High Levels of TOC in the Reef

[Daniel Almeida Prado]

I fail to see any utility to doing an oxygen demand test, unless folks are suspicious that the TOC test is inaccurate.

At best, it will either show

1. BOD is unusually high. That confirms the TOC is high. What then that is different than if you do not confirm it?

2. BOD is not unusually high. Then either the TOC test is wrong, or the organic involved is not readily biodegraded. What then?

Randy,

I understand your point of view, but my answer is the same of Lasse. Doing the BOD5 tests I can attack the TOC problem, definitely.

Rgds,

Daniel

 

[Daniel Almeida Prado]

IMO - it is of a huge importance to know the nature of the high TOC (It has been 6 test - all with high TOC). If you have a unusually high BOD - you know that the organic involved is readily biodegraded and - still IMO - probably not the reasons for your poor coral surviving. You can close that track - IMO

If the BOD is normal or low - you know that the high TOC is caused by not readily biodegraded organic carbon sources that can have potential toxic characteristics (there is a lot of them). In this case - it can be wise to follow this track and try to identify the compound.

I have seen a lot of N-DOC analysis and all the time the TOC level have followed the expected path - I do not suspect that 6 test showing around the same high TOC level should be false - if one of six - yes maybe - but not all N-DOC tests showing high values

I´m not sure that it is the high TOC that is the root to the problem OP have had for many years with this setup - but it is one parameter sticking out in his tests and my way of attacking problems like this is to try to follow a track in order to either rule out or confirm it. I always try to follow a simple yes or no schedule when I try to tack down problems

In this case - we have - still IMO - two tracks to follow (that can be the same track because many anti fungus chemicals is based on organic carbon) The two things I (and some others) have suggest is to try too figure out if the pipes used have been treated against mold and to get an indication if the high TOC level is caused of readily biodegraded or not readily biodegraded organic carbon sources. If the pipes is not treated - case closed. If BOD is high - case closed. If the pipes is treated and/or BOD is low - this paths is worth to go further with - IMO

Sincerely Lasse

Lasse,

Thank you very much!!!! I complete agree with you!!!! I am starting the BOD5 test and I am waiting a answer fo the pipes company about the eventually mold treatment!!!

Rgds,

Daniel

 

[Daniel Almeida Prado]

How do the corals die? That might give clues to something. How long does it take generally?

Have you measured par from your maxspect leds?

Cory,

The softs are more resistent, they live aproximately 6 months. The LPSs, lives only 3 months. The SPSs dies fast, 1-2 weeks. The SPSs not open the polips, they start to lose color, have a dry appearance, and start to shave.

I always measure the PAR. NO issues!!!!

Rgds,

Daniel

 

[Daniel Almeida Prado]

Maybe some pics of inside the tank would help too. I only see equipment pics.

Hello Kenchilada,

I will take some pictures and I will post here.

Rgds,

Daniel

 

[Cory]

Cory,

The softs are more resistent, they live aproximately 6 months. The LPSs, lives only 3 months. The SPSs dies fast, 1-2 weeks. The SPSs not open the polips, they start to lose color, have a dry appearance, and start to shave.

I always measure the PAR. NO issues!!!!

Rgds,

Daniel

That sounds like they are starving. Hows no3 and po4?

 

[Daniel Almeida Prado]

That sounds like they are starving. Hows no3 and po4?

As show in the ICP test Po4 is ~0.01 and No3 ~0.10

 

[Daniel Almeida Prado]

Hello Guys,

I started the BOD5. The first measure in the Sera Test O2 with tank water sample was 4mg/l. After 1 hour of airation the value was the same 4mg/l. Let's wait for the 5 next days.

Rgds,

Daniel

 

[Lasse]

Hello Guys,

I started the BOD5. The first measure in the Sera Test O2 with tank water sample was 4mg/l. After 1 hour of airation the value was the same 4mg/l. Let's wait for the 5 next days.

Rgds,

Daniel

If the test is accurate - you are low in oxygen - after an hour of aeration - you should be between 6 to 7 mg/L if your salinity is around 35 psu, temperature around 25 and at ocean level. Whats your salinity. temperature and altitude?

Sincerely Lasse

 

[Randy Holmes-Farley]

Randy,

I understand your point of view, but my answer is the same of Lasse. Doing the BOD5 tests I can attack the TOC problem, definitely.

