Biopellets causing Acropora to STN/RTN?

[SomeDude12]

Is there any evidence, that biopellets can cause STN/RTN? I recently began running biopellets on my 210 that all inhabitants moved from my 150. Many of the acro colonies have grown from small frags to 4-8" colonies. I'm experiencing 50-75% of my acro's experiencing slow tissue necrosis. Many I've dipped numerous occasions with iodine, trimmed above the line and still experiencing the STN. Another odd scenario is that it tends to be centralized/affected on the right side of the tank.

I ran biopellets for 12+ months on my 92, with no problems (so I'm not new to the usage of them). Same brand pellets (BRS) and reactor. Any suggestions and input is greatly appreciated. I'm tempted to halt running pellets. I'm not sure if this is the culprit, but I'm loosing colonies that took years go grow!

 

[Reefin' Dude]

why did you decide to start carbon dosing in the 210?

G~

 

[bigevill1]

I have heard that the low nutrient environment from carbon dosing can make higher alk an issue with SPS. Something where your alk should be in the 7-9 range, not the 10-12 range some people keep. If your alk is high try bringing it down. I have also found that dosing amino acids helps SPS and LPS when running any form of carbon dosing. Coral has to eat, and some PO4 and NO3 is needed to keep them happy.

 

[Reefin' Dude]

this is because the bacteria in the water column are now using up the free access elemental C produced by the biopellet reactor instead of using the elemental C from carbonate.

high alk is a real problem with SPS. when there is a large cesspool (read substrate) in the tank, the bacteria trying like crazy to use up the P in the substrate are using up a ton of carbonate. we associate this low alk with coral growth, but it is from the bacterial activity. when elemental carbon dosing the alk level tested is more accurate. the bacteria are not going to want to use the carbonate, and will use the free elemental C leaving more alk perceived for the coral. the higher the carbonate the more it gums up the photosynthesis pump, making it harder for the corals to perform photosynthesis. to much alk gets in the way of the formation of CO2.

unfortunately, due to the fact that we have not understood this relationship until recently and the fact that we had been believing that substrates were good, we are stuck with high alk salts as the norm instead of the exception. it is getting harder and harder to find properly balanced salts for those that want to run true oligotrophic systems.

G~

 

[SomeDude12]

why did you decide to start carbon dosing in the 210?

G~

As intended, to minimize Nitrates.

I have heard that the low nutrient environment from carbon dosing can make higher alk an issue with SPS. Something where your alk should be in the 7-9 range, not the 10-12 range some people keep. If your alk is high try bringing it down. I have also found that dosing amino acids helps SPS and LPS when running any form of carbon dosing. Coral has to eat, and some PO4 and NO3 is needed to keep them happy.

Alkalinity, last checked on the 18th of Sept, tested at 9.016 dkh. Calcium 460/470 & 10ppm Nitrates. Ultimately, I decided to utilize equipment I already had and considering this tank has a high bioload, it was a good idea. The lack of nutrients (nitrates and phos), is highly unlikely. Where my 92 was unable to support the growth of any macroalgae, the 210, has no problems. In reality, I'm dealing with higher Phosphates, then ideal.

 

[Reefin' Dude]

those levels are still very high over NSW levels. i have found no reason to use a Ca reactor on a tank that had 7 clams, 2 that were greater than 6" and plenty of SPS colonies and frags to cover the LR. i was able to maintain NSW levels with just a 5-10g water change a week and kalk in the top off. this was on a 125g tank.

bacteria are both our tanks greatest asset and its greatest liability. we do not want to think of all of the bacteria as a "single" organism, but like any organism, the bigger it is the more resources it uses up and the more waste it produces.

a high bioload of non-hermatypic organisms would not strip the water column of alk and Ca. a high bioload of bacteria on the other hand will strip a system of alk in a hurry in the search for elemental carbon.

G~

 

[SantaMonica]

I too have heard of strong pellets/vodka/etc hurting corals. Slows down scrubbers, too.

