Detritus is it as bad as some make out?

[samnaz]

Fascinating article by Dr Shimek, as always.

All to often it seems hobbyists have forgotten or perhaps dont even know of the vast interconnected world hiding within our tanks. For me that’s the most intriguing part.

I haven’t done a water change in months, and I use tap water *gasp* double whammy. Besides changing the floss weekly and vacuuming parts of sand few times yearly... most detritus remains part of the system wherever/whatever that may be or become.

But what do ya know, nearly all my corals survive and thrive, I have a massive microcrustacean population, all kinds of microfauna, and yep... algae. Diatoms galore, some turf algae, some hair algae, coraline, you name it. Yet never had cyano or bryopsis, and I’ve had a single bubble algae in my tank for two years without spreading.

I just let nature do it’s thing. It’s far more brilliant and experienced than I am (or would be if I tried to intervene).

 

[brandon429]

does anyone know if there are links to sandbed studies done in aquaria

Toonen has one online from about 04 but they're scarce in general. something to discern between oceanic and non dilution impacts

 

[Reefin Dude]

SERIOUSLY!!! people are still reading Shimek's stuff!!

i really thought this hobby has finally turned a corner. how many times does his sand bed studies need to be show to be literally full of crap before people will stop reading it and move on to some real information.

argh!! the knowledgable people that were pushed out of this hobby because of him and the other "sand experts" that tried to help the rest of us out is really sickening.

feel free to do some research on where are the "sand experts" now, and how did they get there.

G~

 

[brandon429]

Im convinced it works this way:

the opinion about sandbed technique in general and in essence detritus storage ranges so vastly because each person's tank is at a different stage of imminent eutrophication. even bare bottom ones...easier to remedy but its all waste packed in without dilution if we're reefing in our homes

we cant really have any other conclusion about the matter other than what our current tank and sandbed technique yields. trying to convince someone else on the continuum that their position isn't right doesn't match what they see before their eyes each day, so no buy in.

those with smaller reefs see impacts faster than larger ones, and larger ones foster the diversity better to actually hopefully in the right and luckiest conditions attain true on site mineralization. that's what we all sought, and got a 1% return on. if someone has completed the continuum of tank age and size range and can still come out consuming vs generating nitrates, then that 1% cannot be convinced of any other method. Im sure theres a repeatable way to set up beds/stratifications/plenums/special zones to reliably accomplish bioload reduction vs production.

the masses aren't running beds that way however, so mostly they're advised to export export export if you want have the best chance of being invasion free. luckier less work modes exist too.

*todays availability of pods and worms and live rascals sure might change the game possibly but that all seems like solid waste pellet production even still. really diverse poo. I know of no poopless cucs. it'll have to be some sort of fancy bacterial manip I bet to pull it off in say 20 out of 25 test tanks and sustain that for ex 60 mos. there always has to be a time and dilution factor in any consideration of detritus impact in my opinion. Those two details shape our perspectives drastically, when I read deep on someones idea about bed techniques the first things I look at is how their dilution and tank age or prior tank ages might shape their wview

 

[Reefin Dude]

i am not against substrates. i am against the way people have been told they "work". they are nutrient sinks. nothing more than that. they are not going to make matter disappear. there is not some magic polychaete that creates worm holes into the detrital dimension and makes it all go away. all organisms create waste products, and there needs to be enough resources to support a given population of organisms. any organisms living in a substrate indicate an increase in trophic state of the substrate. the only way nutrients will go away is if we export detritus from the substrate. as long as detritus (nutrients) are exported at a rate that matches the trophic state one wants to emulate, all is good. the bigger the nutrient sink the greater the margin for error.

substrates are nothing but a tool. they can be a very useful tool, but as with any tool it needs to be maintained in order to function at its best.

why are we trying to dilute anything? remove it and be done with the problem. use the substrate to collect nutrients for X amount of time, than replace the substrate and start over. just replacing the tool. restarting the nutrient sink. another X amount of time of easy maintenance. it is all about how you want to spend YOUR maintenance resources.

mineralization is not what we want. the point is to remove the organic material before it has a chance to decompose. letting detritus decompose leads to almost all of the problems we fight as aquarist. low alk (bacteria needing C for decomposition), high inorganic N and P (waste products of organic decomposition), low pH (CO2 is a byproduct of organic decomposition).

