Cryptic Biological Reactor

[PK_reef]

Cryptic Biological Reactor - How Effective are they? Any successful or failed experience?

 

[Randy Holmes-Farley Verified Community Expert]

There’s no clear evidence at how useful cryptic sponges and other organisms may be.

I like sponges and grow them intentionally in my display. But assertions that they and/or cryptic sponges in the numbers associated with a reef tank would have a significant effect on nutrients or even organics in a reef tank lack much evidence.

 

[Subsea]

Randy is correct. There is little recorded data with qualitative analysis.

After > 55 years of reefing, I replaced algae refugiuns with cryptic refugiuns. My end goal in display is to maintain diverse filter feeders and cryptic refugiums double as zooplankton reactors.

 

[Yanir34]

There’s no clear evidence at how useful cryptic sponges and other organisms may be.

I like sponges and grow them intentionally in my display. But assertions that they and/or cryptic sponges in the numbers associated with a reef tank would have a significant effect on nutrients or even organics in a reef tank lack much evidence.

Reef bum made very interesting video about his cryptic sump ,including Aquabiomax biodiversity tests .

 

[Koty]

Every niche in our tank adds to the diversity. Below are pics of my refuge, the overflow that is kept mostly in the dark (Aiptasia are white as they have little zooxanthella). And the last compartment in my sump, where I recently added a "real" yellow sponge. I am not sure it has any measurable reactor effect, but a reasonable assumption is that diversity may help "process" many types of organics.

 

[Yanir34]

Here are the results of reefbum about the biodiversity test that he did before and after the cryptic sump.

 

[Randy Holmes-Farley Verified Community Expert]

Is a higher diversity score desirable? Why?

 

[Science/G]

I "feel" good when I have large numbers of filter feeders growing in my display and or sump, but.....

 

[Sophie"s mom]

Cryptic Biological Reactor - How Effective are they? Any successful or failed experience?

I am following along because I just turned a canister filter into a cryptic zone. Fingers crossed.

 

[Yanir34]

Is a higher diversity score desirable? Why?

To my opinion, its more healthy system in terms of different groups of bacteria that working together,

 

[Randy Holmes-Farley Verified Community Expert]

To my opinion, its more healthy system in terms of different groups of bacteria that working together,

Ok, that’s a fine opinion, but it lacks any evidence in a reef tank. It’s also not clear the bacteria in a cryptic refugium are “working together” with the remainder of the tank.

If I add other sorts of different environments, such as a mangrove swamp or a simulated hydrothermal vent, or a rotting chunk of whale blubber, I’m sure that adds diversity too. Does that means it’s better for the reef tank?

I’m not at all saying the bacteria don’t matter. I think they matter a lot. But a single number of a diversity score seems to me more of a marketing thing than a clear indication of benefit.

 

[Biokabe]

Is a higher diversity score desirable? Why?

Yes, I would think that a higher diversity score is more desirable, with an important caveat.

If the only thing I can test is the number of species of bacteria, and I don't have a great way to understand what, exactly, each species does, then I would say that increasing the diversity of that group would be beneficial. With more species present, there is likely an increase in the ability of the bacterial population to process waste that would otherwise go to promoting undesirable outcomes. And if the population is diverse, it's less likely that any one particular population is going to dominate, so I am less likely to accumulate large amounts of waste product from that particular species.

Taking it to the extreme: If my microbiome only has a single species of bacteria, and that bacteria produces a waste product that nothing else can process, and that waste product is harmful to my tank at large, then I am going to have problems and will need to take active steps to mitigate that waste product. If my microbiome has 20 different species of bacteria that are all interdependent and, combined their waste products are all food for something else, then I have fewer problems and don't have to take as many steps to combat the buildup of toxic waste products.

In other words: In a vacuum, increasing the number of different "mouths" in my system increases the chances that all or most of the waste products will go towards increasing the biomass of desirable life rather than simply accumulating in the water and eventually needing to be removed through water changes or filtration.

The caveat to all of that being - if I actually know and understand what each species in my tank does, then I might do better with a less diverse system that has a higher density of desirable species. Because it's entirely possible that some of the lifeforms in my tank are actually causing me problems.

 

[Randy Holmes-Farley Verified Community Expert]

Ok, I understand what you are saying. I just don’t agree and I think you may be exaggerating how different bacteria species are in terms of what organics they consume and what wastes they release.

It may well be that many tanks with unusually low biodiversity have that as a detriment. That does not necessarily imply that any particular action that adds more species is a benefit.

 

[ReefGeezer]

I keep dark fuges in my system. One is in the sump and one is in the overflow partition. I do think they are beneficial to my system, but can offer no proof. I think they provide a nutrient pathway and provide input to the food web. It is not intended to manage nitrate or phosphate in the old school sense though.

I will stipulate that the same organisms that occupy a dark fuge exist on the underside of rocks in the display tank. The fuge simply provides more surface area where light is limited.

 

[Biokabe]

Ok, I understand what you are saying. I just don’t agree and I think you may be exaggerating how different bacteria species are in terms of what organics they consume and what wastes they release.

It may well be that many tanks with unusually low biodiversity have that as a detriment. That does not necessarily imply that any particular action that adds more species is a benefit.

Yeah, I am exaggerating. I often use hyperbole and simplified cases to reason how something might be true, because if the extreme case is true then it could transfer into the more complex case of reality. Spherical cows and all that.

In truth, I don't think it's a stretch to question whether diversity is really a good shorthand for reef health. If a tank can be healthy with a less diverse microbiome, and equally healthy with a more diverse microbiome, then it's probably safe to say that more doesn't equal better. For myself, I would say that there's probably a certain level of diversity that you want (to avoid monoculture and any potential problems that could cause), but beyond that it doesn't really matter that much. So if you go from one species to a dozen species, that's probably good. If you go from a dozen species to three dozen species, that might not matter.

I wouldn't say that it's a hard thing to test for, necessarily, but it's the kind of experiment that is likely prohibitively expensive to test for with dubious benefit.

 

[Yanir34]

@Randy Holmes-Farley
Here is interesting article about cryptic , DOC and other stuff.

https://reefbuilders.com/2024/06/21...hy-reef-tank-heres-a-new-method-to-manage-it/

 

[Yanir34]

Another fact (that tested by scientists on the article) is that harmful pathogens will multiply faster in rich DOC environment.
The sponges "eats" this DOC , and therefore reduce the overall pathogens population.

 

[Randy Holmes-Farley Verified Community Expert]

I do not doubt many of the things noted in that and similar articles. But the point stands that no one has measured how much effect a cryptic filter has on doc in a typical reef tank. I’m personally skeptical for several simple reasons, but my reasons do not provide evidence against it working usefully.

Primary reason for skepticism: when organisms consume organics, they do so for two main reasons. To get energy and to grow (build more tissues). I have taken apart dark zones that were in my tank for years, and while there are some sponges and other organisms present, it did not amount to a lot of organism mass. I was even dosing silicate for years to boost sponges.

That then only leaves the need for energy as a potential sink for organics that get metabolized. I understand that many of these organisms promote flow though themselves to capture dissolved and particulate matter, but that does not strike me as a large energy consuming process (like a swimming fish) that would account for a large need for taking up doc.

Thus, while I certainly do not dispute that they are capable of removing dissolved and particulate organics from the water, I consider it unproven to suggest they make an important difference.