New sulfur denitrator working great!

[lawise]

Yup, you might have to stick your nose quite often in there until it dialed in. Shouldn't be problem but getting it dialled properly will take some times. Just be vigilant with the media, it might get clogged with bacteria or detritus.

The aquamaxx that I purchased does have a small pre-filter on it.

 

[Donovan Joannes]

The aquamaxx that I purchased does have a small pre-filter on it.

Nice!.

 

[LobsterOfJustice]

I may find the same problem with mine I think when nitrates drop to zero then my unit may be too big. I guess I can just speed up the drip rate to a stream

Yes, exactly, just increase the flow. Mine is running as a steady stream now that it has cycled.

 

[lawise]

I'm settting up a new tank and strongly considering an aquamaxx denitrator.
The only thing holding me back is the bad reputation (the why don't more people use them that's been discussed in this thread) and H2S concerns.

Regarding H2S, how have you dealt with this when the reactor gets out of balance? How bad is the smell and how long does it take to go away? Have there been any studies on what levels of H2S can be produced from a denitrator? In my case, i'll be going with the large TS3 model for a 500gal tank.

Below is some safety information I found on H2S:
Exposure to lower concentrations can result in eye irritation, a sore throat and cough, nausea, shortness of breath, and fluid in the lungs(pulmonary edema).[25] These effects are believed to be due to the fact that hydrogen sulfide combines with alkali present in moist surface tissues to form sodium sulfide, a caustic.[30] These symptoms usually go away in a few weeks.

Long-term, low-level exposure may result in fatigue, loss of appetite, headaches, irritability, poor memory, and dizziness. Chronic exposure to low level H
2S (around 2 ppm) has been implicated in increased miscarriage and reproductive health issues among Russian and Finnish wood pulp workers,[31] but the reports have not (as of circa 1995) been replicated.

Short-term, high-level exposure can induce immediate collapse, with loss of breathing and a high probability of death. If death does not occur, high exposure to hydrogen sulfide can lead to cortical pseudolaminar necrosis, degeneration of the basal ganglia and cerebral edema.[25] Although respiratory paralysis may be immediate, it can also be delayed up to 72 hours.[32]

• 0.00047 ppm or 0.47 ppb is the odor threshold, the point at which 50% of a human panel can detect the presence of an odor without being able to identify it.[33]
• 10 ppm is the OSHA permissible exposure limit (PEL) (8 hour time-weighted average).[16]
• 10–20 ppm is the borderline concentration for eye irritation.
• 20 ppm is the acceptable ceiling concentration established by OSHA.[16]
• 50 ppm is the acceptable maximum peak above the ceiling concentration for an 8-hour shift, with a maximum duration of 10 minutes.[16]
• 50–100 ppm leads to eye damage.
• At 100–150 ppm the olfactory nerve is paralyzed after a few inhalations, and the sense of smell disappears, often together with awareness of danger.[34][35]
• 320–530 ppm leads to pulmonary edemawith the possibility of death.[25]
• 530–1000 ppm causes strong stimulation of the central nervous system and rapid breathing, leading to loss of breathing.
• 800 ppm is the lethal concentration for 50% of humans for 5 minutes' exposure (LC50).
• Concentrations over 1000 ppm cause immediate collapse with loss of breathing, even after inhalation of a single breath.

From my understanding the hydrogen sulfide is really only produced if the water becomes completely stagnant for a while so if water continues through the denitrator you should be okay but the smell is really pungent compared to the toxicity. I think the only time this would be an issue would be if the power fails then I would just pump the water through the denitrator into a bucket and discard.

 

[lawise]

Yes, exactly, just increase the flow. Mine is running as a steady stream now that it has cycled.

 

[lawise]

From my understanding the hydrogen sulfide is really only produced if the water becomes completely stagnant for a while so if water continues through the denitrator you should be okay but the smell is really pungent compared to the toxicity. I think the only time this would be an issue would be if the power fails then I would just pump the water through the denitrator into a bucket and discard.

You also have to remember a human can sense the rotten egg smell at .0005 PPM. To get up to 2 or 5 ppm's would be an awful lot, it would probably drive you out of the house.

 

[Greaps]

Great Info thanks for sharing. Curious how are you controlling phosphates?

 

[lawise]

Great Info thanks for sharing. Curious how are you controlling phosphates?

My phosphates have been very low .1 so far, haven't had to do anything yet!

 

[LobsterOfJustice]

Great Info thanks for sharing. Curious how are you controlling phosphates?

GFO

 

[Donovan Joannes]

My denitrator takes care PO4 as well

 

[lawise]

My denitrator takes care PO4 as well

Cool, maybe mine will as well !

