# Unstable PH.



## kfig7 (Nov 24, 2008)

I noticed in the last few days that my ph goes from about 7.8-8.0 in the morning to about 8.4 at night. It's driving me crazy. Is there anything I can do about this? My well water tests at around 7.8 and I am also using crushed coral in both of my FX5's. In the past I have always used Seachem malawi buffer I figured I'd try the crushed coral instead. Should I go back to using the buffer?


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## prov356 (Sep 20, 2006)

> Is there anything I can do about this?


I wouldn't. Trying to use commercial buffers to zero in on some specific pH value is of little benefit. As 
long as it's in an acceptable range, which it is, I wouldn't worry about the variance between morning and 
night.

But as to why it's doing this, I know CO2 can have an affect like this on pH. Are there plants in the tank? 
I suppose even a heavy algae growth possibly could be the cause as well, even if no plants.


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## zugbug (Dec 12, 2005)

But as to why it's doing this, I know CO2 can have an affect like this on pH. Are there plants in the tank? 
I suppose even a heavy algae growth possibly could be the cause as well, even if no plants.

your best defense in pH stability is buffering. As far as CO2, it can have an affect on pH but it would drive the pH down due to the formation of Carbonic acid when the CO2 is combined with the water. But again this would only be a problem without any buffering in the water.


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## Lively (Jan 13, 2009)

prov356 said:


> > Is there anything I can do about this?
> 
> 
> I wouldn't. Trying to use commercial buffers to zero in on some specific pH value is of little benefit. As
> ...


I agree 100%.

If you want to read something long, boring and filled with scientific jargon http://jeb.biologists.org/cgi/reprint/19/1/92.pdf Basically, it shows how the ph fluctuates in freshwater streams and ponds.


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## boredatwork (Sep 14, 2007)

That is a relatively big fluctuation though, especially if there is crushed coral already in the tank. I do agree the behavior seems consistent with CO2 produced by plants during the day and then absorbed at night. But I would think it would have to be a pretty heavily planted tank, or have some kind of CO2 source external to the tank. If I wasn't lazy I would find a link to the CO2 vs pH table. If you are less lazy than I am you can try to find it. It might help give you an idea of whether or not that that is a legitimate cause.

Regardless of the cause, I would disagree about not using a buffer. The generic advice is to leave pH alone because its better to have it stable blah blah blah. In this case, for that very same reason, a buffer would be useful. Personally, I think buffers are given a bad rap for a lot of the wrong reasons. In this case, regardless of the actual pH number, a daily fluctuation of pH is easily avoidable at little to no cost.


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## Lively (Jan 13, 2009)

boredatwork said:


> Regardless of the cause, I would disagree about not using a buffer. The generic advice is to leave pH alone because its better to have it stable blah blah blah. In this case, for that very same reason, a buffer would be useful. Personally, I think buffers are given a bad rap for a lot of the wrong reasons. In this case, regardless of the actual pH number, a daily fluctuation of pH is easily avoidable at little to no cost.


It has only been doing this for the past few days according kfig7 - why start a buffer when it is could be a transient problem? Maybe an algae bloom - who knows. I'm of the mindset to allow a tank to balance itself out on its own - if at all possibe and not to the detriment of the fish. According to the article I linked, fish in the wild are subjected to much wider varients in ph daily.


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## zugbug (Dec 12, 2005)

boredatwork said:


> That is a relatively big fluctuation though, especially if there is crushed coral already in the tank. I do agree the behavior seems consistent with CO2 produced by plants during the day and then absorbed at night. But I would think it would have to be a pretty heavily planted tank, or have some kind of CO2 source external to the tank. If I wasn't lazy I would find a link to the CO2 vs pH table. If you are less lazy than I am you can try to find it. It might help give you an idea of whether or not that that is a legitimate cause.
> 
> Regardless of the cause, I would disagree about not using a buffer. The generic advice is to leave pH alone because its better to have it stable blah blah blah. In this case, for that very same reason, a buffer would be useful. Personally, I think buffers are given a bad rap for a lot of the wrong reasons. In this case, regardless of the actual pH number, a daily fluctuation of pH is easily avoidable at little to no cost.


Plants do not create CO2 they consume it. CO2 is injected into planted tanks to the benefit of plants. 
We can beat a dead horse or kfig7 can buffer his/her tank which is_* always *_a good thing and then check pH's again at the same intervals.