 

[Reefin' Dude]

of course. it switches the balance of power in nutrient uptake from the silly scrubber to the water borne bacteria. this is why carbon dosing "works".

G~

 

[jda]

Evidence? No. You won't find much of this in a hobby. Anecdotes and experiences? Sure. You can drive N and P too low, or down too quickly to cause SPS to STN and/or RTN.

I am a substrate user, have no detectable N or P in any of my heavily stocked SPS tanks since the late 1990s and I let the bacteria in the sand come to equilibrium on their own to hand the nitrate and process the phosphate naturally. I have never used a carbon source on my reefs (loved it on a FOWLR that I had) and I have had "clear" results on Saliftert test kits since they first came out. My N and P are low enough that I have to watch my alk getting above 8, or my SPS can lose color - I am on Tropic Marin Pro Reef at 5.5-6.0 alk salt without even dosing a single drop of carbon.

There are a bunch of different way to skin this cat. Any of them will work pretty well if you have a good plan and are committed and GO SLOW. Carbon dosing is very effective and puts the equilibrium on you - natural bacteria based puts the equilibrium in the tank. If you are committed, then stick with it, but perhaps slow down. It might not hurt to cut back a bit on your feedings - going with less messy food like NLS pellets and not so much frozen might really help for a while.

 

[rfequity]

Just want to chime in that bio-pellets almost killed all of my SPS. Started using them in June with a very slow ramp up process. Recently I noticed that all SPS was doing poorly. Even my monti caps were turning very pale. My nitrates are at 10PPM so I decided to go back to the old fashion way of WC to keep things in check. Within a week of unplugging the bio pellet reactor, the color is returning. Maybe it works for some, it sure did not for me.

 

[Reefin' Dude]

there maybe more than one way to skin a cat, but the point is still to skin the cat.

the skinned cat in our case is nutrient removal. if nutrients are not removed as quickly as they are coming in, than the system is becoming eutrophic, the cat is still growing fur. the unfortunate part is one group understands this, the other does not and still keeps sweeping the nutrients under the rug(sand) and pretending that the cat is skinned.

G~

 

[acesq]

there maybe more than one way to skin a cat, but the point is still to skin the cat.

the skinned cat in our case is nutrient removal. if nutrients are not removed as quickly as they are coming in, than the system is becoming eutrophic, the cat is still growing fur. the unfortunate part is one group understands this, the other does not and still keeps sweeping the nutrients under the rug(sand) and pretending that the cat is skinned.

G~

Reefin' Dude: what are the best practices for nutrient removal in a closed system intended for SPS? BB and carbon dosing? Shallow sand bed and carbon dosing? I certainly understand and agree with your posts on the subject here and in other threads, I just want to fine tune my systems. I've been running a 120 for three years with a shallow sand bed that I vacuum every two weeks along with a 15% water change and use a biopellet reactor for carbon dosing. I've not had many issues with anything other than a little Cyano that comes and goes, although I now feel that the sand has backed up with P and is causing a little algae outbreak along with the cyano. Time to change the sand. I have a new build starting and I'm trying to decide whether to epoxy a thin layer of sand on the bottom just for aesthetics (don't like the BB look) and stick with the biopellets or ???

 

[Reefin' Dude]

lots and lots of flow. i made nutrient export a top priority in my last system. had a sand embedded epoxy bottom with the bottom coarse of LR also embedded into the bottom. there was not any LR sitting on the bottom. flow was able to get to the entire bottom. i had over 12,500gph of flow in my 125. here is a link to the build thread.

what i will do differently in my next build is move more water through the skimmer. i think skimmers nowadays are wimpy. they are efficient, but they just are not moving enough water through them. i hope to move close to 10x water through my skimmer, with a UV just in front of the skimmer that can handle that amount of flow also. i also plan on putting in a conical settling tank that can match this flow rate. plumbed immediately after the overflow and before the UV and skimmer. i had a 30g ready go, but i had to take down my tank before plumbing it in. i will probably need at least a 60g one for the next build. a conical settling tank will settle out all detritus into a single area. to make it better a valve on the bottom of the cone is used to drain water for a water change along with the removal of all detritus accumulated since the last water change.

