Ph

[chimera]

How quickly does Alk get depleted in peoples tanks each week? Mine dropped heaps in 1 week, kH from 8.5 to 5.2 (also Ca from 420 to 370, Mg from 1350 to 1230) Not sure what my pH is, gotta calibrate my pinpoint again. I gotta up my Ca reactor bubble rate i think to maintain these levels and I'm only at about 60% stocked in corals! What can cause kH to drop so fast?

[lduncan]

Mine drops around 0.8 to 1 dkH every day. That's equivalent to around 13 grams of coral skeleton growth per day, if it all goes into coral growth.

KH can drop from precipitation with calcium (or initiated by iron oxide hydroxides), growth of coral skeletons, but bacteria can be a significant consumer, as it is an easy source of carbon.

[suphew]

I would be lucky if I tested mine every couple of months, if the corals are looking fine I don't stress it to much. Gota love Xenia, looks sad as soon as something is too far off.

[cracker]

I consume 5 superheaped tablespoons of bicarb per week.

Drops from 12KH to 7KH.

Suphew, you must have minimal growth if you dont test for KH.

[wasp]

Layton you seem detirmined to make this another one of these I'm right, you're wrong things.

I can see where you are coming from now, the way i worded the sentence you have a problem with did not make my meaning 100% clear, however I am sure you know what I meant.

Would you have gone to so much trouble to disprove the sentence, if somebody other than me had said it?

However, for your info only, you have missed the point I was trying to make, and to a degree, the point of the graph. Notice on your graph, the tank with the higher alkalinity, at a given Co2, had a higher PH than the tank with the lower alkalinity, but the same Co2. THAT is what is important, and is what I was trying to get across.

To explain further, if you like graphs, check this one

This graph shows the effect of increased alkalinity on pH when leaving the excess carbon dioxide unchanged.

Get it?

Now here is my statement you have a problem with

BUT, the more KH, ( higher dkh number ), the more Co2 there has to be to lower PH.

To make my meaning more clear for you, I could add 4 words on the end, ie, to a certain level. So to get my sentence word perfect for you, I should have correctly said "BUT, the more KH, ( higher dkh number ), the more Co2 there has to be to lower PH to a certain level"

Get it now? This is what the graph shows, and is also confirmed by my quote from Randy in the previous post "The pH of marine aquarium water is intimately tied to the amount of carbon dioxide dissolved in the water. It is also tied to the alkalinity."

If it will make you feel any better & that you have proved something, I will admit my sentence you have found fault with was not worded 100% perfectly, if it had been a legal document.

However I do think everyone except you would have taken it the way I meant it.

So, if we are playing word games, you won

If we are trying to help Fay with her PH, I hope that sentence & in fact that whole post may have been helpful.

As for the argument that followed, word games, academia, and gobbledegook. :lol:

[suphew]

Suphew, you must have minimal growth if you dont test for KH

How does testing make things grow faster?? I have a cal reactor, I tested when I set it up, test every few month to make sure its on track. I sometimes think people change too much in there tanks, esp if they are testing every five minutes

[wasp]

Well Hey look what I found! Someone trying to check their facts on one forum, AFTER they opened their mouth on this one! :lol: :lol:

http://reefcentral.com/forums/showthrea ... did=858930

This, from Randy, will also enlighten, Layton

Quote "The higher the alkalinity the more the tank is buffered against changes in pH due to the addition (or removal) of any acid, including CO2/H2CO3/carbonic acid.

However, there are other factors as well. The buffering provided by bicarbonate/carbonate is greater the higher pH is in the range of 7.5 to 9."

[lduncan]

However, for your info only, you have missed the point I was trying to make, and to a degree, the point of the graph. Notice on your graph, the tank with the higher alkalinity, at a given Co2, had a higher PH than the tank with the lower alkalinity, but the same Co2. THAT is what is important, and is what I was trying to get across.

To explain further, if you like graphs, check this one

This graph shows the effect of increased alkalinity on pH when leaving the excess carbon dioxide unchanged.

Get it?

I got that all the way back on page 2. From what you wrote it seemed like you were saying something else.

The one thing which affects the relationship between KH and pH is CO2.

For example, if you have a buildup of CO2 around your tank, then although your KH may be fine, you may find that pH is lower than normal.

Or if you run a calcium reactor, you may find that pH is lower than it otherwise would be because of excess CO2.

Now here is my statement you have a problem with

You will probably just brush it off as semantics, but that changes the meaning to something different. Something I agree with.

How am I meant to tell what you're writing. I don't make up what I think you said, I go by what you say. I'm not pissing around with word games, nor is it semantics, it's about saying what you mean. If you don't, then how am I meant to know if it's a mistake or not?