As an FYI..... in absolutly pure water CO2 in water can depress the pH from 7.0-5.5 with as little as 1ppm of CO2


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## prov356 (Sep 20, 2006)

Guys, nowhere do I see a current KH value stated. How can anyone recommend he start buffering 
when for all we know, buffers are plentiful? A bounce like he's experiencing, I'm guessing, is not 
caused by a lack of buffers. My pH bounces like that out of the tap when buffers are plenty enough 
that it should be stable. There are other reasons.

And I'm not bad rapping buffers. They're just not always needed. If pH stability is a problem due to low 
buffers, then they should definitely be used. But if buffers are adequate from the tap, and are 
replenished via water changes before going dangerously low, then adding them does nothing more to 
stabilize pH than the ones that were already there. A KH of 5 stabilizes pH as well as a KH of 10. 
Adding them in that situation may up the pH, but that's all.


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## zugbug (Dec 12, 2005)

Lively said:


> prov356 said:
> 
> 
> > > Is there anything I can do about this?
> ...


wow . That study was done in 1937 and published in 1942!

And if you read the entire paper it contradicts your point.. the conclusions are that yes there is pH fluctuation from day to night based on dissolved O2 consumption but the study showed that bodies of water with the higher alkalinity (buffering) showed less fluctuation in pH values.


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## prov356 (Sep 20, 2006)

I should add that the opinions I express are based simply on my experience. I used to buffer to +10, and 
I maintained a pH of 8.2. Now I don't add buffers at all. My KH out of the tap is aobut 5 and my pH once 
settled is about 7.8. And that's now where my tank pH stays. It wasn't that difficult to do, but as I added 
more tanks and will be soon adding even more tanks, and they all can vary water change wise, it just 
really simplified things for me.


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## boredatwork (Sep 14, 2007)

prov356 said:


> Guys, nowhere do I see a current KH value stated. How can anyone recommend he start buffering when for all we know, buffers are plentiful?


Sometimes we even ignore our own advice. Hopefully no one saw my post in the other thread.


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## boredatwork (Sep 14, 2007)

zugbug said:


> As an FYI..... in absolutly pure water CO2 in water can depress the pH from 7.0-5.5 with as little as 1ppm of CO2


Another reason to know the KH.

By the way, this statement is wrong based on every dissolved CO2 table I could find. Especially if you really meant to say a 7.0-5.5 shift from 1ppm of CO2. 
http://www.thekrib.com/Plants/CO2/khgh.html

That is why I said to look up the table. Unless there is extremely low KH the pH should not fluctuate greatly from plant produced CO2. Which means that if the plants are the cause there is extremely low KH, so a buffer would help.

Again, I agree the KH is the critical piece of information here. Well, that and we don't even if there are plants!! :lol:

Also, regarding fish in the wild. That is not a good piece of information. People also make this same claim regarding temperature fluctuations. Unless this information is combined with their whereabouts during the change then it doesn't matter. In the wild fish aren't obligated to stay put. When changes in the water occur they can move. This is a known behavior with temperature, and I suspect with changes in pH as well.


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## prov356 (Sep 20, 2006)

> Sometimes we even ignore our own advice. Hopefully no one saw my post in the other thread. Embarrassed


Too late, I did see that after this one and was kind of like, huh?? :-? Isn't this the same poster? :lol:


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## Lively (Jan 13, 2009)

boredatwork said:


> Also, regarding fish in the wild. That is not a good piece of information. People also make this same claim regarding temperature fluctuations. Unless this information is combined with their whereabouts during the change then it doesn't matter. In the wild fish aren't obligated to stay put. When changes in the water occur they can move. This is a known behavior with temperature, and I suspect with changes in pH as well.


Two of the tests were in ponds - fish obligated to stay. lol.

But, my point was that in the wild fish do fine with extreme changes. I can almost guarantee that my JD's will spawn soon after a large water change and a temp drop and rise. Apparently it mimics the onset of the rainy season.

However - my biggest reason against buffer at this point is it is a recent development and the swings aren't that massive.

I'm not against buffer, I've done it before.


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## boredatwork (Sep 14, 2007)

Sometimes I too get caught up in the moment. My brain is programmed to argue first, think later.

Or maybe I should say in this post I was illustrating what not to do.

Or maybe I have split personality disorder?


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## Lively (Jan 13, 2009)

boredatwork said:


> Sometimes I too get caught up in the moment. My brain is programmed to argue first, think later.
> 
> Or maybe I should say in this post I was illustrating what not to do.
> 
> Or maybe I have split personality disorder?


ROFL! I had to reprogram mine... I used to be a Mod/Admin thingie at a pretty big site - had to learn not to flame... I was good at flaming... I could argue paint off the wall! lol


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## boredatwork (Sep 14, 2007)

Lively said:


> Two of the tests were in ponds - fish obligated to stay. lol.


