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Ryan Willden 
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 Topic: Sudden Tang Death Syndrome STDS?
Posted: September 19 2003 at 9:14am |
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I am curious to hear what some of your experiences have been about keeping tangs... I'm wondering if there is some type of a "Sudden Tang Death Syndrome" (STDS) that I don't know about, or if I'm doing/not doing something that I should be to keep them alive.
I bought a healthy Yellow Tang about 3 months ago. He was large (2" tall) and seemed very comfortable in my 80G tank. He was one of two tangs. The other is a regal(blue) tang. The blue tang has been in my tank over a year and has done fine (though he is smaller than most of the tangs that have "visited" my tank.) Yesterday, I noticed my Yellow Tang was sick. He was cowering in a corner of my tank. This morning, I found him dead. I have not been able to keep any other tangs in my tank for long periods of time in the past either (Yellow, Sailfin, Naso.) I know I will probably get flamed responses about tank size, but I know tons of other people with tangs in the same size and even smaller tanks that do well, so I don't know if I buy that excuse.
What should I be looking at? Water params all test normal, except for pH which has a tendency to drop to around 7.5 since discontinuing the use of my Kalk Reactor.
Could there be low levels of Oxygen in my tank that affect only larger fish such as tangs? Does low oxygenation reflect low pH or vice versa? Does pH have an affect on tang health? Would placing a fan in my tank stand help?
There were no physical indicators of my tangs health dropping. No Physical sign of parasites, etc. One day he was fine, and the next day, he was "cowering" in the corner. He was breathing normal, etc. He ate fine the day before, and the next day he would not eat. Flake, brine, and occasional nori were his regular diet.
The only "changes" that were made, is that two days prior to his death, I propogated several pieces of Colt Coral in the tank. Could chemical excretions released while cutting the colt cause this type of a problem? If so, why didn't it affect the other fish in my tank?
I don't know where else to go with this, so feel free to ask questions, or make suggestions. I'm going to take a large sample of my water to an LFS today and have it thoroughly tested.
Thanks,
Ryan
Edited by Ryan Willden
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Illsolutions
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Posted: September 19 2003 at 7:05pm |
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I`ve never heard of (stds). Did you make that up or read it in a book or something? did you inspect the fish for any wounds from your other tangs? How many other fish are in the tank? Low ph can cause stress. 7.5 is low but not super low. i`ve seen stuff live in worse! stress usually doesnt kill. normaly when a fish is stressed it will usually die of ich or something like that after a few days. Low oxygen will help lower your ph.....Of course Big fish are goning to require more oxygen. there bigger, there lungs are bigger, there body mass, etc. in a low oxygen case big fish will probbably go first. Cladiella is a very noxious coral to sps. i dont know about fish but if you did it to a large amount it could probbalby freak some stuff out including a tang. did your protein skimmer freak out when you fragged it? let me know!
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Ryan Willden
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Posted: September 19 2003 at 9:31pm |
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I made STDS up... (So if it becomes popular, I want the royalties...) It didn't have wounds, stress, or anything else from any other tangs, because I don't have other tangs it would compete with. That's part of my problem... No other tangs. I don't have a high bioload, or a lot of fish. It didn't show signs of stress at all. No Ich, strange behavior, etc. Protein skimmer didn't even flinch at the colt coral excretion.
Let me put it this way, there was nothing to indicate, or predict it's death. It just got sick one day, and died the next. Hence my coining the phrase STDS.
Thanks for your response.
Edited by Ryan Willden
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Mark Peterson
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Posted: September 20 2003 at 6:07am |
 Ryan Willden wrote:
Could there be low levels of Oxygen in my tank that affect only larger fish such as tangs? Does low oxygenation reflect low pH or vice versa? Does pH have an affect on tang health? Would placing a fan in my tank stand help? |
If my experience is any help, I offer it here.
I could not keep Tangs alive until I started up the RDP Refugia. The conclusion I arrived at was that Tang death was due to low nightime pH. I have all this in an article available via email ( [email protected]) if you want to read it. I call it an article because it was published in a magazine called Marine Fish Monthly.
It is also very possible that your Tang died of natural causes. To determine that, someone more experienced than I would have to do an autopsy! So it may have been out of your control. But let's look at what is in your control. Let's see about pH.
