How do I raise my Alk levels

[Chris Jury]

Call me crazy, but did anyone actually HELP this poor guy with his tank problem?

I think it's time to (I know, not the popular option) lock this thing down. It's never going to end.

And quite frankly, I'd like to see the poor guy get his tank under control more than I would like to see which one of these guys can piss further into the perverbial wind without getting wet.

We've done this member a great disservice by allowing his question to become a soap box contest for egos.

I for one am embarassed. And you guys should be too.

Chase, you have my apologies that this even ocurred at a time when you were trying to get help with your tank. If I knew how to help you, I would do it myself.

I've tried to do my best at answering the questions originally posted and getting back on track.

Chase, I wrote a response above in the midst of...well, this. I'll copy here so that hopefully it is more visible. If you have any further questions, I'd be happy to answer them.

Quote from: chase33 on September 16, 2007, 10:17:52 PM
Over the last week or so my ALK levels have tested pretty low. I am trying to find out how to raise them. Today it tested at 5.8 DKH (2.06 MEQ/L) and has tested around that value lately. I use the Salifert test kit and have been told by Salifert that there are no problems with the kit tht I have (theyve tested it). Here are my test results taken today at 8 PM (3 hours after lights came on).
Temp = 77.9
CA = 410 PPM
ALK = 5.8 DKH, 2.06 MEQ/L
PO4 = 0.03 PPM
MG = 1250
PH = 8.4
Salinity = 1.024
Nitrate, Nitrite and Ammo = 0

I've started dosing my system last week using the two part system, Anhydrous CAC12 and Arm & Hammer Baking Soda. Reading the Chemistry calculator on Reef Central it states in order to raise my CA an ALK levels to 420 and 2.9 respectively I need to add the following:

2.9 tsp of the calcium solution &
7.9 tsp of the baking soda solution

More information:
120 gallong tank, 40 gallon sump
Approximately 200 #'s of Live Rock
Approximately 250 #'s of Sand

1. If I add the 7.9 tsp of the baking soda solution will this raise my Alk levels?
2. If yes to question 1, can I add all at same time or at what dosage?
3. What amounts of both solutions should I add to maintain adequate levels - I assume I should find out the amount of CA & ALK decreases each day before that determination can be made or am I wrong?

Hope I added all info needed. I'll test again tomorrow.



This is the original post in this thread. So as to maintain some semblance of usefulness, and so as to get toward answering this person's questions I'd like to respond just to this original post.

That all sounds about right. You can add the baking soda all at once. It will lower the pH from 8.4 to ~ 8.3 assuming all your calculations were done correctly. By this I mean that you correctly calculated your water volume and therefore that amount of baking soda will raise the alkalinity by the calculated amount. If it raises the alkalinty more than that the pH will fall more, though even at double the desired change you're still only drop your pH from 8.4 to ~ 8.2, which is fine IMO.

To maintain your calcium and alkalinity I'd closely follow Randy's recipes for making up stock solutions. Ideally you'd be able to accurately weigh out your CaCl2 and NaHCO3. You want to end up with a 1:2 molar calcium:alkalinity ratio since that is the ratio in which they are used. Unfortunately measuring by volume is not very accurate. To really be accurate you need a mass measurment. Please do understand that a 1:2 ratio here is a MOLAR ratio, not a mass ratio. Calcium chloride usually comes as calcium chloride dihydrate (CaCl2*2H2O). The mass of the whole thing in grams is equal to 1 mole. Sodium bicarbonate comes as just that (NaHCO3). The mass of this in grams is equal to 1 mol. You can calculate the mass of 1 mole of either of these (or anything) by adding up the formula weight for all the elements in the compound (e.g., 1 calcium = 40.1, 2chloride = 2x35.5 = 71, 2H2 = 4x1 = 4, 2O = 2x16 = 32).

