Detritus in a reef tank

[Scott Campbell]

Did a few calculations for a cube. The ratio of tank volume to bottom surface area increases with increasing volume. That is, as the tank size increases, the amount of water increases faster than the bottom surface area. For a fixed substrate depth, that means the amount of water grows faster with increasing tank size than the total amount of detritus in the system found in the substrate. On a tank wide basis, detritus is more “dilute”.

As for the rest the detritus debate...

But it is not really that simple. I don't use a substrate in my tank - just lots and lots of rock. Bigger tank, more rocks, more area for detritus to supposedly settle. And most large tanks are not cube shaped. Many are quite long and relatively shallow. Some folks keep very minimalist tanks regardless of size. Some folks cram everything they can in the tank regardless of size. That said - you make an interesting point.

In my opinion, using a vague and rather false notion of "large tank dilution" to explain away and dismiss every successful tank that does not engage in manual detritus removal is counter-productive and just plain misleading. If people are struggling with their tanks and someone wants to recommend breaking down the tank, siphoning out everything possible and starting anew as one option - more power to them. But to insist (over and over and over) that no other methodology can really be successful and if it appears you are successful, then it is only because "dilution" is masking the problem - that is rubbish.

 

[Scott Campbell]

One point ive thought about is what effect does detritus have on yellowing water. And how does yellow water effect light penetration.

My other concern is what kind of parasites or bacteria thrive in a heavy detritus environment compared to light detritus environment.

Opting not to manually remove detritus does not necessarily create a "heavy detritus environment". It certainly might if you have poor export relative to import or no in-tank means of breaking down the detritus - but I don't think anyone is really arguing for excessive amounts of detritus. I'm not. There may indeed be bad consequences associated with high levels of detritus. I am simply pointing out that manual removal is not the only option for dealing with detritus. In 30+ years I have never once removed detritus from my tank. I also have no visible detritus. Because I have a tank full of organisms that consume detritus.

 

[KTTX]

Opting not to manually remove detritus does not necessarily create a "heavy detritus environment". It certainly might if you have poor export relative to import or no in-tank means of breaking down the detritus - but I don't think anyone is really arguing for excessive amounts of detritus. I'm not. There may indeed be bad consequences associated with high levels of detritus. I am simply pointing out that manual removal is not the only option for dealing with detritus. In 30+ years I have never once removed detritus from my tank. I also have no visible detritus. Because I have a tank full of organisms that consume detritus.

What in tank measures and organisms you use to combat detritus?

 

[Dan_P]

But it is not really that simple. I don't use a substrate in my tank - just lots and lots of rock. Bigger tank, more rocks, more area for detritus to supposedly settle. And most large tanks are not cube shaped. Many are quite long and relatively shallow. Some folks keep very minimalist tanks regardless of size. Some folks cram everything they can in the tank regardless of size. That said - you make an interesting point.

In my opinion, using a vague and rather false notion of "large tank dilution" to explain away and dismiss every successful tank that does not engage in manual detritus removal is counter-productive and just plain misleading. If people are struggling with their tanks and someone wants to recommend breaking down the tank, siphoning out everything possible and starting anew as one option - more power to them. But to insist (over and over and over) that no other methodology can really be successful and if it appears you are successful, then it is only because "dilution" is masking the problem - that is rubbish.

I haven’t read the posts that explain away the success of large systems as a dilution effect.

 

[brandon429]

those are assumptions Ive been making not from measuring or math but just the simple 90s technique of set up a hands off reef (all detritus in the bed stays in the bed, not phys removed) among varying system sizes and seeing which ones last the longest before eutrophication manifests. Along with many online feedback posts from messages/work threads its my opinion large tankers are spoiled rotten regarding waste management and when we tried to implement their strict, strict no access rules in tiny systems, they didn't last long.

so the progression then became keeping the tiny systems clean by force, seeing what happens when thousands of pico reefers do this in sync then feed it back in forum updates, having way less invasions than nearly all large tanks, and nothing bad predicted by tank full access panning out but rather the opposite; very extended lifespan in systems that are metabolically 10x faster than a large tank (another gross subjective measure)

what I mean by faster is they'll show the signs of eutrophication/losses/invasion solely by leaving the detritus to compile even if you're doing water changes.

