Sulfur Media, must it run in a reactor?

[Crabb]

I have a 55gal with a 15gal sump. The tank is about a year old now. My question is: If I used CaribSea LSM media, with their ARM media, in a PVC tube placed in the back filter area (just before the overflow), independent of anything and everything else, would it simply mimic a deep sand bed? Would it act as a safe harbor for some anerobic bacteria, eating nitrate (albeit at a slow rate)? I envision 3 possibly, open at the top to allow escape of gases, in the back of the aqurium where water slowly moves toward the overflows and down to the sump. I figure some flow will be needed, but no pumps! Placement should allow for some exchange to occur, but it would be a movement of water that would be really slow.

What do you guys think? Anybody here used sulfur media in such a way? I know most want control with reactors, but I've heard of sulfur catastrophes that make me wary of putting sulfur in a cannister that could plug or explode. Or otherwise create a problem.

Is a DSB bucket with some LSM at the bottom a good idea? Anyone with experience please reply... Thanks!

 

[Randy Holmes-Farley]

If you can control the oxygen in the entire area to be below normal, then yes it might work. But it cannot just be open to the bulk water. If any of it is highly oxygenated, it will oxidize quickly from the outside, converting all the sulfur to sulfate and not performing the way it is supposed to. That might work sort of like biopellets, but it could raise sulfate reasonably rapidly, I expect.

 

[AcroporAddict]

Short answer to your question is yes, it needs to be run in a reactor.

Like Randy said, you need to control the oxygen going to the sulfur if you are going to grow anaerobic bacteria on the sulfur media itself, and that means a very slow drip rate, which provides an anoxic environment for the sulfur media. A typical sulfur denitrator is just like a calcium reactor, but without the CO2 inlet, with just an inlet in for water and an out line for effluent, and a recirculation pump. The recirculation pump keeps everything evenly distributed in the reactor. For most tank setups, you will use a final drip rate of between 3-6 drops per second in a mature denitrator. While the denitrator is cycling, you will have a much slower drip rate, then as the bacteria colony in the reactor grows, you can slowly increase the effluent drip rate. You cannot have a high flow rate through the reactor because too much oxygen in the water inhibits the growth of the nitrate consuming bacteria.

Ultimately, when your denitrator is mature and the denitrator effluent is reading 0 nitrates, you can push the flow rate up as long as the effluent coming out of the denitrator has 0 nitrates in it. After your reactor is cycled, if your effluent is showing any nitrates at all, you need to reduce the effluent rate back until the effluent nitrate level goes back to zero.

Ideally, you want the amount of nitrate consumed in 24 hours by the reactor to equal the amount produced by the reef in 24 hours, this being after the denitrator has lowered the tank level to the point you want, whether that be 0 or whatever.

So all of the above really dictates a closed reactor cut off from room air with a very slow flow rate.

There are some very porous biomedia available that claim to reduce nitrates because they are supposed to have low oxygen areas inside their structure that are applicable to an open type media holding arrangement with no real flow requirements, like SeacChem Matrix or other brands of the same type media.

You can easily make a DIY sulfur denitrator, or there are commercial units available. I use a Midwest Aquatic Denitrator, which is basically a knockoff of the Korralin denitrator.

The sulfur media usually goes on the bottom half of the reactor, with the calcareous media in the top half. The calcareous media is there to raise the pH of the effluent some, as the typical sulfur denitrator effluent pH is much lower than that of a calcium reactor.

Below is a Midwest Aquatic denitrator with a typical media arrangement.