Once you have balanced stock solutions you just need to keep track of how fast calcium and alkalinity are getting eaten up and dose appropriately. Note: there is more than 4x as much calcium in sea water as alkalinity and calcium gets used at 1/2 the rate of alkalinity. A big change in alkalinity causes a small change in calcium. Even if it seems like alkalinity is dropping while calcium is pretty stable, they are both dropping. This drop is just a lot easier to measure with alkalinity than calcium.

cj

And to clarify, when I talk about the addition of baking soda lowering pH, this will be the effect on pH immediately after the baking soda is added. Given enough time eventually CO2 will be lost from the water (either to the atmosphere or to photosynthesis) and the pH ultimately will be higher than when it started. You will end up with higher alkalinity AND higher TCO2 in your water, but the ratio of alkalinity:TCO2 will be higher than it previously was, thus producing an increase in pH.

cj

 

[Chris Jury]

In response to the questions Boomer brings up:

At any given pH we have a given ratio for total alkalinity:total inorganic carbon. At normal seawater pH (8.20 on the NBS scale) this ratio is about 1.13:1.

If our aquarium is at equilibrium with the air over it, the concentration of CO2 in the water is a function of the partial pressure of CO2 in the air (pCO2). The amount of carbonic acid (H2CO3) is a function of the amount dissolved CO2. At normal seawater salinity = 35, temperature = 25 C and pressure = 1 atm the ratio of dissolved CO2:H2CO3 is about 670:1. The amount of bicarbonate (HCO3-) and carbonate (CO3--) is a function of the alkalinity (technically, we really should consider just the carbonate alkalinity, and not the total alkalinity) and the pH. The lower the pH the less carbonate there is while the higher the pH the more carbonate there is. At normal salinity, temp., pressure in sea water with standard pH and alkalinity the ratio of bicarbonate:carbonate by concentration is about 8:1.

If we put in an additive that provides either alkalinity or inorganic carbon or both in the water then we can take our tank away from equilibrium with the air. It takes time for it to come back, but eventually it will return to equilibrium (though this may take hours to days depending how far we are from equilibrium and the opportunity for diffusion of CO2 in or out of the water).

If we add kalkwasser we add alkalinity but no carbon. This means are ratio of 1.13:1 becomes skewed in favor of alkalinity (for example, 1.5:1). This results in an immediate increase in pH. This also turns a lot of CO2/H2CO3 into HCO3- and CO3--. This means that the concentration of CO2/H2CO3 in the tank is now lower than what is in the air. CO2 will dissolve into the tank and come back to equilibrium with the atmosphere. However, we have increased the alkalinity but the amount of CO2/H2CO3 dissolved in the water depends on what is in the atmosphere. This means that we don't see an inrease in CO2/H2CO3 above what we had previously. Our TCO2 is higher because we have more HCO3- and CO3--, but the CO2/H2CO3 has NOT increased. This means that we not have a slightly higher alk:TCO2 ratio than we did before, and a slightly higher pH.

If we add carbonate the same thing happens as above, except that we ARE adding carbon along with our alkalinity. We are adding alkalinity:carbon at a 2:1 ratio though, so the immediate effect is an increase in the alk:TCO2 ratio (though a smaller change than above) and an increase in pH. Since this ratio is not as far from equilibrium to begin with we come back to equilibrium faster. The overall effect is the same though: increased HCO3-, increased CO3--, the same CO2/H2CO3. Hence, we have a slight increase in the alk:TCO2 ratio, just like above, and an increase in pH.

If we add bicarbonate the reverse process happens. Bicarbonate has an alkalinity:carbon ratio of 1:1, meaning that we will lower our ratio (though not a lot). The immediate effect is to lower the alk:TCO2 ratio, reducing the pH. Much of the bicarbonate stays bicarbonate. Some dissociates HCO3- => H+ + CO3--, producing carbonate and an H+. The H+ combines with bicarbonate so we have H+ + HCO3- => H2CO3. As we've already discussed, there isn't much H2CO3 in water; most of it turns into CO2 very quickly. This means that we increased the concentration of ALL carbon species, including CO2. Now we have more CO2 dissolved in our tank than in the atmosphere. Eventually this CO2 diffuses out into the atmosphere and we end up at equilibrium again. Just like in the above scenarios, the pH ends up higher, the alk:TCO2 ratio ends up higher, HCO3- ends up higher, CO3- ends up higher, and CO2/H2CO3 ends up the same. Since this is the smallest departure from equilibrium, it typically takes the shortest amount of time to come back to equilibrium after this kind of addition.