Stay in the pond I agree. Stay in the same area that is experiencing pH fluctuations I do not agree. Read the article again. He evens talks about stratified changes in the pond. So again, I dont think this piece of information is applicable at all.



Lively said:


> But, my point was that in the wild fish do fine with extreme changes.


Again, inconclusive evidence.



Lively said:


> I can almost guarantee that my JD's will spawn soon after a large water change and a temp drop and rise. Apparently it mimics the onset of the rainy season.


I am not disagreeing with this assertion at all. I never once said a fluctuation matters. I am saying pointing to measurements taken from a pond means nothing.



Lively said:


> However - my biggest reason against buffer at this point is it is a recent development and the swings aren't that massive.


Even though it may be a recent development to freshwater (I don't even know if that's true) saltwater people can talk all day about buffers. Regardless of the amount of time it has been used as an application there is well documented science behind it. And again, I never said the swings were massive.

What I am saying, (obviously we are talking theoretically since we don't know the specifics of the tank) is that a simple buffer to keep a constant pH is not a big deal. I never said not using it is a bad thing.


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## zugbug (Dec 12, 2005)

boredatwork said:


> zugbug said:
> 
> 
> > As an FYI..... in absolutly pure water CO2 in water can depress the pH from 7.0-5.5 with as little as 1ppm of CO2
> ...


2 things you either didn't read the article or didn't understand it. read the entire article and it explains how C02 is used to lower pH. Have you ever seen a public pool system? They use CO2 to lower pH..

And you are right I did say a shift from 7.0-5.5 with 1ppm of CO2 in _*absolutly pure water*_.

I dont know where you are getting your CO2 tables from but CO2 + H2O = H2CO3 (carbonic acid)

*Here are the highlights of your article:*

If the pH of an aquarium is determined PRIMARILY by the carbonate
buffering system, then the relation of pH and KH and dissolved CO2 is
fixed. * You can change either KH or CO2 to set the pH. An automatic CO2
injection system will measure pH and inject CO2 to lower it if it
exceeds a set point*. In this case KH is fixed. As the CO2 is used by
plants and diffuses into the atmosphere, the pH will rise. The
controller cycles the CO2 on and off to keep the pH around a fixed
value.

The following chart shows dissolved CO2 levels in ppm for a range of
KH and pH values:

degrees KH
2 3 4 5 6
+------------------------
6.6 | 15 23 30 38 46
6.7 | 12 18 24 30 36
6.8 | 9 14 19 24 28
pH 6.9 | 7 12 15 19 23
7.0 | 6 9 12 15 18
7.1 | 5 7 9 12 14
7.2 | 4 6 8 9 11
7.3 | 3 4 6 7 9
7.4 | 2.4 3 5 6 7
7.5 | 1.9 2.5 3.5 5 5
7.6 | 1.5 2 2.5 3 4
7.7 | 1 1.5 2 2.5 3
7.8 | 0.9 1.1 1.5 2 2
7.9 | 0.6 0.9 1 1.2 1.6
8.0 | 0.5 0.7 0.9 1 1.2

Note that typical dissolved CO2 levels in a moderately stocked
aquarium will be in the range of 2-3 ppm. From the chart, it is clear
that almost any carbonate hardness will produce a pH in the mid 7
range unless extra CO2 is added. For a typical planted aquarium,
pH=6.9, KH=4 and CO2=15 ppm is just about ideal.


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## sleepy09 (Jan 15, 2009)

Great reading on this site. =D> opcorn: I ain't sayin nuttin, I am stayin out of it. Yall are over my head in this one.


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## Lively (Jan 13, 2009)

Guess I didn't read it well enough... you're dead on right about the stratified levels. I still think I'm right about fish being able to withstand water variable better than we give them credit for - but agree that the evidence is sketchy and am not willing to test the theory on *my* fish... lol

I have a salt, so yeah I know how impt. buffers are.

I agree that a simple buffer to keep a constant pH is not a big deal, but I don't believe it should be done on a tank that is within normal parms normally. I had an oddity with pH not too long ago. Not sure what caused it - lasted a week and then went away. I did buffer twice - but my tank fixed itself in the end.


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## boredatwork (Sep 14, 2007)

I have no idea what you are talking about. I know CO2 reduces pH in water. I already stated that it would. The table you posted is from the article that I posted that shows that. What I am saying is that I did not find any relevant table that showed a reduction of 7.0 to 5.5 with a change of 1ppm CO2. If you show me that then I will believe you. Until then I don't see how it is relevant and as a result is a waste of time arguing about.