I know Scott above isn't advocating poor export. Am merely remarking on the cost/weight/ecological impact of detritus in tanks large to small, these are the patterns I'm relaying after a very long time of pattern watching others systems.

 

[brandon429]

El Fab's Simple Guide to Pico Tanks

El Fab's Simple Guide to Pico Tanks More and more people are venturing into the realm of pico reefs and I've noticed that a lot of the same questions are frequently tossed around, so I decided to create this thread to offer some basic insights to help get everyone started. Whether you're a beginn...

www.nano-reef.com

Ive linked that example thread before in a diff place but its fitting here. Detritus killed his system via cyano invasion (still rampant in todays reefs, we're working to get people to clean efficiently need more time ha)


that above represents the exact manner we've all been advised to set up a reef, but he did it in 3 gallons.

If that would have been a 150, scaled up, we'd still be alive/running yet he'd be dosing nopox daily, dealing with N and P Imbalances, setting up ATS, setting up reactors, buying UV, from all the pent up waste in the refugium + display sandbed fish diaper.

*opinions vary on causatives in every thread* just stating my pattern observation: the wastes leaking from up under into the tiny 2 gallon ish water column could no longer be balanced/uptaken by the plants in the refugium, so total invasion took over. we have pico reefs still running from when this one was made, and since they're cleaner, they're alive. half his volume as well...

since it was a 3 gallon, it lasted 3 years/faster metabolism analogy. pico reefs speed up the ends so we don't have to wait so long to evaluate a different method or a change in method.

His sps was magazine-pic quality and blog-review best in show for that timeframe, but the system was a bell curve design due to storage issues, in my opinion. we took the bell curve and straightened it solely by ridding the system of waste occasionally like the high energy/evacuative fringing reef area

 

[Scott Campbell]

What in tank measures and organisms you use to combat detritus?

You need a variety of small organisms of differing sizes so that the detritus can be broken down completely. I personally have very large quantities of worms (bristle worms, flat worms, etc.), lots of mysid shrimp, copepods, amphipods, hermit crabs, various sized shrimp and such. The worms and mysid shrimp populations are self-sustaining. I supplement the amphipods about once a year. (Aquarium Depot seems to have the best.) I also culture my own copepods in glass gallon jugs and supplement every couple of weeks. It may not be necessary to supplement the amphipods and copepods but it seems more effective to maintain numbers in excess of what can be supported by existing detritus. And they get eaten any way.

Maintaining detritus feeding populations works the same, in principle, as algae turf scrubbers and carbon dosing. You are using living organisms to bind up excess nutrients. The process works well with a couple of caveats:
1) Substrates can be problematic. The detritus needs to be accessible. I have a mostly bare bottom tank with a small patch of substrate for my wrasse.
2) The process is much slower than something like carbon dosing. It takes time for the detritus to be consumed.
3) The organisms have to be maintained in large populations relative to the number of fish you have. Takes a lot of small bugs to process the waste of one fish. So you can't keep a ton of fish if you want to avoid excess build-up of detritus.
4) The organisms are not directly harvested like macroalgae or bacteria pulled out by a skimmer. I do occasionally harvest out bristle worms - but I can't really say that is a sane thing to do. Instead the detritus feeding populations need to be consumed as food by your fish. So you need fish that eat worms and amphipods. Which not all fish do. I have a Melanurus Wrasse which completely decimates the bristle worm and flat worms in my main tank. And I have a Purple Dottyback who does the same. The Dottyback never touches any supplemental food I add. The fish only eats the worms and amphipods living in the tank. So choice of fish can be limited if you want to be all in on this process.
5) The organisms need a decent amount of real estate to survive and thrive. So that means a lot of rock in the tank. Again - not always something people want to do. My tank is a mass of rock.
6) You really need a refugium to make this work. My refugium is overrun with every imaginable critter - pests included. Choice of fish is critical in making sure these organisms do not overrun your main tank. But you need a safe haven to keep the populations sustainable.