Maybe to you, but those equations explain the relationship between CO2 / CO3(2-) / HCO3(-) and pH

[lduncan]

Well Hey look what I found! Someone trying to check their facts on one forum, AFTER they opened their mouth on this one! :lol: :lol:

I've been trying to figure this particular question out. I haven't passed it off as "fact", that's why I asked the question initially. Maybe i've missed something. I'm still unsure, what I said seems to be the case for the ranges of alkalinity tanks run at, from Randy's graph, and the equation.

[Fay]

wasp wrote:While there are some points in favour of running a high KH, be aware a high KH has also been shown in low nutrient systems, to be associated with RTN of SPS corals.

cracker wrote:I consume 5 superheaped tablespoons of bicarb per week.

Drops from 12KH to 7KH.

So Cracker you run your Kh up to 12kh what is your nitrate readings any RTN

[wasp]

Do you think it's been an aweful lot of effort just to split a few hairs Layton?

[wasp]

Well, looks like you should check your facts BEFORE you start silly arguments Layton

I now have absolute proof, I WAS RIGHT THE WHOLE TIME!!!

Both the initial statement I made, and the one I added some words to for your understanding, were both correct.

After trying to find your facts at Reef Central, and presenting your formulas, here is what you asked Randy

Quote Layton "Is this calculation correct (logically at least, Ka values may be wrong)? If so, it's showing me that for two different alkalinity levels if you change the partial pressure of CO2, then the pH drops by the same amount in both cases?"

Randies reply Quote "No, they will not drop by the same amount. Take an extreme, with no alkalinity (no HCO3- or CO3--). The first little bit of CO2 will drop the pH way down, like you'd get in fresh water.

For a small amount of CO2 added, the pH drop is directly proportional to the amount of alkalinity.

I don't know how your equation shows anything about the effect of CO2 on pH. The level of carbonate is not a constant. The higher the alkalinity, the higher the amount of carbonate at any given pH." End quote.

Here are the 2 most interesting parts again :-

No, they will not drop by the same amount.

and:-

I don't know how your equation shows anything about the effect of CO2 on pH

I did wonder why you suddenly backed off telling me I am wrong a few posts ago and insinuated you were "just asking" :lol: Checked the timing and found out it was after Randy told you you were wrong. So all of a sudden you were "just asking" :lol:

I am hoping this will be a lesson to you about your stupid arguments, and also I am tired of you constantly trying to insinuate that I am wrong about this, that, or whatever, when it is obvious, to me anyway, that you often do not have a full grasp of the facts and are simply wanting an argument.

You could have saved yourself some embarrasement if you'd let the whole thing go way back when I said I really did not want an argument, instead of doggedly carrying on.

Do you still think it was worth all the effort you put into trying to split hairs over this?

I am hoping I am going to be able to post on this forum like anyone else now without you always trying to argue everything I say. You have never proved me wrong on anything yet, just ruined lots of threads.

[lduncan]

You know wasp, I was not trying to pass this of fact right from the start. It was a question "are you sure?". Why did I ask the question? Because I had seen this passage:

Myth: A Low KH results in a larger pH swing when adding CO2.

Many people are under the mistaken impression that a low KH results in large pH swings when adding CO2, while raising the KH will result in smaller pH swings. This is not the case. The KH will move the start and end pH values, but the pH swing will be the same for a given level of CO2. You can see this in the chart below, or using the calculation:

Case 1: Assume a KH of 15 degrees, and a starting CO2 level of 4.5ppm, which would result in a pH of 8.0. If we then add CO2, to increase the CO2 level to 28ppm, that would drop the pH down to 7.2, for a pH shift of .8.

Case 2: Assume a KH of just 1.5 degrees, and a starting CO2 level of 4.5ppm, which would result in a pH of 7.0. If we then add CO2, to increase the CO2 level to 28ppm, that would drop the pH down to 6.2, for a pH shift of .8, the exact same as in case 1.

One possible explanation for this myth is that many copies of this pH chart skip some of the higher pH values, for example, jumping from pH 7.4 to a pH of 8.0. If the reader didn't pay careful attention, they might mis-interpret the size of the pH swing. I specifically made sure to include all pH values, between 6 and 8, in steps of .2.

This relationship will break down at extremely low KH levels (below 1 degree), when there isn't enough carbonate to completely buffer the acids present. In that case, the pH can drop quickly and dramatically. But if the KH is 1 degree or higher, then the size of the pH swing when injecting CO2 will be determined only by the amount of CO2 dissolved in the water.

