How to get more denitrification in my tank?

[Miami Reef]

What am I missing in my tank doesn’t seem to have any nitrate export without carbon dosing?


My tank is bare bottom, but I have a decent amount of rock. Shouldn’t that provide anaerobic areas? Why are deep sand beds more synonymous with denitrification?

 

[rishma]

What am I missing in my tank doesn’t seem to have any nitrate export without carbon dosing?


My tank is bare bottom, but I have a decent amount of rock. Shouldn’t that provide anaerobic areas? Why are deep sand beds more synonymous with denitrification? some tanks

I definitely don’t know

I know my nitrate has been higher in some tanks than others. But it’s been really long time since I had a deep sand bed. i suspect not all rock is as good at denitrification. I had a bare bottom that nitrates were really low. At the time I thought it was my very high flow and filtration. Waste didn’t stay in the tank long.

 

[geologeek]

I would say that a sand bed has a larger surface area and is more unified in stratification, so as oxygen is used up in the upper layers the anaerobic processes can happen at depth over a far bigger area.

Your rock will have areas of aerobic bacteria but the pockets if these are not going to be uniform and depends on the porosity if the rock, its pore water pressure, gradients, voiding etc.

 

[Randy Holmes-Farley]

It's never really been demonstrated, IMO, how much, if any, denitrification actually takes place in any given reef tank.

You need:

1. a low O2 place (that is, a place where O2 slowly diffuses in, not fast and not prevented entirely)
2. Nitrate to diffuse in (which is a bit in conflict with #1 since nitrate will diffuse more slowly than O2)
3. Organics to diffuse in (which is similarly in conflict with 1)

So to be honest, I'd expect actual denitrification to be a minor process in most reef tanks

It can be boosted by providing:

1. More organic to drive 3 faster
2. More nitrate to drive 2 faster (but obviously that's counter productive)
3. More regions in #1 to allow all three. All other things equal, twice as much #1 would allow twice as much denitrification

I do agree that sand is much more likely to provide good spaces for #1, and organisms that turn the sand may bring nitrate and organics into low O2 regions (or regions that become low in O2 after the turning) much faster than standard diffusion.

As with many chemistry things in a reef tank, when one digs deeper and deeper into what is actually happening, it is often more complicated than Reefing 101 would suggest.

 

[Sean Clark]

Sulfur Denitrator

 

[Daz_1978]

It's never really been demonstrated, IMO, how much, if any, denitrification actually takes place in any given reef tank.

This!

Back in the day when our sand beds were 4”+ deep, you’d occasionally see a bubble work out… and we just assumed it was maybe nitrogen gas!?!?

I think the best method of exporting Nitrate, is to export it before it becomes Nitrate…

 

[Miami Reef]

It's never really been demonstrated, IMO, how much, if any, denitrification actually takes place in any given reef tank.

You need:

1. a low O2 place (that is, a place where O2 slowly diffuses in, not fast and not prevented entirely)
2. Nitrate to diffuse in (which is a bit in conflict with #1 since nitrate will diffuse more slowly than O2)
3. Organics to diffuse in (which is similarly in conflict with 1)

So to be honest, I'd expect actual denitrification to be a minor process in most reef tanks

It can be boosted by providing:

1. More organic to drive 3 faster
2. More nitrate to drive 2 faster (but obviously that's counter productive)
3. More regions in #1 to allow all three. All other things equal, twice as much #1 would allow twice as much denitrification

I do agree that sand is much more likely to provide good spaces for #1, and organisms that turn the sand may bring nitrate and organics into low O2 regions (or regions that become low in O2 after the turning) much faster than standard diffusion.

As with many chemistry things in a reef tank, when one digs deeper and deeper into what is actually happening, it is often more complicated than Reefing 101 would suggest.

Thank you for this detailed response!

I think the best method of exporting Nitrate, is to export it before it becomes Nitrate…

I have an off topic question about this: Do turf algae (scrubber) and refugiums prefer nitrate or ammonia if they had the choice to use either?

Do they need to work harder to use nitrate?

 

[Randy Holmes-Farley]

I have an off topic question about this: Do turf algae (scrubber) and refugiums prefer nitrate or ammonia if they had the choice to use either?

Do they need to work harder to use nitrate?

Yes to the last question, just like corals, but I've not seen a preference study.

 

[rishma]

I have an off topic question about this: Do turf algae (scrubber) and refugiums prefer nitrate or ammonia if they had the choice to use either?

Do they need to work harder to use nitrate?

Oh that’s interesting. When I read the comment about removal before it becomes nitrate I thought about mechanical filtration. But utilization of ammonia make sense too.

 

[jonelder68]

More macro algae? I seem to have the opposite issue with keeping nitrates on my older tank. It does have a 3-4” deep sand bed as well. But when I let the chaeto get past a certain size from being lazy it will strip the tank very quickly and spots of Dino show up.

 

[sixty_reefer]

Have you considered a maxspect anaerobic block and catalyst?

 

[MBruun]

I have used the "Donovan's Nitrate Destroyer" (aka DND) reactor for the last 17 months.
It works like a charm. When settled in it require only supply of carbon as maintenance. For carbon I use 2 part RO water, 1 part vodka and 1 part vinegar. Seeded with Fauna Marin Bacto Reef Balls

Poor Man's Nutrients Control - Donovan's Nitrate Destroyer

Hello fellow reefers!. I have been in the hobby for more than 3 years, the first 2 years was tough. Cyno, diatom, nuisance algae, high NO3 (120ppm at one time) and ich/velvet. I have tried several nutrient control method (poor man, so most of it were DIY project). GFO, water fall scrubber...

www.reef2reef.com

 

[Dan_P]

What am I missing in my tank doesn’t seem to have any nitrate export without carbon dosing?

How did you come to this conclusion? Maybe the aquarium has a normal dentrification process but is just overstocked.

 

[Miami Reef]

How did you come to this conclusion? Maybe the aquarium has a normal dentrification process but is just overstocked.

Very good point. I thought of that when making this thread. I don’t know for certain.

 

[Reefering1]

Why do you want to stop carbon dosing?

 

[Miami Reef]

Why do you want to stop carbon dosing?

Just to see if there are any changes to the growth and colors of my acros.

 

[rishma]

Just to see if there are any changes to the growth and colors of my acros.

My guess would be carbon dosing adds food and benefits the acros due to increased bacteria in the water, maybe acetate directly useful too.

What would do you think might happen?