According to Jon Finch's presentation pH is a function of the hydrogen ion. I'm not a chemist, I only find them for companies, but I do know that when Oxygen (O2) is abundant in the water as a gas and Carbon Dioxide (CO2) gas is at a lower level, the pH level stays at a healthy 8.1 - 8.5 for saltwater.
When there is too much bioload (animal and plant respiration and biowaste oxidizing or breaking down) the O2 can easily be used up faster than it can enter the water. This use of O2 for the breakdown/oxidation of biowaste carries the term of measurement called re-dox, as I recall.
Improving the re-dox &/or O2 level in the tank can be accomplished in several ways; an airstone, a skimmer, water movement at the surface and algal or plant growth.
The amount of surface area exposed to the atmosphere is critical and a process called "gas exchange" occurs there and in the bubbles created by the airstone and skimmer. Gas exchange equalizes the differences in concentration of gases between the water and the air at the air/water interface. Water at the bottom of the tank is not affected by the gas exchange process! That's why circulation of water to the surface is very important (as well as circulation of air in a restrictive aquarium hood).
Algae as an oxygenator is a funny thing. You probably know that photosynthesis in plants produces oxygen and uses CO2. Because it is a function of light energy, photosynthesis actually slows or completely stops at night. Interestingly, the plant tissue still needs O2 at night, but since it cannot get it from the Photosynthesis process, it grabs O2 from the water. The animals in the tank are also continuing to use O2 so at night there is an increased demand for O2; or perhaps more accuratly stated: there is a decreased supply of O2 at night. And the only place more O2 can come from at night is the gas exchange process at the water surface and bubbles from the skimmer or airstone. Few people have a simple airstone in their Reef Aquarium but it's not a bad idea, at least until other means can be acquired!
Thank goodness for John Walsh proposing the Reverse Daylight Photosynthesis sump/refugia! Personally, I believe the RDP Refugia is a very important and useful component of a longterm Marine aquarium. Besides adding O2 from algae growth at night, it filters the water as an algae scrubber and it grows critters that filter and feed the tank.
As a side note, most people have trouble keeping Regal/Blue/Hippo Tangs. if yours is well, please don't think that you are doing anything wrong. But improvement is always possible. 
[email protected]
Edited by Mark Peterson
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Suzy
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Posted: September 20 2003 at 7:04am |
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Ryan, did I read the fish was not breathing quickly before it's demise? If it was an o2/c02 issue, you would have noticed a labored breathing pattern. If he is struggling to breathe in the night, then when am comes, he is recovering.....I think that would have happened the first night.... Your tank can never have too much air exchange,though. Stick a power in the bottom of the tank pointed up. You can hide it behind your rock. Adding an airstone will push/pull the h2o up, but I don't think those little bubbles are as effective. Put your hand in to feel the flow. Some people think the bubblers add o2. They really just help move the water to the surface where o2 can be sucked in and co2 pushed out (osmosis).....
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Ryan Willden
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Posted: September 20 2003 at 8:27am |
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Mark, wow... Thanks! That all made a lot of sense. The only thing that I'm a little hazy on, is that I also use an RDP Sump/Refugium with lots of algae and stuff growing in it. While I'm thinking about it though, the growth of that refugium has not been as substantial as when I was using a 6500K PC bulb, and for 7-8 months I have been using an actinic only bulb. Is there a chance that the algae is not growing under the wavelengths provided by such a blue bulb? Other than that, the day I found the tang sick, I placed airstones in my main tank, and placed a fan over the sump, hoping that if O2 was an issue, it would help him out. It was probably too late for that measure, as I monitored the pH after doing so, and it did not raise any. Anyway, I have been curious what correlation there was between pH and Oxygen since Jfinch mentioned he was using a fan in his sump at night to help maintain pH levels. He did this by blowing the air over the top of his water. I can only guess my problem is related...
Suzy, the Tang seemed to have an almost slowed, or normal breathing pattern, but not heavy, or fast at all. I think I'll try your powerhead idea...
I hope I'm on the right track here, but everything points to oxygenation from what I've heard here. If anyone else has any other ideas, please let me know.
Interesting though if this condition we are discussing is accurate, then STDS or Sudden Tang Death Syndrome would be an appropriate term for it. SIDS or Sudden Infant Death Syndrome in babies is caused by a lack of oxygen, or hypoxia... Interesting.