G~

 

[Scott Campbell]

i am not against substrates. i am against the way people have been told they "work". they are nutrient sinks. nothing more than that. they are not going to make matter disappear. there is not some magic polychaete that creates worm holes into the detrital dimension and makes it all go away. all organisms create waste products, and there needs to be enough resources to support a given population of organisms. any organisms living in a substrate indicate an increase in trophic state of the substrate. the only way nutrients will go away is if we export detritus from the substrate. as long as detritus (nutrients) are exported at a rate that matches the trophic state one wants to emulate, all is good. the bigger the nutrient sink the greater the margin for error.

substrates are nothing but a tool. they can be a very useful tool, but as with any tool it needs to be maintained in order to function at its best.

why are we trying to dilute anything? remove it and be done with the problem. use the substrate to collect nutrients for X amount of time, than replace the substrate and start over. just replacing the tool. restarting the nutrient sink. another X amount of time of easy maintenance. it is all about how you want to spend YOUR maintenance resources.

mineralization is not what we want. the point is to remove the organic material before it has a chance to decompose. letting detritus decompose leads to almost all of the problems we fight as aquarist. low alk (bacteria needing C for decomposition), high inorganic N and P (waste products of organic decomposition), low pH (CO2 is a byproduct of organic decomposition).

G~

I would disagree. It seems much more effective to let organic matter decompose; allow algae, bacteria and microfauna to make use of the resulting nutrients and then harvest out the algae, bacteria and microfauna. For a number of reasons. First - healthy algae, bacteria & microfauna populations provide food for your fish and corals. Most fish and corals prefer live food and prefer to feed throughout the day. Second - algae, bacteria & microfauna will remove nutrients from a system far better and faster than any aquarist. They are on the job 24/7. Third - a diverse population of algae, bacteria & microfauna can adapt to the changing chemical composition of your tank. As often noted, diversity appears to diminish over time as certain species of algae, bacteria and microfauna can become dominant in a tank. But the dominant species can and will change over time as tank conditions change. The ability of your tank ecosystem to adapt adds a level of stability that cannot be replicated by water changes, substrate siphoning and filter socks. Fourth - I personally find it to be much, much less work to empty a skimmer of bacteria and pull out a handful of chaeto and worms as compared to siphoning a sand bed, cleaning out filter socks and changing water. But that's just me. I can also sell the chaeto and microfauna. Not as easy to sell pre-decomposed organic waste. And finally - I just think it is more interesting to let the tank work as a complete system. Your approach seems much like growing a plant in a greenhouse. Which is cool. But not for me.

For what it is worth, my tank is now 31 years old and I have never siphoned out the first speck of detritus.

 

[tweeter]

I would disagree. It seems much more effective to let organic matter decompose; allow algae, bacteria and microfauna to make use of the resulting nutrients and then harvest out the algae, bacteria and microfauna. For a number of reasons. First - healthy algae, bacteria & microfauna populations provide food for your fish and corals. Most fish and corals prefer live food and prefer to feed throughout the day. Second - algae, bacteria & microfauna will remove nutrients from a system far better and faster than any aquarist. They are on the job 24/7. Third - a diverse population of algae, bacteria & microfauna can adapt to the changing chemical composition of your tank. As often noted, diversity appears to diminish over time as certain species of algae, bacteria and microfauna can become dominant in a tank. But the dominant species can and will change over time as tank conditions change. The ability of your tank ecosystem to adapt adds a level of stability that cannot be replicated by water changes, substrate siphoning and filter socks. Fourth - I personally find it to be much, much less work to empty a skimmer of bacteria and pull out a handful of chaeto and worms as compared to siphoning a sand bed, cleaning out filter socks and changing water. But that's just me. I can also sell the chaeto and microfauna. Not as easy to sell pre-decomposed organic waste. And finally - I just think it is more interesting to let the tank work as a complete system. Your approach seems much like growing a plant in a greenhouse. Which is cool. But not for me.