The advantages for me:
1) My tank is old and completely overtaken by coral. I have no ability to siphon out detritus. I would just end up smashing a lot of coral. So this process works extremely well for my tank.
2) My fish don't need any supplemental food. I still give them supplemental food just because it is fun for me. But they would be largely fine surviving on the organisms and algae in the tank. Which means I don't have to add much food to the tank which greatly reduces the export demands on the tank.
3) My fish seem happier and healthier grazing on live food throughout the day.
4) I really like all the small shrimp and starfish and worms. They are often as interesting to me as the fish and corals.

Disadvantages:
1) Need a lot of surface area (i.e. rocks).
2) Need a refugium
3) Can't stock a lot of fish
4) Choice of fish somewhat limited
5) Need to be worried about substrate limiting access to the detritus
6) Still need a regular export mechanism. Detritus consuming populations simply recycle nutrients. I harvest macroalgae from my refugium and bacteria from a skimmer as my means of export.
7) May need to supplement organisms
8) I do worry about overall bioload during power outages. So I keep generators and air pumps as back-ups.
9) Almost certainly more complicated to implement than simply siphoning out detritus manually.

So obviously not something everyone wants to put in place. Maybe no one else finds it appealing. But as a process it is extremely effective. I certainly have mulm throughout my tank but no apparent detritus after 30+ years. On occasion I do have to mess with my sump or pull out a coral and I have never noticed any resulting "black cloud" that people often describe. I am certainly not "storing" detritus. And it honestly seems safer to let the critters keep the tank clean rather than me crashing around trying vacuum out waste. And the critters are on the job 24/7 while me not so much.

Hope that helps!

Scott

 

[brandon429]

in nearly all of our nano reef/pico reef modeling we never were dosing a whole bunch of pods /building them up that level we just accepted remaining ones as good enough after our cleaning goals. to test that type of out competing organism in high loading might give neat results on small scale models maybe it would lessen work somehow.

 

[Dan_P]

those are assumptions Ive been making not from measuring or math but just the simple 90s technique of set up a hands off reef (all detritus in the bed stays in the bed, not phys removed) among varying system sizes and seeing which ones last the longest before eutrophication manifests. Along with many online feedback posts from messages/work threads its my opinion large tankers are spoiled rotten regarding waste management and when we tried to implement their strict, strict no access rules in tiny systems, they didn't last long.

so the progression then became keeping the tiny systems clean by force, seeing what happens when thousands of pico reefers do this in sync then feed it back in forum updates, having way less invasions than nearly all large tanks, and nothing bad predicted by tank full access panning out but rather the opposite; very extended lifespan in systems that are metabolically 10x faster than a large tank (another gross subjective measure)

what I mean by faster is they'll show the signs of eutrophication/losses/invasion solely by leaving the detritus to compile even if you're doing water changes.

I know Scott above isn't advocating poor export. Am merely remarking on the cost/weight/ecological impact of detritus in tanks large to small, these are the patterns I'm relaying after a very long time of pattern watching others systems.

Does your information and experience indicate that small systems without fish need a substrate deep clean less often than systems with coral only?

 

[brandon429]

Dan

we're used to working without fish in the small setups, Id have to only guess it compounds faster

literal whole pellet fish waste being sinked in the bed + live rock castings and detritus components from the active mini reef daily activity. flow, active fish sifters etc all affect finals but it seems most accurate to say we are either managing detritus in portions or as catch up if we want to age out a true mini model of a large reef to really test the bounds of years + storage + eutrophication + coral health consistency. left untended, they look great for about 3 years, even the one gallon ones and then the bell curve down is sharp, manifests nearly universally as cyano troubles.

nano-reef.com is a 20 yr trove of small reef patterns, they're awesome science patterning there to check any of these items, see how long tanks are being updated in member threads etc/lifespan patterning of quick models. and nearly all use fish, just the picos typically don't as we don't want to be cleaning 2x weekly.

