Testing for dissolved organics in a seahorse tank.

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rayjay

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I'd most definitely be interested in determining a range at which seahorse bacterial infections were more likely to occur and if I was younger with all my tanks and species (I've had 7 over the last 20 yrs) I'd give it a go even with the expense.
IF we could determine a point, and IF we could have a hobbyist test kit, then we can spread the information around the community and hopefully many seahorse lives could be spared. However, I'm down to one last species now, having to phase out due to health, and once gone that will be the end for me as a keeper.
As long as my cognitive impairment doesn't get too bad I'll continue the online helping with the hobby.
IF the problem ISN'T due to elevated DO, my thoughts are that we know right now that keeping water quality with low DO provides MUCH greater chances of success in long term keeping so if it ISN'T DO, whatever it actually is, is ALSO being controlled by keeping DO from expanding.
That would mean if we had the means to hobbyist test the DO, and find a range to work with, we can have success even though we may not know the actual cause of the infections.
At the moment, the controls we use for DO are varied depending on how the hobbyist sets up their system.
It usually boils down to excellent filtration including filter socks, that should be cleaned out twice a week, greatly oversized skimmer, GAC if no skimmer is used, or, just extra insurance if a skimmer is used. Large volume water changes on a frequent basis. Some use products like Mic-F to try to out compete the nasties and some treat with peroxide. (makes skimmers go nuts)
Husbandry is done to extremes as in not leaving any food in the tank to decay, having a minimum of 10X water flow, 20X is better, set up to try to keep the uneaten food and detritus in the water column long enough to be captured by the filtration, and usually any that DOES settle, the majority ends up in one spot, easily siphoned out.
I usually recommend experimenting with the feeding protocol so that you feed only what they will consume in 12-15 minutes, first because any more basically get pushed through their rudimentary digestive tract without extracting the little nutrition capable of being extracted, thus expelling more nutrient laden feces, again leading to water quality deterioration. Seahorses fed smaller amounts more times a day IME, develop better immunity to these nasty bacteria like the vibrio types that usually cause the most problems.
There is probably more but to get everything out of my memory at one sitting is problematic these days.
In the end, probably the majority of seahorse hobbyists out there that would really love to be able to know for instance if the frequency and size of the water changes they do are sufficient, lacking, or overdone.
 
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Randy Holmes-Farley

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I would just add that many of the things folks do to reduce organics also likely reduce bacteria, including pathogenic ones, independent of any reduction in organics directly. This, determining that an effect, if there is one, is due to reduced organics and not direct export of bacteria is difficult.

In any case, your original posts was how to test for organics, and they way to test is exactly what a DOC and TOC test accomplish. It there was a simpler or cheaper way, there would not be so many companies offering these tests.
 
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I think GAC is under-rated in these discussions because it's so low-tech.
There's a number of markers I've looked at that indirectly point to the organic content of water....
1) yellow-ness of the water - easy to observe if you have a long enough path length and a white background (white bucket test: bucket of new saltwater, next to a bucket of old water) but it's really hard to generate any numerical comparison for this.
2) UV-fluorescence of the water: 350-400nm UV will excite a lot of organic compounds and make them fluoresce blue-green. This is a subset of the yellow-ing organic compounds. with a spectrometer ($), you can generate numerical comparisons here.
3) Chlorine demand - bleach will react with organic N compounds like proteins and amino acids and so a free chlorine test (cheap hanna test kits) can show you how much bleach your tank water can consume.
4) BOD: the amount of O2 in the water that gets consumed when stored sealed. It's a measure of the digestible compounds in the water and the size of the organism metabolism.
(interestingly 1 and 4 measure a sort of separate subsets of dissolved organics: the yellow compounds aren't usually very digestible and the digestible ones aren't often that yellow)

These all correlate somewhat with the overall level of dissolved organic material. Some better than others. But what I find interesting is that all of those markers are strongly decreased by treatment with GAC.

Would upping the amount and frequency of GAC be more helpful than say ozone or UV for seahorse water remediation? I don't know - but I know it removes a bunch of the above measurable things that get left behind by skimming.

Ozone + ORP gives a nice measurable target and may provide some protection against disease. UV destroys ozone so those probably won't play well together. But I think either ozone or UV would work well with GAC.
 
