Does my decade old sand bed actually nitrify? Who eats Ammonia in our tanks?

Aqua Man

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But if you pressed me right now to come up with something chemically biologically necessary to a reef tank that happens in my sandbed... I'd have to think a long time.
Sand bed is reportedly needed for ph buffering.
 
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Dan_P

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I had a silica playsand dsb, no buffering, for years.
Could you say whether the amount of the fluffy detritus that typically collects in a sump was different with play sand?
 

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Could you say whether the amount of the fluffy detritus that typically collects in a sump was different with play sand?
I had 1/4 inch of crud in the sump with countless bristleworms. For what it’s worth, I never saw anything on the sand that looked to be bacterial in nature. There was a little activity evidenced by gas bubbles about an inch under the surface, and worm holes but apart from that it looked strangely dead. I’m guessing the small particle size prevented detritus entering the bed as when I removed this bed it was totally clean, no crud, nowt. This was a Kalkwasser replenished system.

56E2BFCD-8760-4315-B439-1B468691099D.jpeg
 
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Garf

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Found a sand bed pic, apologies for the poor quality, it was a while ago;

 

elysics

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How does this mesh with peoples experiences with how sandless tanks are so much harder to get running? Is that all just placebo and misattribution?

Could the process of taking the sand from the tank and putting it in a test vessel actually kill or shock the microbiome in there?
 
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brandon429

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I think those are easy to get running vs hard to get running. Also there’s less liability in a bare bottom tanks, sandbeds stratify wastes into zones that can affect reefs we think (in sand pattern work threads) while bare bottom tanks just have common aerated detritus sitting about, if you mix it up nothing happens.

they’re easy to get going if we use transferred live rock, that is :)


all dry rocks, no sand, most sterile reef = dinos by 3 pm today
 
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Randy Holmes-Farley

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Sand bed is reportedly needed for ph buffering.

That's never made sense, if by pH buffering you literally mean keeping the pH up.

Yes, aragonite sand will slowly dissolve down inside of it where the pH may be very low, but it cannot dissolve at pH of 7.8 and up in seawater, so it cannot help maintain pH 7.8 or higher.
 
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taricha

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Boy,
How disapointing.
All this home brewed science whittled down to... sand is worthless. ;)
I know you're being flip, but just to be clear...
My data is only about sand nitrification, and so far it says that in some tanks sand nitrification is a very small part ( < 10% ) of the ammonia processing of the system.

There could be systems that have high sand nitrification, or maybe not. Maybe something else always steps up to process the bulk of the ammonia. It's worth thinking about what actually has high contact / high flow rate with the ammonia that's mostly in the water. (Coral polyps, algae, film on high rocks, filter pads, socks etc, sand not usually so much).

How does this mesh with peoples experiences with how sandless tanks are so much harder to get running? Is that all just placebo and misattribution?
I've heard the BRS guys say that bare bottom seems to have a more extended and annoying nuisance phase than sandbed. I haven't messed with BB systems enough to know.
But IF it's true, and IF sandbed nitrification is generally low, then that might point to the fact there's a lot of microbial activity that isn't nitrifiers. Microbiome maturity might be a lot more complex than just ammonia processing.

Could the process of taking the sand from the tank and putting it in a test vessel actually kill or shock the microbiome in there?
I don't think so, but it bugs me a little. I'll feel better about this after I make some super juiced up nitrifier sand and can measure actual rapid nitrification rates with the same protocol.

Saw this today - on topic:
Bacteria in Lab.jpeg
 

Paul B

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99.9% of this thread is over my pay grade and I can't test my pH as I have not had a kit in many years but my nitrate is about 5.

As to nitrification ebbing over time, my dolomite gravel has been in my tank over 50 years and has never been changed. I did add some to it about 40 years ago but the rest is the same. It doesn't seem to have gotten smaller, by eye anyway and I have a fairly high fish load. But I do run a reverse undergravel filter so I get circulation through the entire thing.
 

Jon_W79

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I know you're being flip, but just to be clear...
My data is only about sand nitrification, and so far it says that in some tanks sand nitrification is a very small part ( < 10% ) of the ammonia processing of the system.

There could be systems that have high sand nitrification, or maybe not. Maybe something else always steps up to process the bulk of the ammonia. It's worth thinking about what actually has high contact / high flow rate with the ammonia that's mostly in the water. (Coral polyps, algae, film on high rocks, filter pads, socks etc, sand not usually so much).