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Marcus
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Posted: September 20 2003 at 8:57am |
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I do not think that 7.5 is dangerously low by itself, but if the change from 8.X to 7.5 to too quick then that could be the culprit.
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Mark Peterson
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Posted: September 20 2003 at 11:16am |
Ryan asked, "Is there a chance that the algae is not growing under the wavelengths provided by such a blue bulb?"
Most certainly! Definitely! Yes! The algae you want to grow should have brite white light(Home Depot Lights of America PC) or plant growth fluorescent illumination or any kind of bright white light you have available even incandescent, except that it's so hot for the amount of light energy.
I would bet that is a big part of the problem, yet it surprised me that increasing aeration did not increase the pH. Test your pH tester by testing at 5AM or before dawn and again at 5PM to see what kind of difference exists, what kind of swing you are getting and what kind of numbers it comes back with. Realize too, that by the time water reaches the LFS, pH of the sample increases.
I agree with Marcus. The pH swing is the most dangerous thing leading to stress of the entire tank.
FYI-The Bangerter tank on the Reef Tour has the same 2 32 watt NO fluorescents as when we started it 3 years ago and it still grows grape caulerpa like crazy. I have to harvest it every two months because it fills the sump! Actually it should be harvested more frequently. I recommend harvesting no more than a third of total bulk at one time, otherwise other algae like hair algae can get a foothold. It gets a foothold because of the change in available nutrients and can start to get out of control. It really is time for me to change those tubes! 
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Ryan Willden
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Posted: September 20 2003 at 2:49pm |
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Here's an update... The pH was actually not even close to 7.5... I took a water sample to an LFS and had it tested. It was 8.1 from the test kit at the lfs and the reading from my Meter when I removed the water from my tank read 7.6 So I'm guessing my meter needs to be recalibrated. I switched the bulb out with a 50/50 7100K/12,000K bulb, and hopefully that will help.
So, I guess that leaves pH out since there was no swing in the pH (Although wrong, it read a steady 7.6-7.6) but I'm still wondering about O2...
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jfinch
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Posted: September 20 2003 at 6:19pm |
(I'm sure you saw my post about Borax for pH calibration)
I don't know why your tang's are dieing... but here's a small treaties on gas absorbtion.
O2 does not effect pH. CO2 does effect pH. The O2 and CO2 are at constant levels in the atmosphere. This is 20% O2 (200,000 ppm) and 350 ppm CO2. The O2 and CO2 in your tank water is always trying to be in equalibrium with the gases in the atmosphere. Equalibrium is approx. 9 ppm O2 and 0.5 ppm CO2 dissolved in the water. The reason that they might not be at those levels are disscussed in the above posts. All gas exchange occurs at the gas/water interface. Doesn't really matter if it's a bubble or water surface. Increasing this surface area will speed up gas absorbtion/deabsorbtion. Skimmers, airstones or power heads pointed upwards all help to do this. I tested the CO2 in my basement at 600 ppm. That's almost double what the average global level is (350 ppm). This has the effect of making my pH about 0.1 to 0.05 lower then it would be if my tank was located on my back porch. I added the fan to my sump to help push old stale air (could be higher then the measured 600 ppm, I didn't check it) out of the stand to be replaced with "fresh" basement air. I think it's helped. It's not probable that O2 levels could be low in your house... you'd most likely go to sleep and not wake up . If there's any question regarding O2 levels, increase the water/air surface area!
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Marcus
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Posted: September 20 2003 at 6:38pm |
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Jon, reading your posts makes me want to go sit in on some college chem classes. How did you test the CO2 in your basement?
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jfinch
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Posted: September 20 2003 at 6:52pm |
Jon, reading your posts makes me want to go sit in on some college chem classes.
You might want to rethink that... chemistry's not all glamour and girls 
How did you test the CO2 in your basement?
I used a portable combustion analyzer from work.
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Ryan Willden
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Posted: September 20 2003 at 7:06pm |
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Jon, thanks... That helps. I didn't think the O2 levels in my house were low, just my tank. But I added a powerhead in my refugium, and an airstone to my sump. Maybe it'll help, maybe it won't... Thanks for your responses.
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GonZo
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Posted: September 20 2003 at 10:08pm |
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Jon - When you took your CO2 readings at home I thought you were going to add some house plants to help. Did you end up just with the fans or did you add plants as well?