The last common addition would be calcium reactor effluent. Here we typically have extremly high alkalinty and TCO2 in the water. The alk:TCO2 ratio is in favor of TCO2, however, so we have a low pH--usually something like 6.5. This ratio might be something like 0.8:1. This water is out of eqiulibrium with the tank, being too high in TCO2. Once it mixes into the tank we end up with an alkalinity:TCO2 ratio that is a bit low. This means our pH will be low and that the concentration of CO2/H2CO3 will be elevated relative to the atmosphere. As CO2 is lost to the atmosphere the pH rises an we end up just like above: pH is higher, HCO3- is higher, CO3-- is higher, alk:TCO2 is higher and CO2/H2CO3 is the same. Or at least that is what happens if we come back to equilibrium. Since calcium reactors are constantly dosing, we may never reach equilibrium.

The effect of any of these additive systems on the chemistry of the tank is the same once we return to equilibrium with the atmosphere. Getting back to equilibrium may require many hours or even days. Since we are usually dosing our aquariums more often than that to meet the demands of calcium and alkalinity this means that our tanks may NEVER reach equilibrium with the atmosphere. We may be dosing faster than they can get back to start.

Another thing I'd consider is that often we have elevated CO2 indoors. This means that we can have a lower pH than we want even if the tank DOES come to equilibrium with the atmosphere. In such a scenario adding a high-pH additive like kalkwasser or carbonate can be useful because we then purposefully keep the tank away from equilibrium with atmospheric CO2 and thereby get the pH we want (the one that corresponds to a normal level of CO2).

Chris

 

[Carlo]

Carlo
You didn't read what I wrote. TOTAL VOLUME. Here's an example. If you start with a pound of baking soda and put it in the oven for an hour and end up with 1/2 pound (wild guess) these two (started at same amount) will have the same affect on alkalinity.
I never disagreed with what happens to BS in an oven and how it drives off CO2 or how much x lbs BS = y lbs of SA. My posts were all on what happens when it hits the water and said that is that one needs to worry about if you add the same amounts.
Based on the total volume (unbaked versus baked) the alkalinity affect will be the same (if total volume is dosed) but the direct pH change at dosing time will be different. This is what I was saying in the first place when you tried to correct me. The tank will reach equilibrium in time and the pH will adjust back to "normal".
I missed read this statement as you were adding it to water my fault. Where equal amounts of either will yield the same Alk,. Meaning if 1 tsp of BS is added and 1 tsp of SA is added you will get the same Alk. I can't find the post where I think you said that there is just to much of our crap to read through

That's fine, no problem

If you add equal amount of either by weigh or vol SA, which is how people add it will raise the Alk more than BS. I just showed in my last post that they will not yield the same Alk. I used jd's calculator.

I would 100% agree with that

Here was the post 2 NaHCO3 -> Na2CO3 + H2O + CO2
***More or less baking will only alter the pH rise on addition to the aquarium"***
That must be a typo on Randy's part and not the first. **this part***what is he saying it will only alter the pH when added to the aquarium. That is the error, it will raise the Alk I just showed you in my last post using jd's calculator

I don't even remember where this came from at this point but I believe it was from Randy's article in the same section as the other quote.

Again, I'm pretty sure the ONLY DIFFERENCE of pH changing is in the same regards as above when he was talking about the TOTAL STARTING VOLUME of each before and after baking (not individually by weight or volume). If the ALK is the same the only DIFFERENCE you'll notice upon dosing is pH.

If it wasn't from that section then I'd agree it would be wrong. Depends on the context of where it came from and how it was used.

How about we just let it go regardless?

Carlo

PS IMHO the he said/she said stuff is played out. I'm not going to bring up or quote any posts from the past, unless it has something to do with the original topic. <-- no body need comment, but I know you want to. 8)

 

[Boomer]

Chris

The effect of any of these additive systems on the chemistry of the tank is the same once we return to equilibrium with the atmosphere.......we have more CO2 dissolved in our tank than in the atmosphere. Eventually this CO2 diffuses out into the atmosphere and we end up at equilibrium again.