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I think GAC is under-rated in these discussions because it's so low-tech.
There's a number of markers I've looked at that indirectly point to the organic content of water....
[/QUOTE]

1) yellow-ness of the water - easy to observe if you have a long enough path length and a white background (white bucket test: bucket of new saltwater, next to a bucket of old water) but it's really hard to generate any numerical comparison for this.
[/QUOTE]
In 20 yrs, I've NEVER seen any yellowing in a seahorse tank, probably because of so many large water changes and use of skimmers and GAC.
2) UV-fluorescence of the water: 350-400nm UV will excite a lot of organic compounds and make them fluoresce blue-green. This is a subset of the yellow-ing organic compounds. with a spectrometer ($), you can generate numerical comparisons here.
[/QUOTE]
I think out of the range of a hobbyist pocketbook.
3) Chlorine demand - bleach will react with organic N compounds like proteins and amino acids and so a free chlorine test (cheap hanna test kits) can show you how much bleach your tank water can consume.
[/QUOTE]
I think I recall some mention of this earlier in the thread but I don't really understand how it works.
It is quite interesting but I'll have to do some research to understand that relationship of bleach and organic N compounds. I have NO understanding of chemistry and most of it's terms so I have to find something that can explain to me in layman terms that hopefully I CAN understand.
I also don't know just how much of the dissolved organics in a marine tank are N compounds to know if it would be a relevant factor for determining DO levels. If it's a large enough portion of DO then it can be a way to do testing to find a range that we want to avoid.
If we could get hobbyists to immediately do this test when a bacterial infection occurs, we could in time determine what levels not to allow in our tanks.
4) BOD: the amount of O2 in the water that gets consumed when stored sealed. It's a measure of the digestible compounds in the water and the size of the organism metabolism.
(interestingly 1 and 4 measure a sort of separate subsets of dissolved organics: the yellow compounds aren't usually very digestible and the digestible ones aren't often that yellow)
[/QUOTE]
This is probably too complicated for the average hobbyist to be able to tackle. Certainly it would be problematic for me most likely.
These all correlate somewhat with the overall level of dissolved organic material. Some better than others. But what I find interesting is that all of those markers are strongly decreased by treatment with GAC.

Would upping the amount and frequency of GAC be more helpful than say ozone or UV for seahorse water remediation? I don't know - but I know it removes a bunch of the above measurable things that get left behind by skimming.

Ozone + ORP gives a nice measurable target and may provide some protection against disease. UV destroys ozone so those probably won't play well together. But I think either ozone or UV would work well with GAC.
GAC used IS recommended to the hobby, along with skimming. (As Randy has mentioned that not all DOs are skimmable) but we still don't know how much for how long without some testing, and the big question I always get is how to tell when the GAC has exhausted and returning things back into the water column. I don't have an answer for that.
Again, thank you for taking time to help.
Now to do more searching....
 
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Randy Holmes-Farley

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Does anyone know if this test kit works in saltwater?

Hanna Free Chlorine Test Kit HI3831F​


It would be highly unusual to have much chlorine in marine aquarium water. What do you want to use it for?
 
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rayjay

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It would be highly unusual to have much chlorine in marine aquarium water. What do you want to use it for?
In post #64 just after your last post here, taricha in point #3 said "Chlorine demand - bleach will react with organic N compounds like proteins and amino acids and so a free chlorine test (cheap hanna test kits) can show you how much bleach your tank water can consume."
My old brain is thinking, that IF we can establish a relationship to know how much chlorine the tank can consume of organic N compounds, perhaps there is a relationship to all DO and we can use the data to somewhat know where the tank's water stands with respect to causing seahorse bacterial infections.
Up until now we've believed it to be caused by increasing DO levels, but you have called that into question so my thoughts are that if we can find a way to test for something and relate it to DO levels it could work for us.
We already know that seahorse bacterial infections are rare when we keep DO from rising so even if it is NOT actually DOs causing the bacteria in increase and affect the seahorses, something that can approximate a DO test easily and economically would be tremendous benefit to the hobby.
Not being chemically savvy, I'm thinking that if the test shows it can consume high levels of chlorine then it means the organic N compounds are high but if only small levels can be consumed then levels are low.
Now if there IS a relationship between organic N compounds and DO then this test may be something we can work with as its economical enough and easy enough for hobbyists to use that we might be able to work out a set of data to eventually find limits that are meaningful.
If a hobbyist can start off testing soon after the seahorses are added it will establish a baseline. If a seahorse bacterial infection occurs they can test again to establish a limit that is too high.
Compiling data from many hobbyists could give us a better idea then on what a dangerous point would be so we could automatically upgrade our DO protocols that we know do fix the problem, even if it isn't DO that IS the problem.
Forgive me if this doesn't make sense but I live with Mild Cognitive Impairment and while it's not severe yet it still makes it hard for me to think things out, especially when it's something like chemistry involved.
 

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The chlorine demand test is a measure of some types of organic matter. If you choose to try the method, I’d look for a published protocol that tells exactly how much to add and how to measure it.
 

taricha

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Does anyone know if this test kit works in saltwater?

Hanna Free Chlorine Test Kit HI3831F​

https://www.hannainst.com/hi93701-01-free-chlorine-reagents-100-tests.html

@Dan_P and I have messed around with chlorine demand in tank water using these hanna reagents.