Rgds,

Daniel

I understand. I personally would not do it as I do not see the benefit, but we will see if it gives you a solution to the coral problems.

In the meantime, there is zero downside to more aggressively using GAC since that is, IMO, the first solution to try to treat the high TOC no matter what happens in the BOD test.

 

[Randy Holmes-Farley]

IMO - it is of a huge importance to know the nature of the high TOC (It has been 6 test - all with high TOC). If you have a unusually high BOD - you know that the organic involved is readily biodegraded and - still IMO - probably not the reasons for your poor coral surviving. You can close that track - IMO

If the BOD is normal or low - you know that the high TOC is caused by not readily biodegraded organic carbon sources that can have potential toxic characteristics (there is a lot of them). In this case - it can be wise to follow this track and try to identify the compound.

I have seen a lot of N-DOC analysis and all the time the TOC level have followed the expected path - I do not suspect that 6 test showing around the same high TOC level should be false - if one of six - yes maybe - but not all N-DOC tests showing high values

I´m not sure that it is the high TOC that is the root to the problem OP have had for many years with this setup - but it is one parameter sticking out in his tests and my way of attacking problems like this is to try to follow a track in order to either rule out or confirm it. I always try to follow a simple yes or no schedule when I try to tack down problems

In this case - we have - still IMO - two tracks to follow (that can be the same track because many anti fungus chemicals is based on organic carbon) The two things I (and some others) have suggest is to try too figure out if the pipes used have been treated against mold and to get an indication if the high TOC level is caused of readily biodegraded or not readily biodegraded organic carbon sources. If the pipes is not treated - case closed. If BOD is high - case closed. If the pipes is treated and/or BOD is low - this paths is worth to go further with - IMO

Sincerely Lasse

I do not think it is reasonable to assume that a BOD result will tell you if the organic(s) involved are toxic or not.

If one is concerned about the organics, they should be reduced to see if it helps, and using GAC would be the bet first start, IMO.

 

[Lasse]

I do not think it is reasonable to assume that a BOD result will tell you if the organic(s) involved are toxic or not.

If one is concerned about the organics, they should be reduced to see if it helps, and using GAC would be the bet first start, IMO.

That´s right - you will not know if the organic(s) involved is toxic or not - but it will give you an indication if there can be some toxic substances in the TOC pool. The readily biodegraded organic carbon sources are likely not toxic (bacteria can be sensitive too) and there is a lot of toxic substance in the not readily biodegraded organic carbon pool. The BOD is a biological tool and will give you two possible pathways to explore if it is low or normal. Either - there is something toxic for at least bacteria in the sample and/or it is organic carbons sources that are non readily biodegraded organic carbon sources - the largest group (IMO) of toxic organic carbon sources.

The GFO will take away mostly the large non readily biodegraded organic molecules (not sure about the smaller ones - like nitrile - a common used anti mold agent for rubber gaskets and gloves) but leave most of the readily biodegraded organic carbon compounds like sugar, alcohols and other commonly used DOC substances still in the water.

Yes - using GAC in aggressive mode is a way to see the type of organic carbon sources too but in this case - at least my first step would be to investigate the BOD. But I´m not sure if it can be done with help of the oxygen test @Daniel Almeida Prado will use,

Sincerely Lasse

 

[Daniel Almeida Prado]

If the test is accurate - you are low in oxygen - after an hour of aeration - you should be between 6 to 7 mg/L if your salinity is around 35 psu, temperature around 25 and at ocean level. Whats your salinity. temperature and altitude?

Sincerely Lasse

Hello Lasse,

I repeat the measure of the tank water and tank water after the airation. The result was the same, this time I airate the water for 2 hours - 4 mg/l.

The salinity is 1024 (my salinity tester Milwaukee dont show psu unit), temperature 24.5oC and the altitude is 541m.

The O2 rate is too low?

Many thanks,

Daniel

 

[Daniel Almeida Prado]

I understand. I personally would not do it as I do not see the benefit, but we will see if it gives you a solution to the coral problems.

In the meantime, there is zero downside to more aggressively using GAC since that is, IMO, the first solution to try to treat the high TOC no matter what happens in the BOD test.

Hello Randy,

Thank you very much. I apreciate.

I will use GAC as you recommend, as soon the BOD5 ends.

Rgds,

Daniel

 

[Cory]

As show in the ICP test Po4 is ~0.01 and No3 ~0.10

Wouldn't those numbers be basically nearly zero? Can you experiment in a separate tank and dose no3 and po4 with a coral?

