!
Do any of you have ideas of what to try to collect?

My nutrient management strategy involves:

• ClearWater Algae Scrubber
• Vinegar Dosing controlled via Apex Neptune
• Biopellets in Somatic UF-1 ***
• Sulfur with Reef Octopus Varios CR200 8" DC Calcium Reactor ****
  
• GFO **
• ZEOvit Zeolites with Avast Marine Vibe 4L *
• AquaForest Life Bio Fil with Avast Marine MR16
• MANGROVE PLANT =D

Not for nutrient management but to disclose:

• 2x CO2 scrubbers, air forced into skimmer by air pump
• Ozone forced into skimmer by air pump
• Will be adding carbon (BRS ROX 0.8) per ZEOvit system guidance

* Will need to figure out a sound damping mechanism. Security came up at 3 am and said that the downstairs people complained about loud hammering or some other noise.

** Not sure if this is really useful, if it'll compete and draw out any phosphate needed for carbon dosing or growing algae. I did dose lanthanum chloride, since I needed a product as an emergency, and could get this Prime shipping--I do like it. I read Randy's comments, and agree with the line of thinking.

*** Laugh all you want. I got the biopellets for free when I bought a reactor. I'm a hoarder and I feel bad for throwing stuff away, so I figured I'd try biopellets. TLDR: biopellets suck. I cannot believe people use them as a primary export strategy. Weeks in, they till don't do anything. I do understand that biopellet-type-bacteria can be rare in aquaria but still. I did dose the reactor canister (pump off) with tons of ZEOvit and AquaForest bacteria. I left it there for hours. Didn't do anything. I do think one day they could be a good backup. I'm on my regular work travel and the dosing pump failed and the sulfur reactor effluent pump also failed. Who knows. Pellets could save the day.

**** Not setup yet. I don't even know where to hide it.
​

The non-experimental goal will be to maintain ULNS in accordance with the ZEOvit system.

Some of those are enormous pieces of equipment. They are now hiding (poorly) behind sofa along with the 4x Neptune DoS pumps, dosing containers, Neato vacuum bot... Girl will be mad methinks. I still need to figure out where to hide the calcium reactor.