I am saying that based on the CO2/KH/pH tables I found, unless the KH is extremely low for a cichlid tank (and dangerously low in my opinion) the presence of plants or algae should not effect the pH as dramatically as the OP stated. I don't think this should be interpreted as me saying that I don't believe CO2 lowers ph?


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## boredatwork (Sep 14, 2007)

Lively said:


> Guess I didn't read it well enough... you're dead on right about the stratified levels. I still think I'm right about fish being able to withstand water variable better than we give them credit for - but agree that the evidence is sketchy and am not willing to test the theory on *my* fish... lol
> 
> I have a salt, so yeah I know how impt. buffers are.
> 
> I agree that a simple buffer to keep a constant pH is not a big deal, but I don't believe it should be done on a tank that is within normal parms normally. I had an oddity with pH not too long ago. Not sure what caused it - lasted a week and then went away. I did buffer twice - but my tank fixed itself in the end.


I think we have come to full agreement.

After a long discussion with prov on a post a long ago he opened my mind to thinking that pH variation may not be as deadly as everyone makes it out to be. So, withing reason, I don't think pH swings are necessarily "dangerous".

I also agree that buffers are only needed in very specific cases. I use a buffer because my watr out of the tap is 8.6 and then drops to 6.0. So I buffer to 8.3 to keep it consistent. My KH out of the tap is practically 0ppm. But if you have a decent KH then I don't think there is any need to buffer.


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## Lively (Jan 13, 2009)

boredatwork said:


> I think we have come to full agreement.
> 
> After a long discussion with prov on a post a long ago he opened my mind to thinking that pH variation may not be as deadly as everyone makes it out to be. So, withing reason, I don't think pH swings are necessarily "dangerous".
> 
> I also agree that buffers are only needed in very specific cases. I use a buffer because my watr out of the tap is 8.6 and then drops to 6.0. So I buffer to 8.3 to keep it consistent. My KH out of the tap is practically 0ppm. But if you have a decent KH then I don't think there is any need to buffer.


 :thumb: A meeting of the minds...


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## zugbug (Dec 12, 2005)

boredatwork said:


> I have no idea what you are talking about. I know CO2 reduces pH in water. I already stated that it would. The table you posted is from the article that I posted that shows that. What I am saying is that I did not find any relevant table that showed a reduction of 7.0 to 5.5 with a change of 1ppm CO2. If you show me that then I will believe you. Until then I don't see how it is relevant and as a result is a waste of time arguing about.
> 
> I am saying that based on the CO2/KH/pH tables I found, unless the KH is extremely low for a cichlid tank (and dangerously low in my opinion) the presence of plants or algae should not effect the pH as dramatically as the OP stated. I don't think this should be interpreted as me saying that I don't believe CO2 lowers ph?


As I said in *absolutly pure water *such as condensate,(from steam) that is returned to a boiler which is pure water 1ppm of CO2 will lower pH from 7.0 -5.5 look up some tables on condensate in boilers. Pretty basic.


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## sleepy09 (Jan 15, 2009)

Still opcorn:


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## kfig7 (Nov 24, 2008)

Sorry I haven't posted the KH yet. Been really busy and couldn't find my KH test kit anywhere last night. Looks like I will have to go out today and get another.

I did check my PH again last night and it was the same as earlier in the day. 7.8-8.0 so thats a good sign.

Hoping its the same when I check it later today.

Oh and I don't have any plants at all and hardly any algae. So it is definitely not the CO2. I am hoping it just had something to do with the cycle.


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## kfig7 (Nov 24, 2008)

Just checked my KH and it is only 6.

Not as high as I would like it but it should be fine?


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## boredatwork (Sep 14, 2007)

zugbug said:


> As I said in *absolutly pure water *such as condensate,(from steam) that is returned to a boiler which is pure water 1ppm of CO2 will lower pH from 7.0 -5.5 look up some tables on condensate in boilers. Pretty basic.


As I said unless you show evidence of this it is a waste of time. So I did your work for you: 
http://www.districtenergy.org/06CampCon ... _Bloom.pdf Slide 9 shows that in pure water with 0ppm CO2 with a pH of 7.5, adding 1ppm of CO2 will drop the pH to 5.5.

So now that the supporting data has been produced I will spend a few words going off topic for the sake of the general good. I am sure my response will be quite predictable.

What is the value of this information? Of course the answer is none. Some people may see this as innocent, but I don't. This is the kind of thing that actually annoys me - irrelevant information being posted which ultimately causes confusion and dissemination of misinformation. So to me that impact is actually negative rather than neutral. There is no relevance of "pure water" to fish.