For what it is worth, my tank is now 31 years old and I have never siphoned out the first speck of detritus.

I know this question has been asked a million times. Yes, here it comes...what light do you use to grow your cheat? I know that the Kessil is probably the best, but I can't afford to buy a $350.00 light to grow cheat. Is there another cheaper one that will work?

 

[brandon429]

Scott I believe you can have one run that long hands off. its gotta be biggish though, that's no 50 gallon predicted ? can you post a pic

most of the mega old ones are above 100 g volume inclu sumps et al

I can envision in/out/mineralization constants that work in a perfect tune its just so hard to repeatably earn

am expecting no marked heavy fish bioloading as well can you post a pic real q

occasionally we simply find an old berlin system and nothing fancy, that's the thing we all strived for in the 90s. is yours classic berlin/nonsupports other than skimmage

Reducing our measurement/comparison to berlin-only systems really shores up the results.

that old berlin approach of sand, rock, no other offset other than skimming...that really highlights the workings of a hands off sandbed nicely given anything over sixty mos

 

[Scott Campbell]

I know this question has been asked a million times. Yes, here it comes...what light do you use to grow your cheat? I know that the Kessil is probably the best, but I can't afford to buy a $350.00 light to grow cheat. Is there another cheaper one that will work?

I have always just used cheap plant grow lights. I used to use incandescent grow light bulbs I bought at the hardware store. Now I buy LED bulbs from Amazon. They are usually about $30 each. But I use 3 bulbs rather high above my refugium tank as I have some mangrove plants as well. Have been intrigued by the Kessil as well but I would still need something for the mangroves.

 

[Scott Campbell]

Scott I believe you can have one run that long hands off. its gotta be biggish though, that's no 50 gallon predicted ? can you post a pic

most of the mega old ones are above 100 g volume inclu sumps et al

I can envision in/out/mineralization constants that work in a perfect tune its just so hard to repeatably earn

am expecting no marked heavy fish bioloading as well can you post a pic real q

occasionally we simply find an old berlin system and nothing fancy, that's the thing we all strived for in the 90s. is yours classic berlin/nonsupports other than skimmage

Reducing our measurement/comparison to berlin-only systems really shores up the results.

that old berlin approach of sand, rock, no other offset other than skimming...that really highlights the workings of a hands off sandbed nicely given anything over sixty mos

My main tank is 150 gallons. There is a 20 gallon refugium and a 20 gallon sump. I have 6 fish - yellow tang, foxface, melanurus wrasse, sailfin blenny and two anthias.

I grow a lot of macroalgae and I carbon dose.

 

[Paul B]

remove it and be done with the problem. use the substrate to collect nutrients for X amount of time, than replace the substrate and start over. just replacing the tool. restarting the nutrient sink. another X amount of time of easy maintenance. it is all about how you want to spend YOUR maintenance resources.

I have not replaced my gravel in over 50 years, Am I bad?

 

[NY_Caveman]

detritus is a giant liability unless its planned for, and offset, carefully, then its feed reserves.

I would agree with this. Many people use sand for aesthetic reasons, probably without even thinking much about it. Too often I bet they do not consider its management or limits.

I used many at the same time. Macroalgae, organic carbon (vinegar) dosing, GFO, large rock filled refugia, GAC, skimming, and 1% daily water changes.

Randy let detritus accumulate, but had a massive, diverse, thought out management system in place

In nature the benthic region is a nutrient sink as well. It consists of detrivores, scavengers, algae and all of the waste, death and decay that falls from above. The coral reef absolutely relies on the nutrients the benthic region provides as natural seawater itself does not provide the supply needed.