Dan was able to use it to give some clues about when he should change his GAC.
https://www.reef2reef.com/threads/monitoring-organic-carbon-with-bleach.552407/

he could probably comment on if or how he would modify what he did, or if he thinks the chlorine demand could fit this purpose.
 

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https://www.hannainst.com/hi93701-01-free-chlorine-reagents-100-tests.html

@Dan_P and I have messed around with chlorine demand in tank water using these hanna reagents.

Dan was able to use it to give some clues about when he should change his GAC.
https://www.reef2reef.com/threads/monitoring-organic-carbon-with-bleach.552407/

he could probably comment on if or how he would modify what he did, or if he thinks the chlorine demand could fit this purpose.
Measuring chlorine demand means determining how much free chlorine is consumed by a sample of water and serves an an indicator of water purity. Chlorine break point is another method of using chlorine consumption to determine water purity.

Chlorine reacts with many but not all organic molecules. making a chlorine demand measurement a relative measurement of water purity but not a replacement for a total organic carbon measurement. Also, not all molecules react with chlorine at the same rate. Molecules with a basic nitrogen are among the fastest reacting molecules, reactions requiring only minutes. Ammonia, amino acids and protein are examples of these fact reactors. Everything else reacts more slowly. To develop how long a sample reacts before testing it for free chlorine demand requires some trial and error experiments with samples of “good” and “bad” water to determine an optimum reaction time. That’s the tricky part because good vs bad is relative and reference samples can’t be made so easily. I used free chlorine demand as a trending tool, watching how it changed over time. I assumed more chlorine demand meant more organics in the water, but that is about all I dared to conclude. If I had also measured ammonia levels, I could have said something about the demand being related or not related to the presence of free amino groups, i.e., organic nitrogen + ammonia, but that’s on the back burner. If you would like to give free chlorine demand a try, here is the method I used.

The water sample is placed in a clean Hanna vial and a fixed amount of bleach solution is added. The vial is capped immediately, gently mixed and allowed to stand for 3 minutes ( or 1 minute or six minutes, whatever you determined is right for you). Then test for free chlorine. You will need to know the concentration of the bleach solution to calculate the amount consumed. The calculated chlorine demand is a relative value unless you determine the free chlorine demand of pure seawater. There could be inorganic species that consume a little free chlorine.

I would be happy to answer any questions or help you develop a method.

Dan
 
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Thank you again taricha and Dan.
At the moment, this free chlorine testing appears to give us the best chance of developing a way to know when seahorse system water is more likely to cause bacterial infections in seahorses, regardless of whether or not DO is the actual trigger.
Hopefully our community can be up to the task.
 
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Well, I've gone ahead and ordered a test kit. Next will be to try and develop a protocol that may give me data I need.
To start off, I'll use unused Instant Ocean salt water mixed to s.g. 1.023 and do tests with varying amounts of bleach for varying time periods. Hopefully I'll come up with something satisfactory so I can move on to testing actual aquarium water.
I have NoName 4%, Clorox 8.25% and pool chlorine 12% but I suspect the 12% will be too strong.
Dan P, in your trials, how much of what strength bleach did you use? I could use that as my starting point.
 
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@Randy Holmes-Farley my go to for organics in the lab is TGA, can you think of a way to get the sensitivity you'd need for a reef sample at home?

To me, TGA means thermal gravimetric analysis, which doesn't seem easy to interpret for a seawater sample with ppm levels of mixed organics. Is that what you mean?

TGA on seawater even without organics will be complicated as different materials precipitate and then dehydrate at different temperatures as the temperature rises. Loss of water from carbonate to hydroxide and then to oxide might get confounded with organic degradation, for example. The confounding would include both a mass loss and a CO2 release, if you were tracking gases by MS.
 

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I'm curious as to how many reef hobbyists you think would be set up to do TGA testing?

None. It is a sophisticated lab test. I presume he has one at his job.


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Well, I've gone ahead and ordered a test kit. Next will be to try and develop a protocol that may give me data I need.
To start off, I'll use unused Instant Ocean salt water mixed to s.g. 1.023 and do tests with varying amounts of bleach for varying time periods. Hopefully I'll come up with something satisfactory so I can move on to testing actual aquarium water.
I have NoName 4%, Clorox 8.25% and pool chlorine 12% but I suspect the 12% will be too strong.
Dan P, in your trials, how much of what strength bleach did you use? I could use that as my starting point.
If I recall correctly, my stock was around 100 ppm so that 0.1 mL of stock solution added to a 10 mL sample was around 1ppm bleach.
 

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Too late to edit my post #73.
I asked Dan P how much at what strength bleach he used but I meant to put down HOW LONG and what strength bleach as I assume volume is a consistent measure each test.
I would look at 1 minute and 5 minute reaction times.
 

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