I've heard the BRS guys say that bare bottom seems to have a more extended and annoying nuisance phase than sandbed. I haven't messed with BB systems enough to know.
But IF it's true, and IF sandbed nitrification is generally low, then that might point to the fact there's a lot of microbial activity that isn't nitrifiers. Microbiome maturity might be a lot more complex than just ammonia processing.


I don't think so, but it bugs me a little. I'll feel better about this after I make some super juiced up nitrifier sand and can measure actual rapid nitrification rates with the same protocol.

Saw this today - on topic:
Bacteria in Lab.jpeg
I think that reason that a lot of people believe that a tank with sand matures a lot faster than a bare bottom tank may be because the sand will probably generally cause a lot more detritus buildup in the aquarium. I would guess that this would generally cause a lot more fulvic/humic acid available in the aquarium. I believe this could possibly help a tank "mature" faster because there may be a very significant number of bacteria and algae that really benefit and/or require humic substances. One example may be my sulfur denitrator, I have read that the bacteria that is most commonly believed to grow in it may require humic substances to be able to grow.
 
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Aqua Man

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That's never made sense, if by pH buffering you literally mean keeping the pH up.
Yes, I was told I HAD to have a sand bed when I started reefing years ago. Now that I’ve learned a few things, Thanks to you, Taricha and a couple others. I don’t believe it anymore.

Also, my tank Is now BB after I realized that it’s for cosmetic purposes only. IMO
 
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taricha

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so, is there anything on this label that is actually true?!! Lol!!
It's almost comical how the statements are potentially-true but mostly not.

1-2" Deep in my sandbed, those things are actually true!
I've buried pellets of NaNO3 and measured that the porewater in the sandbed near the pellets produced nitrite 10x higher than the sand elsewhere. NO3 was being denitrified (I did not detect any ammonia so no DNRA detected)
The pH in my sandbed where organic matter breaks down is ~7.6, if I add more organic matter, it stays ~7.6 because the aragonite in the bed buffers it, and prevents it from being lowered further. (Nitrification of ammonia also lowers pH - I've used phenol red as a pH indicator to detect it, if there's no aragonite around to buffer.)
The low pH conditions (~7.6) that aragonite can buffer, also result in aragonite dissolving and therefore increasing alk.
This also happens in the guts of a sand sifting cucumber - so it's true there too :)
There are also trace elements in the coral skeleton that get released when the coral rubble gets dissolved under low pH.

So all those things happen if you go down far enough in a sand bed, but none of them will happen in the bulk tank water for a reef system where pH and O2 aren't disastrously low.

(I suppose denitrification in a sandbed could be important in some systems. I don't know.)

But yes, we should rinse like it says on the bag :)
 

Joe Rice

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But I do run a reverse undergravel filter so I get circulation through the entire thing.
So "uneaten food and waste" in a sandbed is small - but it still exists. Algae as well as pods, worms and various other sandbed microfauna eat and are eaten and die in the sandbed.
So if my sandbed is largely absent of nitrifiers, then the ammonia generated there would just hang around until some "algae" (cyano, diatoms, dinos, gha etc) fills the niche. It's not like my corals can come down and get it, or would start new colonies in the sand.

As I was reading through this thread I thought about @Paul B and his reverse undergravel filter. Perhaps running an undergravel filter in reverse pushes the ammonia out of the sandbed and into the water column, making it available to the corals.
 

Paul B

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As I was reading through this thread I thought about @Paul B and his reverse undergravel filter. Perhaps running an undergravel filter in reverse pushes the ammonia out of the sandbed and into the water column, making it available to the corals.
I doubt it, but I have no idea. :cool:
 
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WHAT WATER CHANGE "PERCENTAGE" MAKES IT WORTH DOING?

  • 5% - 10%

    Votes: 69 9.3%
  • 10% - 20%

    Votes: 381 51.5%
  • 20% - 30%

    Votes: 179 24.2%
  • 30% - 40%

    Votes: 24 3.2%
  • 40% - 50%

    Votes: 15 2.0%
  • 50% or more

    Votes: 8 1.1%
  • No water change is worth it

    Votes: 29 3.9%
  • Not sure

    Votes: 12 1.6%
  • Other (please explain in the thread)

    Votes: 23 3.1%
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