And I wanted to find out if in fact it was correct. I asked you if you could explain it, but there was confusion on what I though, and you thought you were saying. So I wrote some equations. Then asked Randy for his input. He said that the concentration of carbonate is not constant, something which I had missed, but from his graphs it looks as though within a 1 meq range the pH change is pretty close, even when carbonate is factored in.

Layton

[chimera]

JUST TO JUMP IN ON YOUR LOVE/HATE RELATIONSHIP WITH A PH QUESTION...

I have a American Marine pH pinpoint monitor. When I calibrate it, I turn the "7" screw and can calibrate the fluid to 7 ok. However when I turn the "4/10" screw, it only ever hangs around 6.7 - it won't go any higher. Does anyone know if this type of thing happens when the probe is too old and needs replacing or is the "4/10" screw faulty? Its defaintely pH 10 calibration fluid I'm using, Im edging on the unit being faulty otherwise why would the 7 work? Anyone got a pinpoint pH monitor they can confirm???

Cheers

[lduncan]

First i'd triple check the calibration fluid is not contaminated.

Then check the probe (borrow a known working one to try on your unit), but if it's that far out the probe must really be screwed.

If none of that works, then the meter is bung.

If nothing is happening at all (not change at all on the screen) when you turn that screw full range, it's more than likely the meter which is screwed (may be fixable though, especially considering the 7 point seems to work).

Layton

[wasp]

You are still playing word games Layton.

The reality is you thought you had caught me making a small mistake, and then set about going to huge lengths trying to make my statement seem it isn't correct.

Here is an example of you doing it.

So it seems that this isn't correct in the case of CO2. So it's kind of unusual, but at the same time important as CO2 is the acid which often effects this equilibrium, and has potential to skew it.Layton

Note you said So it seems that this isn't correct in the case of CO2

In fact, you were incorrect.

You then further demonstrated your lack of understanding by attempting to write chemical formulae to prove your point. In terms of demonstrating your point the chemical formulae were flawed and did not make sense.

I don't really wish to go on about this any more in fact i wish the whole thing had not happened. I'm just saying if only you would check your facts before you start these stupid arguments, none of the arguments over the last 2 years would have ever happened, the forum would have been a much happier place.

[puttputt]

I don't know Wasp, I think everyone except you 2 get alot of enjoyment out of your debates

[chimera]

I don't know Wasp, I think everyone except you 2 get alot of enjoyment out of your debates

i'll give it a week and one or both will be suspended. they're not debates, they're ridiculous arguments over trivial things. you said i said he said she said. clearly neither like to be wrong regardless of any literature or otherwise. give it up or i'll lock this thread!

[lduncan]

Wasp you're still trying to drag this down to being a personal thing. It's not. I've posted why I asked the question. Here it is again:

You know wasp, I was not trying to pass this of fact right from the start. It was a question "are you sure?". Why did I ask the question? Because I had seen this passage:

Quote:

Myth: A Low KH results in a larger pH swing when adding CO2.

Many people are under the mistaken impression that a low KH results in large pH swings when adding CO2, while raising the KH will result in smaller pH swings. This is not the case. The KH will move the start and end pH values, but the pH swing will be the same for a given level of CO2. You can see this in the chart below, or using the calculation:

Case 1: Assume a KH of 15 degrees, and a starting CO2 level of 4.5ppm, which would result in a pH of 8.0. If we then add CO2, to increase the CO2 level to 28ppm, that would drop the pH down to 7.2, for a pH shift of .8.

Case 2: Assume a KH of just 1.5 degrees, and a starting CO2 level of 4.5ppm, which would result in a pH of 7.0. If we then add CO2, to increase the CO2 level to 28ppm, that would drop the pH down to 6.2, for a pH shift of .8, the exact same as in case 1.

One possible explanation for this myth is that many copies of this pH chart skip some of the higher pH values, for example, jumping from pH 7.4 to a pH of 8.0. If the reader didn't pay careful attention, they might mis-interpret the size of the pH swing. I specifically made sure to include all pH values, between 6 and 8, in steps of .2.

This relationship will break down at extremely low KH levels (below 1 degree), when there isn't enough carbonate to completely buffer the acids present. In that case, the pH can drop quickly and dramatically. But if the KH is 1 degree or higher, then the size of the pH swing when injecting CO2 will be determined only by the amount of CO2 dissolved in the water.

And I wanted to find out if in fact it was correct. I asked you if you could explain it, but there was confusion on what I though, and you thought you were saying. So I wrote some equations. Then asked Randy for his input. He said that the concentration of carbonate is not constant, something which I had missed, but from his graphs it looks as though within a 1 meq range the pH change is pretty close, even when carbonate is factored in.

Layton

[chimera]

well that was a fast response, sent email to american marine at 11:46am, got a reply at 11:49am. said it probably needs a probe replacement unless water got into it causing corrosion - covering their butts i guess.