 

[Hans-Werner]

I am sorry that I did not read the complete threat, but at page 2 I saw what your problem is. TOC is maybe an indicator for bad overall conditions, that might be correct.
The reason for your problems is an extremely low phosphate concentration (12 µg/l = 12 ppb = 0.01 ppm). This is the reason why nitrate and TOC builds up and it is also the reason why all your corals die. Corals absolutely don't tolerate such wide N : P ratios (marked red by Triton) and low phosphate concentrations at the same time, see also here.

 

[Lasse]

@Daniel Almeida Prado You aquarium have been in function for over 6 years and you have reported the same problems for all these years - not only for hard corals but even for softies of different species. The very low PO4 and NO3 is a problem in every aquarium (IMO) in spite of other evenual problems. The question is now - have you have these low readings for all 6 years? If it turn out with a high BOD5 - @Hans-Werner :s suggestion maybe is the way to go.

IMO - it is important that you also try to validate your nitrate level - you report 0.1 ppm nitrate with your test - Triton report over 4 ppm in TN - corresponding to over 18 ppm NO3 if all was in that form. You report 0.1 in measured NO3 - this make no sense - Either is your own NO3 measurements totally wrong or the detected TN level by Triton refers to another source of N than NO3.

IMO - it is more and more important to track the source of the high organic C - because the result will decide which main path to follow. I agree with Hans-Werner (and others) that have point out the low PO4 concentrations - it needs to be raised. But - because of the long history of your problems - I´m not sure if it is the main problem for you.

Beside a possible treatment of the pipes (with anti mold agents) - you may have to look at the rubber gaskets too.

If they are nitrile treated - both the high TOC and the high TN can be explained - here is the general formula for nitrile:
R-N≡C. R is an optional organic compound

Sincerely Lasse

 

[Hans-Werner]

IMO - it is important that you also try to validate your nitrate level - you report 0.1 ppm nitrate with your test - Triton report over 4 ppm in TN - corresponding to over 18 ppm NO3 if all was in that form. You report 0.1 in measured NO3 - this make no sense - Either is your own NO3 measurements totally wrong or the detected TN level by Triton refers to another source of N than NO3.

Yes, correct what you pointed out, Lasse, thanks! It is not really nitrate, only calculated from the nitrogen concentration. There is another ratio, "N - NO3(N) Ratio" without number but also marked red. Most likely this means there is in fact only little nitrate but a lot of organic nitrogen and ammonium.

After elevating the phosphate concentration it may make sense also to think about a trace element supplementation. Phosphate as well as a lack of trace metals could cause an inhibition and stagnation of bacterial and other metabolic processes.

Shame on me. I should have studied the analysis more thoroughly. The phosphate concentration is 0.0108 ppm when scrolling down. A whole series of absolute beginners mistakes from my side when just checking phosphorus and N : P ratio.

 

[Hans-Werner]

error

 

[Lasse]

Yes, correct what you pointed out, Lasse, thanks! It is not really nitrate, only calculated from the nitrogen concentration. There is another ratio, "N - NO3(N) Ratio" without number but also marked red. Most likely this means there is in fact only little nitrate but a lot of organic nitrogen and ammonium.

After elevating the phosphate concentration it may make sense also to think about a trace element supplementation. Phosphate as well as a lack of trace metals could cause an inhibition and stagnation of bacterial and other metabolic processes.

Shame on me. I should have studied the analysis more thoroughly. The phosphate concentration is 0.0108 ppm when scrolling down. A whole series of absolute beginners mistakes from my side when just checking phosphorus and N : P ratio.

Nema problema - you write that you haven't read the whole thread and the information is scattered among many posts. And I missed the very low PO4 concentrations

I do not think that the reading of 0.1 ppm NO3 (by the OP) is correct - therefore its important to get another analysis of the NO3 and even the NO2. An unexpected high level of NO2 (above 0.05 - 0,1 ppm) can give some hints too - it will indicate a disturbed nitrification cycle in an 6 years old aquarium.

Sincerely Lasse

 

[Hans-Werner]

It is much easier to open two tabs parallel instead of switching back and forward when responding to a certain statement, analysis or parameters. I have to keep this in mind.

I think increasing phosphate concentration first and dosing trace elements then may act like releasing a break and everything may normalize a lot. This is what I would start with.