 

[Crabb]

Thanks for the quick response. Both answers were exactly what I was looking for. Thanks. As always it seems to be about control, something I was hoping to avoid. Lol. Sometimes I feel nature does it best, I was only wanting to help it along a bit. Bit I can see I would probably end up helping it along too fast, like runaway train fast. Oh well. My nitrates aren't crazy high, I'm trying to get them below 10ppm but it seems like an uphill battle. If you have any specific suggestions I'm all ears. I know I'm not phosphate limited (I thought so for awhile) because I'm still growing microalgae. I do my water changes, alk and cal are steady as a rock at 10dkh and 420ppm respectively (I have a doser), and phosphates reading zero (occasionally 0.25). All the LPS and softies are doing good, except for the zoanthids, I've never been able to make them very happy. I am running GFO and carbon in a dual reactor. Thought about turning sump into a fuge, but I'm definitely gonna need a bigger cabinet for that. Any suggestions as to the macro? And I'd need a new diamond ring... cause that's the only way my wife will be happy watching a new fish investment going in. Lol.

 

[Randy Holmes-Farley]

Organic carbon dosing is a fine plan for elevated nitrate.

 

[Crabb]

Already tried that, the vodka ended up giving me a pretty good red cyano outbreak. It's gone now (in a relative sense), but I wasn't sure if I should try the vinegar or not. You need 8x the vodka dose in vinegar correct? And wouldn't adding an acid cause problems with alkalinity? I was up to 4mL a day with vodka. Nitrates definitely came down, but like I said I had to stop cause of the cyano taking over... And would the same anaerobic bacteria strains feed on the vinegar as the vodka? Just curious.

I've also considered biopellets. If I started biopellets the bacteria are heterotrophic, so if oxygen is ok for them why is flow such a big issue? Because it seems of what I've read that it's similar to a sulfur denitrator as far as flow control, and I really don't know why. If I'm giving them everything they need to be happy, why is how fast I'm giving it to them an issue? Other than if they stripped my water of everything good, (in which case I'd fix it fast!) I don't see a down side to flow...I mean I know they gotta get knocked off the carbon for the skimmer to pick up but trying to wrap my brain around that one...

Btw, Randy I just wanted to say I've read a few of your articles. Wow. Thank you so much for the insight into this stuff. I can see there's way more to it than I ever thought, but I find it really interesting. At this point I have enough to read and study for a couple of years, so bear with me while I try to catch up to the status of "newbie". Lol.

 

[Randy Holmes-Farley]

Yes, folks using vinegar (such as myself) dose a lot more than folks dosing vodka.

Vinegar or pellets are fine choices.

Sorry, I have to get to work and can't answer the why on flow with pellets just now.

 

[Randy Holmes-Farley]

Flow is an issue for polymer pellets just so you do not blast all the bacteria off the pellet surface or grind them off as the pellets move around.

You are not trying to induce low oxygen around them (unless this is in a carbon denitrator, which if it is, that's the same type of situation as the sulfur denitrator).

Different bacteria likely consume vodka and vinegar, although we don't know for sure in reefs. Probably both anaerobic and aerobic, and even some larger organisms (even corals).

Vinegar does not impact alkalinity long term. Once it is consumed, there is no impact. In the meantime there may be a slight decrease in measured alk, and that might even happen with vodka if acetic acid is made as an intermediate.

Adding 100 mL vinegar to a 100 gallon system will only drop alk temporarily by 0.23 meq/L (0.6 dKH). If that concerns you, you can dose vinegar saturated in calcium hydroxide. I did that for quite a while, but no longer bother. That method will actually boost calcium and alk a bit.

Note, however, that this temporary change in "alkalinity" from dosing vinegar does not come with a reduction in bicarbonate. It is due to a pH lowering which converts carbonate into bicarbonate. So if corals are taking up bicarbonate, they see no decrease in available bicarbonate, and might actually see a slight increase.

 

[Crabb]

Thank you for all the suggestions. I'm glad I didn't go through with my idea now.

As for the vinegar and kalk, that piques my interest and I may try that, but the biopellets I think are my first choice for long term denitrification. I will no doubt try one of the reactors that was mentioned above.

Thanks one and all for your comments and help, and chemistry!:hmm5:

 

[Randy Holmes-Farley]

You're welcome.

Good luck.

 

[mmotown]

Guys I have a quick question. I am putting my koralin 1502 back into service. I need a feed pump to feed the reactor. What can I use?