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Cortney (West Jordan)
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Marcus
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Posted: September 20 2003 at 11:04pm |
Jon, I don't need any glamour and I already got the girl. 
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Mark Peterson
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Posted: September 21 2003 at 1:28pm |
Speaking for myself as well as others, A little knowledge can be a dangerous thing.
Ryan, It's great to know that your pH is 8.1, but I wonder if there was a swing down to 7.8 by 5AM! Before you installed the new light, did you check it before dawn, before the lights came on? That was where my problem occurred. Have you read my article?
Jon, You said that gases are constant in the atmosphere, but indicated that they are not of the same ratio in our homes. In your home, what gas was lower because CO2 was higher?
It may be extrapolated then, that in the aquarium, gases are also not of the same level as the atmosphere!
Question for Jon and the forum: Is the action of gases the same in water as in the atmosphere? I am wondering if water has an affinity to one gas over another.I have heard that an overabundance of CO2 may push O2 out of the way or at least not allow it to enter the water from the atmosphere (the air/water interface) until a CO2 molecule is released. If this is accurate, it means that when CO2 is higher than normal, O2 is lower than normal. This could cause two problems, lower pH and more difficulty breathing! That = stress which eventually leads to death! Any opinions on this?
What problems does a low O2 level create 1)in our home and 2) in our tank?
Now my mind is racing!  Evidently it isn't that easy for gases to move through water since the interface is so important. This means to me that moving lots of water to the interface is extremely important. I wonder if water at the interface, has a significantly higher pH and higher O2 than deeper water. And if a tank has minimal circulation, is the bottom water a lower pH and starved for O2?
The oceans depths don't see the interface, so how does that effect pH? And how about pH buffering capacity. Does the ocean have it and our tanks lack it?
Has someone with a pH meter ever moved it around the tank to get readings from the bottom corners, for instance. Has anyone pushed it into their DSB and let it sit for a couple days to see what the pH is down there?
Edited by Mark Peterson
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Suzy
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Posted: September 21 2003 at 4:39pm |
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It's an osmosis thing, right?
You really can't have low O2 in your house. If you sealed your house with plastic wrap, maybe! Someone asked during Jon's lecture about our elevation affecting the O2. It's kind of a misconseption about the O2 being different at different altitudes. It's always 21% of our atmosphere. The only thing that changes is the pressure.
You can have low O2 in your tank if you have a significant bioload using O2 and producing C02. In the ocean, the pH would be relatively stable because of H2O motion, osmosis and bioload. I don't think the conditions of a particular area would allow o2 consuming organisms to thrive where there wasn't enough o2. I mean, the population would coorelate to the amount of o2 there was to use ......
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Suzy
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Posted: September 21 2003 at 4:54pm |
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Wait! I forgot to mention! Rob is the King o' Gases! Not because he has it! 'cause he is a RESPIRATORY Therapist! He knows gas!
Jon, is the change from 350 ppm to 600 ppm significant? If you put that in a percent, would the number change? PPM is parts per million, right? Atmospheric O2 is 21%, nitrogen is the most, where is Co2?
BTW, it isn't low O2 that makes people go nightsy-night, it's high Co2, right? We always see people in the ER that have malfunctioing heaters in the winter...Sometimes they don't make it to the hospital, though. Does everybody have a C02 detector?
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jfinch
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Posted: September 21 2003 at 8:32pm |
hmm, this might be an easier topic to discuss in person since there's lots to discuss, but I'll try here...
Cortney, I think plants would help to consume ambient household CO2... but they die on me .
Jon, You said that gases are constant in the atmosphere, but indicated that they are not of the same ratio in our homes. In your home, what gas was lower because CO2 was higher?
I can only speak for my home, but if you live in a very well insulated home with the doors and windows closed, central air and/or heater it's probably the same for you. The elevated CO2 came from respiration (me and my family) and/or combustion (from the heater) so I would assume that the O2 was lower due to this. But it's only lower by approx. 300 - 400 ppm from a starting point of 200,000 (or 210,000 ppm per Suzy's numbers). That's a drop in the bucket and not really detectable by instrument or breathing humans.
It may be extrapolated then, that in the aquarium, gases are also not of the same level as the atmosphere!