Nano Sapien's old nano isn't taken apart and cleaned, but I think it still passes what we call a drop test (highly disturbed sand in a full reef, how much cloud) in that it would not kill his tank if he performed one. however he's performing DSB maintenance, flow, variables and water change export of dissolved wastes, the sum effect is tank aging pretty rare for that amnt of respiring live rock to gallon ratio. this shows diversity in ways to manage sinking vs our mighty harsh and fast ways.

Most reefs, not able to pass that drop test. There are plenty of aged (and doing fine) reef tanks with DSB that could die from disturbance, breaking the stratifications and oxygen and acid and sulfide zones if applic. (various stages of detritus decay are common in hands-off dsbs, I recall your nutrient measures as well or detritus)

I like to say that depending on how we regulate organic storage, that's how wide the options become including invasion takedown for every year added in a typical sandbed system.

the cleaner we reef, the tighter, more converging outcomes, such that if we require a peanut butter jar to produce coral longterm it will nowadays without fail. we have a repeating pattern that works over, and over, and it involves causing fringing reef zone activity more often than we were ever allowed prior

 

[Scott Campbell]

I haven’t read the posts that explain away the success of large systems as a dilution effect.

Lots and lots of posts / threads that say this repeatedly:

People who keep large tanks have it easy, they have dilution to offset all the stored up waste.

It is a meaningless statement. A large tank could be slammed with fish generating waste proportionately far faster than a lightly stocked smaller tank. "Dilution" and unspecified "offsets" are terms Brandon throws out whenever someone describes a successful and long-term set up that does not involve manual detritus removal.

 

[brandon429]

I agree to that impact but the tendency is as stated. Among a hundred samples, these patterns emerge that’s all. People are scaling their bioload for tank size such that it’s more predictable than you’re giving credit for, we have thousands of pico reefs who never get dinos, no current examples across forums I’d venture to say. No small pico reefs get cyano challenges I know of, post current ones from any forum. it’s really always large tanks that need detritus management or other methods to become cured of an enduring cyano invasion.

It’s my opinion we were able to turn the tide early for small reef keepers into a cleaner running, detritus removal practice vs the larger tanks of today still by and large storing up...and invasions follow the nutrient sinking strongly in pattern

Nano Sapiens old nano, and Maritza the vase reefs 7 yr sps 1.5 gallon do not evacuate the sandbed they always run with some degree of detritus and they’re going to live a long time, so I’m not against detritus fully. I cannot recall the last time anyone posted for help in the sand rinse thread for an invasion who showed up with balanced detritus loading. Reefing normally, per today’s standards, still results in too much storage and too many invaded tanks

 

[Nano sapiens]

After reading many of these detritus related threads over the years, it is apparent that there is no 'one method fits all' when dealing with detritus.

IMO, the best we can do is come up with general recommendations based on the collective experience of thousands of reef keepers over the decades and thereby deduce what method, or methods, are most likely to lead to success in the long term for the various reef aquarium categories (Pico, Nano, Medium, Large, Extra Large). However, in the final analysis it's up to the reef keeper to gain a deeper understanding of the unique attributes of his/her system and develop a maintenance regime that will help keep the system in balance.

 

[brandon429]

Disturbed sand bed.

I have a 75 gallon fowlr tank that has been up for about 2 years. I have had nothing but trouble with this tank. Long story short i decided to clean tank yesterday. Toothbrush to rock and vacuum out detritus. I stirred up sand a little with the vacuum but worse the circulation pump must have...

www.reef2reef.com

awaiting pics, but I bet he was not crudded up/invaded before the move. The normal, non accumulated condition of any dsb carries this risk, due to in between the grains. we have other threads collected where a rock stack shifted n fell while on vaca/cloud loss and then a powerhead dislodging while gone/clouding loss. This isn't to overplay the evil of detritus or anything, I'm just saying the greater public should have been advised of pure sand control, rinsing options and how they're great not bad, about 20 years ago.