In a closed system there are two important differences:

1. there is much less diversity in the substrate
2. the saltwater is not continuously replenished from a fresh source (ie. the open ocean)

I will not be dramatic and say sand is a ticking time bomb, but when one uses it, they must be aware that it will eventually reach its storage limit and need to be replaced. Manual stirring and other methods may help manage this limit, but it will still be reached.

@brandon429 I think makes another good point that smaller tanks have greater risk. I think many, especially those new to the hobby using AIO nano aquariums, believe sand is a must, or are sold on the idea that sand is beneficial. I do not believe it is necessary, natural or beneficial. I see only two reasons to use sand: aesthetics or specific livestock needs. Both are quite valid reasons. Nonetheless, the limits should be considered.

 

[jda]

I like to get it out. I shop-vac my sump every few months and gravel-vac my sand starting in year four of a tank. However, I have .1n and .01p and it does not seem to be a phosphate or nitrate sink like people think. If you put the stuff in the sump into some fresh salt mix, the nitrate never climbs. Although I like to get it out, I am in no real hurry.

If there was organics or building blocks in the stuff, an effective, diverse tank would have long scavenged the vast majority of it already. Dr. Holmes-Farley opined decades ago that most phosphate leaves animals in the urine (I am going off of memory here from the other board).

I could on for hours about sand, but the short story is that the sand is never the issue... it is the hobbyist. The sand can bind a massive amount of phosphate if the reefer is lazy... and mask bad habits. The sand can accumulate a whole bunch of detritus and "gum up the works" where the sand is not processing nitrate into nitrogen gas anymore or allowing the microfauna a good home. A well maintained tank and sand bed can last forever. Is anybody old enough to remember the "old tank syndrome" craze from a decade or two ago? This was basically a sand bed that was bound full of phosphate and did not hide the lack of maintenance anymore.

 

[brandon429]

Paul

You do the most detritus offsetting of anyone on this entire site. If you turned off your rugf, never diatom filter cleaned again, reverse the rugf, then system goes plant dominant

Thats not a slight on the approach, if tasked with making a 45 yr system I wouldn’t try to reinvent the wheel I’d do what you are doing. Since the tank didn’t start with the current array but rather arrived there, some of the driving force has been offsetting nutrient loading it’s just fun to ponder which portions are detritus and which are animal contributions considering how diverse your stocking / water supply is



Scott if you would test the bottom mud sample that would reveal if you are capping off waste or indeed reducing it

Not that your results would change immediately, that tank is sharp and not invaded for sure

But it would help to at least make eduguesses about lifespan limits / projections if the nitrate potential was high in a dredge test sample. if it’s low then your bed is running the right way. What the water column tests for nitrate v the bottom mud sample after forty hours aeration is thread gold considering your bed age.

 

[madweazl]

We moved into our new home last week necessitating a transfer of the tank. I have an acropora dominated 75g with a 30g sump (total volume of approx 75g). The tank has approx 50lb of rock (5lb of Fiji live and the rest made up of BRS reef saver) along with 120lbs of Nature's Ocean bio-active black sand. I vacuum the sand two or three times per year but it is always surprisingly clean (I get some muck out, just not nearly as much as I would have suspected given how heavily I feed).

For the move, I purchased a 65g tank to setup in the new house to act as a transition tank. No sump, just heaters and a pair of Jebao PP8s for flow. I transferred the rock but dumped the sand into two 5g buckets. The sand sat in the buckets for 3.5 days; they were in the house at a temp of 75°. Once I got the 75g moved and set back up, I placed the rock and corals back into it (the fish and other inverts remained in the 65g) along with the sand. I didnt rinse it, didnt do anything with it but dump it back in the tank. After about two hours I checked for ammonia and nitrite with none detected so I dumped the fish and inverts back in. No issues what-so-ever. Oh, the tank was filled with 50g of fresh mixed IO and the remaining 25g came from the transfer tank (filled with the original water from the 75g). This was completed on May 3rd. My normal test routine is on Saturdays while I mix 10g of fresh water for a change on Sunday; I test alkalinity, calcium, magnesium, phosphate, and nitrate. Nitrates are typically <1ppm (usually less than half that using a Salifert kit but it gets hard to read down that low) and phosphates are typically <.07ppm (Hanna ULR). On Saturday, nitrates were 5ppm and phosphates were .077. I have not tested again this week but everything looks completely normal and I had to increase alkalinity dosing slightly higher than prior to the move.