i think carbon dosing can be useful, but only in a specific set of circumstances. there is so much micro food being put into the tank that water borne bacteria are the ones creating the inorganic nutrients. i do not think that carbon dosing should be used on tanks where the majority of the inorganic P and N are created by detritus/surface dwelling bacteria. i think in these cases the balance of carbon power is pushed away from the bacteria that are really doing the most amount of good, and feeding the bacteria that are doing the masking of the affects allowing more inorganic P to bind to the calcium carbonate structures.

G~

 

[acesq]

I certainly agree with taking the detritus out of the tank before it has a chance to settle and decay. However, I'm not sure I understand this:

i do not think that carbon dosing should be used on tanks where the majority of the inorganic P and N are created by detritus/surface dwelling bacteria. i think in these cases the balance of carbon power is pushed away from the bacteria that are really doing the most amount of good, and feeding the bacteria that are doing the masking of the affects allowing more inorganic P to bind to the calcium carbonate structures.

What tanks have the majority of inorganic P and N created by other than detritus/surface dwelling bacteria?

The balance of power thing really has me stumped. Can you explain your take on the process that allows one group of bacteria sited on a biopellet to mask the effects of inorganic P binding and to take power from bacteria sited elsewhere (which would be sand and rock and to a much lesser extent in the water column)?
Art

 

[Reefin' Dude]

What tanks have the majority of inorganic P and N created by other than detritus/surface dwelling bacteria?

very few. that is true. systems where detritus is heavily skimmed off or siphoned out in a timely manner will have very little detritus to supply inorganic N and P. a well designed true BB system will come very close.

The balance of power thing really has me stumped. Can you explain your take on the process that allows one group of bacteria sited on a biopellet to mask the effects of inorganic P binding and to take power from bacteria sited elsewhere (which would be sand and rock and to a much lesser extent in the water column)?
Art

it is how carbon dosing works. it provides the bacteria in the water column easy access to a carbon source, so that they can use up any available inorganic N and P. these bacteria are then skimmed off as a nutrient export. it is this bacterial activity that provides the nice low inorganic N and P levels people see when carbon dosing. providing the water borne bacteria all of the resources they need, starves the bacteria on the calcium carbonate surfaces. allowing the calcium carbonate to be in charge, doing what it does best. absorb phosphates. without an easy available elemental C for bacteria to use, they can not cleave the P off of the calcium carbonate. even though the water tests really well, the total system is still becoming more eutrophic. the calcium carbonate is just getting more and more full of P. how many people have you heard that have algae problems when they stop carbon dosing? ever wonder why?

bacteria need resources. we all focus on the nitrogenous compounds, but like any life, they also need elemental P, C, and O.

G~

 

[MisterP]

Reefindude----I'm with you on most of this but I'm kind of confused on the way the last post reads.

When you say "allowing the calcium carbonate to be in charge, doing what it does best. absorb phosphates." This is a good thing right?

Also when saying "even though the water tests really well, the total system is still becoming more eutrophic. the calcium carbonate is just getting more and more full of P." This is still a good thing right..the way it reads to me this is not so great but the other comment above seems to read contradictory to me.

I guess my confusion lies in the fact I thought the goal was to dose C to allow the bacteria to process more N and P in the specific ratio that C, N and P exist with C and N being the limiting factor for removing P, thus some folks may dose C and N in order to process more P. If this P is bound to the rock and substrate...Would this be good or bad?

If it is bound in the substrate would it just be easier to scoop out some small amount of substrate every week and replace it with fresh non-P bound substrate?

What happens when the P is bound in rock...obviously rock cant just be replaced like substrate. Are bacteria in the water column still able to "unbind" (if thats even a word) P?

 

[dkeller_nc]

SomeDude12 - Not sure if you're still reading this thread, but here are a couple of thoughts on biopellets.