Moved tank without changing sand-- everything is dying!!

So let's just move past the fact that I should've removed all the sand before moving my 90gal tank... but now that everything is dying (corals, anemones, fish, inverts), is there anything I can do?? I've put the three living fish (removed one that died) in a hospital tank (also uncycled, but...

www.reef2reef.com

 

[chipchipbro]

Now after all the posts..
Do I need to siphon out detritus in my sump or not?
I can see alot of detritus in my sump and was wondering if I need to clean that stuff.

What is your way to clean it? My idea was to siphon it out into a filter sock and let the water flow back into the sump.
maybe this is a no-go i dont know.

 

[Randy Holmes-Farley Verified Community Expert]

Now after all the posts..
Do I need to siphon out detritus in my sump or not?
I can see alot of detritus in my sump and was wondering if I need to clean that stuff.

What is your way to clean it? My idea was to siphon it out into a filter sock and let the water flow back into the sump.
maybe this is a no-go i dont know.

I never did. So the answer to "do I need to" is clearly no it at least some cases.

The answer to whether it may be a benefit or detriment or neutral to your tank is unclear, but more folks remove it than don't.

If you do not have elevated nitrate or phosphate, i cannot think of a reason to remove it.

 

[chipchipbro]

I never did. So the answer to "do I need to" is clearly no it at least some cases.

The answer to whether it may be a benefit or detriment or neutral to your tank is unclear, but more folks remove it than don't.

If you do not have elevated nitrate or phosphate, i cannot think of a reason to remove it.

Well, I do have always a bit higher No3 and Po4 and right now I am dosing carbon.
I thought maybe if I remove the detritus I might be able so slowly stop dosing carbon (if the problem is the detritus)

 

[Randy Holmes-Farley Verified Community Expert]

Well, I do have always a bit higher No3 and Po4 and right now I am dosing carbon.
I thought maybe if I remove the detritus I might be able so slowly stop dosing carbon (if the problem is the detritus)

That's possibly true. That may or may not be net beneficial to the tank, but if you want to possibly stop dosing, it's a fine thing to try.

 

[GARRIGA]

Haven’t remove poop since first setting up my tank in September 21 minus the very infrequent brine shrimp net passes when there’s too much stuff floating and I can count on one hand how many times I’ve done that.

Fish only for the most part because I’m testing decomposition in a closed system for a future build where minimal maintenance the goal and requirement. No ammonia. No nitrites. Nitrates can be bottomed out with NoPox which also tends to keep my phosphates under 0.25 ppm which for my current needs is fine. No GHA, either.

At least for me. Detritus hasn’t caused these parameters to get out of control. If only I could proliferate bio digesters then perhaps my holly grail of converting mulm through mineralization back to calcium and other components the inhabitants can use and complete the cycle as nature does.

Not a scientist. Just messing with water based on what I’ve read and my interpretation.

Perhaps instead of weighting unprocessed detritus then why not form a way to capture and decompose it then weight the resulting mulm? I’d be curious as to how large that is as well. Plan is to only service the mulm by extracting that with a micron fikter of appropriate size since figuring out how to solve for that final component has become futile.

BTW, I’ve noticed that detritus in the display doesn’t appear to get processed because there’s way more than I’d expect yet my parameters aren’t toxic therefore what something must be processed and I’m guessing that which is trapped in the gravel perhaps. I’ll post a pick of how things look this morning for comparison.

 

[GARRIGA]

Before and after pics. Goes to show that in my little pie of the ocean that lingering detritus in the display isn’t contributing to high nutrients as far as ammonia, nitrites, nitrates and phosphates. One of these days I’ll send that ICP in and see what else going on. Suspect low itin since I can’t grow GHA but red turf has established. First for me. I find it aesthetically pleasing plus it help solve nutrients as well.

My aestrea is either spawning or dying. Caught on video, too. Lucky timing I guess.