My point? I dont know what causes this "mini-cycle" madness or some of the other craziness that gets blamed on moving sand around but I find the accounts less and less credible as time goes by (now in my 22nd year of reefing). My sand sat in 5g buckets, for 80+ hours without excess water (I drained as much off as I could) and had very little measurable affect on anything. Maybe I just got "lucky" again... My overwhelming suspicion, as always, is that it takes a combination of multiple things going wrong to cause a catastrophe (provided the basics for life support are within reason).

My AquaticLog entries if anyone is interested.

 

[Scott Campbell]

In five years there will probably be dozens of threads asking how best to dose detritus.

1. Access to detritus is of course a factor. I'm not a big fan of sand. Simply because it is harder to sustain populations of microfauna sand dwellers. My tank is mostly rock with enough sand in the middle for my wrasse. If microfauna cannot get to the detritus then that can be a problem.
2. I believe the tank has to be large enough to support self-sustaining microfauna populations. Small tanks are at a disadvantage in this regard.
3. I believe there has to be size diversity within the microfauna so that the detritus can be continually processed until it is exhausted.
4. I think you need fish and corals that feed on the algae, bacteria and microfauna so that food input into the tank can be reduced. You can't overwhelm your tank's capacity to process detritus.
5. I think you need a refugium as a safe haven for the microfauna.

That said - I don't think my tank is some kind of statistical aberration. I don't really do anything crazy. I just think a lot of folks keep smallish tanks or keep a lot of fish for the size of their tank or keep fish that don't feed on worms and algae or just aren't all that concerned about maintaining algae and microfauna populations.

 

[brandon429]

You’re able to keep a nice balanced 10k appearing light without algae I’m jealous

Mine has to be all blue to be hassle free, I’m tired of 20K constant living room the MH/more daylight look actually shows what corals look like. Nice colonies

 

[NY_Caveman]

In five years there will probably be dozens of threads asking how best to dose detritus.

1. Access to detritus is of course a factor. I'm not a big fan of sand. Simply because it is harder to sustain populations of microfauna sand dwellers. My tank is mostly rock with enough sand in the middle for my wrasse. If microfauna cannot get to the detritus then that can be a problem.
2. I believe the tank has to be large enough to support self-sustaining microfauna populations. Small tanks are at a disadvantage in this regard.
3. I believe there has to be size diversity within the microfauna so that the detritus can be continually processed until it is exhausted.
4. I think you need fish and corals that feed on the algae, bacteria and microfauna so that food input into the tank can be reduced. You can't overwhelm your tank's capacity to process detritus.
5. I think you need a refugium as a safe haven for the microfauna.

That said - I don't think my tank is some kind of statistical aberration. I don't really do anything crazy. I just think a lot of folks keep smallish tanks or keep a lot of fish for the size of their tank or keep fish that don't feed on worms and algae or just aren't all that concerned about maintaining algae and microfauna populations.

Very good points. I would imagine a new reefer with an AIO using sand would be very hard pressed to find, or even consider, that balance. Throw in some dry, sterile rock and you can bet the problems will arise quickly.

 

[vetteguy53081]

I allow it however occasionally I do go in with a bulb ( similar to turkey baster) and loosen it so it is suspended rather than settled creating a film.

 

[minder_mano]

My pumps clog faster without filter socks, that means more maintenance which is not for me