Do you mean ratio rather then level? There will always be less "gas" in the water then in the atmosphere, otherwise the water will be atmosphere . Also they won't necessarily be at the same ratio, even at equalibrium due to Henry's Law (see below).
Question for Jon and the forum: Is the action of gases the same in water as in the atmosphere? I am wondering if water has an affinity to one gas over another.I have heard that an overabundance of CO2 may push O2 out of the way or at least not allow it to enter the water from the atmosphere (the air/water interface) until a CO2 molecule is released. If this is accurate, it means that when CO2 is higher than normal, O2 is lower than normal. This could cause two problems, lower pH and more difficulty breathing! That = stress which eventually leads to death! Any opinions on this?
The solubility of a gas into a liquid is described by Henry's Law:
Xgas = (Ha)(Ygas)
Xgas is the concentration of said gas in the liquid phase
Ha is the Henrys Law constant for said gas
Ygas is the concentration of said gas in the gas phase (i.e. partial pressure)
The Henry's Law constant is different for every gas and liquid. It is only dependent on liquid temperature, there is no dependance on other gasses dissolved in the liquid as far as I know. The constant for CO2 in water is 25 times larger then it is for O2 in water. That means that CO2 is 25 times more soluble! So in a nutshell, I don't think CO2 and O2 levels in water effect each other. But if you're having problems with CO2 levels due to poor gas exchange you could very likely have problems with O2 too.
Evidently it isn't that easy for gases to move through water since the interface is so important. This means to me that moving lots of water to the interface is extremely important. I wonder if water at the interface, has a significantly higher pH and higher O2 than deeper water. And if a tank has minimal circulation, is the bottom water a lower pH and starved for O2?
The oceans depths don't see the interface, so how does that effect pH? And how about pH buffering capacity. Does the ocean have it and our tanks lack it?
Has someone with a pH meter ever moved it around the tank to get readings from the bottom corners, for instance. Has anyone pushed it into their DSB and let it sit for a couple days to see what the pH is down there?
I think those are very deep questions. The ocean does have varying levels of CO2, alkalinity and O2 as a function of depth. Maybe Adam or someone else might be able to better explain oceanography better then me. Our tanks (if you use an alkalinity supplement) have more buffering capacity then the ocean. I would bet money that a pH meter stuck down into a DSB will read low (mid/low 7s) if there is any denitrification occuring in the bed.
Suzy said:
is the change from 350 ppm to 600 ppm significant? If you put that in a percent, would the number change? PPM is parts per million, right? Atmospheric O2 is 21%, nitrogen is the most, where is Co2?
BTW, it isn't low O2 that makes people go nightsy-night, it's high Co2, right? We always see people in the ER that have malfunctioing heaters in the winter...Sometimes they don't make it to the hospital, though. Does everybody have a C02 detector?
I don't have the numbers in front of me, but I do know my tank water at the end of the day when CO2 levels in the tank should be the lowest will increase by 0.1 to 0.05 pH when taken outdoors and bubbled. That to me means the elevated CO2 levels are significant if you feel that pH depression is significant.
Normal atmosphere contains:
79% N2
21% O2
everything else is just a trace. For example CO2 is 0.035%.
Low O2 levels (I think below about 17%) can cause suffocation. It happens more often then it should in my line of work. We often purge vessels with pure N2. If someone inadvertantly enters this vessel they die. This happens about every year somewhere in the world  . Elevated CO (or CO2) can cause death too due to "poisoning". I have a CO monitor in the furnace room, but not CO2.
Edited by jfinch
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Adam Blundell
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Posted: September 22 2003 at 8:53am |
jfinch wrote:
Maybe Adam or someone else might be able to better explain oceanography better then me. Our tanks (if you use an alkalinity supplement) have more buffering capacity then the ocean. |
Well I don't have much to say about this. In general the ocean is very well buffered, and supersaturated with calcium. In most reef systems O2 levels and CO2 levels tend to not be an issue, and are not discussed much. I believe that O2 is NOT a limiting factor in nearly all marine systems. What is of concern (for the future) is global warming and CO2 accumulation. There is fear that the water temperature will rise and both O2 and CO2 will be less soluble and come out of solution. And as Jon said CO2 is 25 times more soluble, so the real difference will be a decrease in O2 levels. I'm not sure how much of a problem this will really be, but it is an upcoming issue.
Adam
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