Thanks for the long post. However, many tanks never get to equilibrium with the air, before other buffer additions are made, not to mention the continuous input of CO2 form marine life, which offsets that equilibrium. In a heavily planted system it is kinda the oppsite, where CO2 levels the water faster than it can enter from the atm. So, although said tank is always trying to equilibrate with the air, in real situations, such as a tank, it often never gets there. So, if two people tried to maintain these levels in their tanks, then tank # 2 would have more CO2 tank #1, even though tank #1 has a lower pH.


#1
pH = 8.1
Alk = 1.5
CO2 = .437 ppm

#2
pH = 8.3
Alk = 4 meq / l
CO2 = .667 ppm pHnnbs




Carlo

http://www.advancedaquarist.com/issues/april2004/chem.htm

This is Randy's article on the above More or less baking will only alter the pH rise on addition to the aquarium

That is a pretty clear cut statement IMHO. He is saying adding your baked BS to the tank will only cause a pH rise and that is incorrect. And bad wording or not that is how people will read that as " If I add some of my baked BS to my tank it will only cause my pH to rise, good, my Alk will stay the same and that is good as it is right where I want it." It will raise the Alk also, so the statement will mislead one.

I would 100% agree with that

OK, you *seemed to me to indicating that was not the case.


In regards to your O2 monitor. Yes, there are some cal solutions one could get to make it work better but I have no ref offhand.

 

[Carlo]

http://www.advancedaquarist.com/issues/april2004/chem.htm

This is Randy's article on the above More or less baking will only alter the pH rise on addition to the aquarium

That is a pretty clear cut statement IMHO. He is saying adding your baked BS to the tank will only cause a pH rise and that is incorrect. And bad wording or not that is how people will read that as " If I add some of my baked BS to my tank it will only cause my pH to rise, good, my Alk will stay the same and that is good as it is right where I want it." It will raise the Alk also, so the statement will mislead one.

I would 100% agree with that

OK, you *seemed to me to indicating that was not the case.

I still think it was in reference the TOTAL AMOUNT but here nor there I agree with you it's very poorly worded at best! No sense discussing what was meant or not by that section since we both agree on how the statement would stand on it's own.

In regards to your O2 monitor. Yes, there are some cal solutions one could get to make it work better but I have no ref offhand.

I sold the Pinpoint O2 Monitor. I'm going back with the Neptune ACIII Pro setup after a carefull and in depth talk with Curt at Neptune to validate it's use. Unless you happen to already know this works fine?

Carlo

 

[Boomer]

You should be fine with that as it has the EC and a link/interfaced to the O2 electronics. I believe that is how that one works, just like other Salinity O2 meters.

 

[Carlo]

Good to know.

Thanks,
Carlo

 

[JDieck]

The effluent is basically carbonic acid and bicarbonate (surprisingly in a properly set reactor very little or no dissolved CO2 contrary to the general belief) In this case, in addition to the bicarbonate partially dissociating into carbonate and H+, we have the combined effect of excess of carbonic acid

I'll preface by saying that this is detail that is probably not useful to the average hobbyist. However, I'm unsure of how Randy is lead to that conclusion. Since the rate of hydration of CO2 over to H2CO3 is very slow (half time of ~ 23 seconds) and the rate of dehydration of H2CO3 over to CO2 is very fast (half time of ~0.03 seconds) most of the carbon between these two species is as CO2. At standard salinity, temp, and pressure there are ~670 molecules of CO2 for every 1 molecule of H2CO3. Since we can't tell them apart by normal analytical means anyway, we usually just write one or the other to represent the sum of both, even though we know that almost all of the carbon here is as CO2. Even so, this is still < 1% of the total inorganic carbon in normal seawater, and not more than ~10 - 15% at the low pH of reactor effluent.

cj

Chris:

Thanks for the explanation, I just want to clarify that it was me with my layman's wording trying to write in English what I was thinking in Spanish the one who wrote that quote not Randy so please hang that ungly one on me and give the inocent absolution. I am convinced that if Randy would have wrote it (And my friend Boom edited it ) it would have been six sigma perfect; (note the statistical joke ;D )
When I wrote it, what I had in mind was CO2g as there seems to be some general concern regarding passing CO2 bubbles out of a reactor if improperly set.
I think I should have quoted something like:
"The effluent is basically CO2a + Carbonic Acid and bicarbonate and surprisingly in a properly set reactor there will be very little or no CO2g (gas) contrary to the general concern. In this case, in addition to the bicarbonate partially dissociating into carbonate and H+, we have the combined effect of excess of COa + carbonic acid"

Also thanks for re-writing the effects of the addition of the different supplementation methods. I was trying to find the graph that shows the percentage (ratios) of the different species versus the PH level and post it here as I think it will help to have a visual aid but could not find one.