 

[Donovan Joannes]

Cool, maybe mine will as well !

Slowly but surely. Certain bacteria strain will consume PO4 more but if I am not mistaken almost all consume PO4 along side NO3 at certain ratio.

 

[Greaps]

Do you feel the need to run a skimmer with this setup?
Do you get bacterial blooms outside the reactor?

 

[Randy Holmes-Farley]

FWIW, I discuss hydrogen sulfide in the aquarium in extensive detail here:

Hydrogen Sulfide and the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2005-12/rhf/index.php

When dissolved in water, the smell depends strongly on pH (which determines how much is in the volatile, hence "smellable," H2S form). Humans often can just detect hydrogen sulfide odors when the concentration is above about 0.029 ppb in freshwater. In seawater at pH 8.2, where only 6% of the sulfide present is in H2S, this odor threshold is likely higher, perhaps on the order of 20-fold higher (0.6 ppb). Fortunately, that threshold is below the lethal limit of many aquatic organisms (usually above 5 ppb; sometimes as high as 50,000 ppb), so odor often can be detected by humans before hydrogen sulfide rises to acute, lethal concentrations in reef aquaria.

That said, the sulfur in a sulfur denitrator is not likely going to become hydrogen sulfide. It is the sulfate in seawater that more typically becomes hydrogen sulfide when there are organics decaying in anaerobic seawater.

One concern is this method depletes alkalinity relative to calcium, so folks may need to monitor alkalinity when using it.



Here's my general commentary on sulfur denitrators and other nitrate reduction methods:

Nitrate in the Reef Aquarium - REEFEDITION
https://www.reef2reef.com/blog/nitrate-in-the-reef-aquarium

Sulfur Denitrators

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

2 H2O + 5 S + 6 NO3– → 3 N2 + 5 SO42- + 4 H+

The production of acid (H+) in this reactor can tend to reduce the aquarium alkalinity. 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+ → Ca2+ + 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 Ca2+ per week. Since calcium weighs 40 mg/mmol, that’s 4.3 ppm Ca2+ 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. Additionally, the acid produced will have a long term lowering effect on the alkalinity. In fact, it is double dipping on the alkalinity depletion since alkalinity is consumed when the nitrate is produced, and again when it is removed in the denitrator. So if you use a sulfur denitrator, be sure to monitor the alkalinity in the aquarium.

 

[Randy Holmes-Farley]

Do you feel the need to run a skimmer with this setup?
Do you get bacterial blooms outside the reactor?

There would be no reason to expect it to drive bacterial growth away from the sulfur particles (or perhaps not even on them in aerobic seawater, like sitting on the bottom of a sump).

 

[Randy Holmes-Farley]

Slowly but surely. Certain bacteria strain will consume PO4 more but if I am not mistaken almost all consume PO4 along side NO3 at certain ratio.

Just like organic carbon dosing driving denitrification and hence relatively less phosphate uptake, this method is greatly skewed to nitrate removal because the nitrate is used both as a source of oxygen to oxidize the sulfur, and as a source of N for tissue growth.

So you may need a phosphate removal method such as GFO to accompany a denitrator.

 

[Donovan Joannes]

Just like organic carbon dosing driving denitrification and hence relatively less phosphate uptake, this method is greatly skewed to nitrate removal because the nitrate is used both as a source of oxygen to oxidize the sulfur, and as a source of N for tissue growth.

So you may need a phosphate removal method such as GFO to accompany a denitrator.

I haven't test my PO4 for more than 10 months. The last test register less than 0.1 (sera). I can't afford for digital tester, but so far my corals are growing with good coloration. I never register PO4 higher than 0.1 since May last year.

 

[Randy Holmes-Farley]

I haven't test my PO4 for more than 10 months. The last test register less than 0.1 (sera). I can't afford for digital tester, but so far my corals are growing with good coloration. I never register PO4 higher than 0.1 since May last year.

This tank has phosphate of 1.24 ppm, so yours may be higher than you think. lol

https://reefs.com/magazine/skeptical-reefkeeping-ix-test-kits-chasing-numbers-and-phosphate/

 

[Donovan Joannes]

This tank has phosphate of 1.24 ppm, so yours may be higher than you think. lol

https://reefs.com/magazine/skeptical-reefkeeping-ix-test-kits-chasing-numbers-and-phosphate/

Just tested and it's 0.5mg/l

 

[lawise]

Do you feel the need to run a skimmer with this setup?
Do you get bacterial blooms outside the reactor?

The directions say you do not need a skimmer but I do use a protein skimmer I did not see any bacterial blooms outside of the reactor yet, but mine has only been set up for a couple of weeks