"Biopellets" are polysaccharides. The source of polysaccharide varies - there are various mixtures of alginate, guar gum, dextran and even corn starch. But fundamentally, they are all polymerized sugars. In the presence of certain bacterial enzymes and also through abiotic mechanisms, the bonds between these sugars are cleaved and the individual (sugar) monomers are dissolved in solution.

Various forms of "Carbon dosing" tend to be lumped into a catch-all phrase, but it's incorrect from a chemistry and biochemistry standpoint to think of the typical sources of organic carbon added to seawater as being completely equivalent. It is true that ultimately, it doesn't really matter what species or range of species of bacteria are being growth-promoted in the system with regard to consumption of carbon, nitrate and phosphate; they all require and therefore consume these elements in rough proportion to the Redfield ratio.

However, there is at least one scientific study that suggests that the type of carbon dosed does indeed have different affects on coral. Whether this is the influence of the actual molecular species of carbon or the types of bacterial species that are produced is unclear. Neverthless, this study did find that dosing of various sugars and polysaccharides was associated with mortality in several species of interest to aquarists in a roughly 3 week time frame. The authors noted that the pathology proceeded by tissue-edge necrosis - it could be argued that this is a description of STN.

To my knowledge, this type of study has not been conducted with the two other typical sources of carbon dosing: acetic acid (vinegar) and ethanol (vodka).

Controlling the free sugar concentration in solution with a biopellet reactor is very difficult since there is an overwhelming reservoir of the source polysaccharide, and the rate of dissolution depends on many factors that are also difficult to control. It's clear from net forums that many people run biopellets very successfully, but there are also a lot of anecdotal reports of serious issues.

Given this knowledge and at least the suggestion of serious coral mortality associated with high saccharide concentrations in seawater, I would not personally run biopellets in my reef tanks. It's just far too easy to dose vinegar or (less preferably) ethanol, and it's really easy to control the dose exactly.

 

[lanshark]

To be honest guys, i was hopeful as i began reading this thread of learning something to improve the odds of keeping a sustained SPS tank. Unfortunately, the take away for me is for 98 out of 100 who attempt SPS will not succeed long term. We need solutions and proven techniques. Impressive vocabularies though... As RC is suppose to be an open discussion forum, the chemists like yourselves need to put the hard truth out there as they know it, closed systems cannot support SPS animals long term for the vast majority of hobbiests .... Jus my opinion... BTW, I am starting new build and not giving up just yet....

 

[dkeller_nc]

Hmm - I wouldn't necessarily conclude that, at least that percentage of failure. If you peruse the SPS forum, there's lots of folks that have SPS tanks that are quite successful, and at least in my opinion, it's not particularly difficult.

What you'll want to consider as well is that reading forum posts heavily skews an impression towards "lots of problems" simply because people post when they have issues, but don't necessarily post "success".

I guess it also depends on what you mean by "long term", but there are quite a number of species/strains of acropora, montipora, and other SPS corals that have been in the hobby for 10 to 15 years or more, and that wouldn't really be possible if most people failed to keep these corals alive and healthy.

 

[SantaMonica]

"even though the water tests really well, the total system is still becoming more eutrophic. the calcium carbonate is just getting more and more full of P." This is still a good thing right.

No. Rock will fill up in about a year, and you are back to problems.

C and N being the limiting factor for removing P

C is limiting; not N. DOC would be much higher, but bacteria eat it faster than it can accumulate. There is plenty of N in the water even when it tests zero; Urea alone is a constant from the fish; that's why your glass will always will need cleaning. Urea is such small particle size that it has large surface area and is broken down by bacteria immediately.

If it is bound in the substrate would it just be easier to scoop out some small amount of substrate every week and replace it with fresh non-P bound substrate?

This is not very efficient. Plus you lose the life in the sand. Just cultivate some algae to remove the P. That's what algae does.

What happens when the P is bound in rock

Once it "fill up" you get more problem. The rock equalizes with the amount of P in the water. So, keep the P in the water as low as possible with high continuous export.