I see this quite often. People post irrelevant information that appears to be believable, and I am sure I have been guilty of this. Then others who are not fully familiar with the information discussed will start to use the irrelevant information. I can almost guarantee that someone will come across this thread and see that 1ppm of CO2 will change your pH from 7.5 to 5.5 and they will start posting about what should they do about it since they have a lot of plants or something.

So I think its important to not post irrelevant information.


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## sleepy09 (Jan 15, 2009)

Still opcorn:


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## Lively (Jan 13, 2009)

zugbug said:


> As I said in *absolutly pure water *such as condensate,(from steam) that is returned to a boiler which is pure water 1ppm of CO2 will lower pH from 7.0 -5.5 look up some tables on condensate in boilers. Pretty basic.


I didn't have to go past the first page... you're comparing apples and oranges here. This is an article about boilers! And you had the audacity to ding me for an old article that was on target for FISH! I have to echo boredatwork here, what is your point and what is the value of this information? Are you suggesting that he rig a condensate line and add pure water?


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## zugbug (Dec 12, 2005)

boredatwork said:


> That is a relatively big fluctuation though, especially if there is crushed coral already in the tank. I do agree the behavior seems consistent with CO2 produced by plants during the day and then absorbed at night. But I would think it would have to be a pretty heavily planted tank, or have some kind of CO2 source external to the tank. If I wasn't lazy I would find a link to the CO2 vs pH table. If you are less lazy than I am you can try to find it. It might help give you an idea of whether or not that that is a legitimate cause.
> .


I'm glad you brought up the topic misinformation.... which brings me to your brilliant statement that plants produce CO2. =D> I thought my fish were going to suffocate if I put plants in my tank.

I think if you want you can probably find a table that proves that plants do not produce CO2, I would do it for you but I'm too lazy.


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## zugbug (Dec 12, 2005)

Lively said:


> zugbug said:
> 
> 
> > As I said in *absolutly pure water *such as condensate,(from steam) that is returned to a boiler which is pure water 1ppm of CO2 will lower pH from 7.0 -5.5 look up some tables on condensate in boilers. Pretty basic.
> ...


the point wasn't to ding you if it came across that way sorry. My only point was that CO2 can reduce pH....I only used that as example.


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## prov356 (Sep 20, 2006)

kfig7 said:


> Just checked my KH and it is only 6.
> 
> Not as high as I would like it but it should be fine?


It's enough to stabilize pH at that level. Just monitor it for a few months to ensure that your water 
change routine is keeping it around that level.


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## boredatwork (Sep 14, 2007)

zugbug said:


> boredatwork said:
> 
> 
> > That is a relatively big fluctuation though, especially if there is crushed coral already in the tank. I do agree the behavior seems consistent with CO2 produced by plants during the day and then absorbed at night. But I would think it would have to be a pretty heavily planted tank, or have some kind of CO2 source external to the tank. If I wasn't lazy I would find a link to the CO2 vs pH table. If you are less lazy than I am you can try to find it. It might help give you an idea of whether or not that that is a legitimate cause.
> ...


The problem with that is that I know I made a mistake bye stated it backwards. The difference is I didn't defend it. Like you have been.

Although the funny thing is you probably wouldn't have to look hard enough to find said table.

By the way. I am saying that my apparent dyslexia reversed the order. It would be wrong to say that plants strictly produce CO2. That would be adding to the misinformation. When light is present plants use CO2 by photosynthesis to produce energy (sugar) and O2. However, in the absence of light, plants will use O2 by cellular respiration (similar to humans) to produce energy and CO2. But since plants cannot perform respiration as efficiently as photosynthesis the amount of CO2 produced during cellular respiration is less than the amount consumed during photosynthesis. So over a full 24 hours (or full on-off photo-period) the net CO2 amount is positive.

What does this have to do with the OP? Absolutely nothing, and I am sure that makes some people mad. Luckily the OP started another thread and got some good answers. While I do feel bad about upsetting people, I always try to think about future readers that come across the threads I participate in. When doing a search for a variety of terms this thread will come up, so I think it is important to maintain the integrity of information presented. The main reason I feel this way is because in my early days I was infected multiple times with false information that I came across. Many times the information was from threads that were months, if not years, old.


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## zugbug (Dec 12, 2005)

> The problem with that is that I know I made a mistake bye stated it backwards. The difference is I didn't defend it. Like you have been.


My statement was true if the entire context of the sentence was read.

I was just trying to make a point using an extreme example...and in retrospect a bad example I agree.

I hearby vow to use caution when using examples to avoid confusion.


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