[lduncan]

I would suspect corrosion or salt creep if turning the calibration screw through it's full range doesn't correspond to a sweep of values on the display. If that's the case it may still be fixable.

[chimera]

might open it up tonight first - looks like its just a pententiometer so should be easy enough to see if its that thats the problem or not.

cher

[wasp]

i'll give it a week and one or both will be suspended. they're not debates, they're ridiculous arguments over trivial things. you said i said he said she said. clearly neither like to be wrong regardless of any literature or otherwise. give it up or i'll lock this thread!

I agree with you both, no doubt these stupid arguments do provide some amusement. But to me, I find them degrading.

In fact, I will often not post something, knowing Layton will automatically want a stupid argument over it. Notice I at first tried to avoid this last one, even although I knew I was right, however Layton just HAD to persist.

Sadly, Layton will always keep arguing, even when he is wrong, as he has just demonstrated.

Layton I feel you have over 2 years made us BOTH look like jerks, and I am insulted that you persist with this. Having said all this, you do have many good attributes, if you could stay with what you do know, for example electronics, you can be an attribute to the forum.

[lduncan]

wasp, are you able to explain why this is wrong?

Myth: A Low KH results in a larger pH swing when adding CO2.

Many people are under the mistaken impression that a low KH results in large pH swings when adding CO2, while raising the KH will result in smaller pH swings. This is not the case. The KH will move the start and end pH values, but the pH swing will be the same for a given level of CO2. You can see this in the chart below, or using the calculation:

Case 1: Assume a KH of 15 degrees, and a starting CO2 level of 4.5ppm, which would result in a pH of 8.0. If we then add CO2, to increase the CO2 level to 28ppm, that would drop the pH down to 7.2, for a pH shift of .8.

Case 2: Assume a KH of just 1.5 degrees, and a starting CO2 level of 4.5ppm, which would result in a pH of 7.0. If we then add CO2, to increase the CO2 level to 28ppm, that would drop the pH down to 6.2, for a pH shift of .8, the exact same as in case 1.

One possible explanation for this myth is that many copies of this pH chart skip some of the higher pH values, for example, jumping from pH 7.4 to a pH of 8.0. If the reader didn't pay careful attention, they might mis-interpret the size of the pH swing. I specifically made sure to include all pH values, between 6 and 8, in steps of .2.

This relationship will break down at extremely low KH levels (below 1 degree), when there isn't enough carbonate to completely buffer the acids present. In that case, the pH can drop quickly and dramatically. But if the KH is 1 degree or higher, then the size of the pH swing when injecting CO2 will be determined only by the amount of CO2 dissolved in the water.

This is what made me ask in the first place. It seemed to contradict what I had heard from elsewhere, and what you had said.

What I wanted to know was the truth. That's all. I wasn't saying you were wrong, i was asking a question. The above explanation "seemed" to correspond with Randy's graphs, and it "appeared" that it was correct. And i'm still trying to fully get to grips with what is actually going on in terms of chemical equilibrium. I get it in "general" terms, just not quantitatively.

I wasn't arguing, I was trying to understand what's actually going on. If you do fully understand what's going on, i'd be interested in the quantitative analysis of it.

The part where these threads go off the rails is where you try and make it personal, claiming you're being victimised.

Layton

[wasp]

This is what made me ask in the first place. It seemed to contradict what I had heard from elsewhere, and what you had said.Layton

Let's face it Layton, a lot of stuff you come up with seems to be contradictory. This is one of the problems with the way you post unidentified, anonymous quotes, and hold them up as gospel. Anybody could have said them. Another problem is the way you like to post "myths", and "facts". A lot of your "myths" are facts, and a lot of your "facts", are myths.

What I wanted to know was the truth. That's all. I wasn't saying you were wrong, Layton

You were saying I was wrong, and as usual, that was your preoccupation, not the truth. To say otherwise is just more word games.

If you were really interested in finding and sharing the truth, when Randy gave it to you, you would have come back to this forum & shared it. Instead, you went strangely quite because to your horror what Randy explained to you was what I'd been saying the whole time.

Of course, if you had been right, you would have been back here with it in a flash. As demonstrated by how fast you came back with that graph you thought proved me wrong :lol: .

Anyhow, the way you insist on arguing even when wrong is really sad. You always just HAVE to win. But that is not life Layton, and as you get more mature perhaps you will learn to look before you leap.

I'd now suggest you take the advice I offered a few pages back, and get over it.

But if you can't, send me a pm, don't degrade the thread even more. If you are still trying to win this, you won't, because you are wrong, plain & simple. Let it go, it's a learning experience for you.