JD

PS Hi Boomer, Hi Carlo wana beer?

 

[Carlo]

PS Hi Boomer, Hi Carlo wana beer?

Are you buying? 8)

Thanks much for permission to use that writeup JD.

I guess, that means I'm buying.

Carlo

 

[JohnS_323]

I am convinced that if Randy would have wrote it (And my friend Boom edited it ) it would have been six sigma perfect

Do we have another CSSBB in the house?

Welcome to NJRC JDieck.

 

[JDieck]

PS Hi Boomer, Hi Carlo wana beer?

Are you buying? 8)

Thanks much for permission to use that writeup JD.

I guess, that means I'm buying.

Carlo

Sure you are .... (For every one in this thread) ;D

 

[JDieck]

I am convinced that if Randy would have wrote it (And my friend Boom edited it ) it would have been six sigma perfect

Do we have another CSSBB in the house?

Welcome to NJRC JDieck.

Thanks John, like a shark.... I just could not resist the splashing ;D

 

[Boomer]

You still owe me Beer jd Are you lost again ???

 

[Chris Jury]

Chris

The effect of any of these additive systems on the chemistry of the tank is the same once we return to equilibrium with the atmosphere.......we have more CO2 dissolved in our tank than in the atmosphere. Eventually this CO2 diffuses out into the atmosphere and we end up at equilibrium again.

Thanks for the long post. However, many tanks never get to equilibrium with the air, before other buffer additions are made, not to mention the continuous input of CO2 form marine life, which offsets that equilibrium. In a heavily planted system it is kinda the oppsite, where CO2 levels the water faster than it can enter from the atm. So, although said tank is always trying to equilibrate with the air, in real situations, such as a tank, it often never gets there. So, if two people tried to maintain these levels in their tanks, then tank # 2 would have more CO2 tank #1, even though tank #1 has a lower pH.

Which is why I wrote this:

"The effect of any of these additive systems on the chemistry of the tank is the same once we return to equilibrium with the atmosphere. Getting back to equilibrium may require many hours or even days. Since we are usually dosing our aquariums more often than that to meet the demands of calcium and alkalinity this means that our tanks may NEVER reach equilibrium with the atmosphere. We may be dosing faster than they can get back to start."


JD,

Chris:

Thanks for the explanation, I just want to clarify that it was me with my layman's wording trying to write in English what I was thinking in Spanish the one who wrote that quote not Randy so please hang that ungly one on me and give the inocent absolution. I am convinced that if Randy would have wrote it (And my friend Boom edited it ) it would have been six sigma perfect; (note the statistical joke )
When I wrote it, what I had in mind was CO2g as there seems to be some general concern regarding passing CO2 bubbles out of a reactor if improperly set.
I think I should have quoted something like:
"The effluent is basically CO2a + Carbonic Acid and bicarbonate and surprisingly in a properly set reactor there will be very little or no CO2g (gas) contrary to the general concern. In this case, in addition to the bicarbonate partially dissociating into carbonate and H+, we have the combined effect of excess of COa + carbonic acid"

Also thanks for re-writing the effects of the addition of the different supplementation methods. I was trying to find the graph that shows the percentage (ratios) of the different species versus the PH level and post it here as I think it will help to have a visual aid but could not find one.

JD


Ok, now it makes sense. Yes, there is very little CO2 gas coming out, though there is a lot of dissolved CO2--CO2(aq).

Chris

 

[blange3]

I am convinced that if Randy would have wrote it (And my friend Boom edited it ) it would have been six sigma perfect

Do we have another CSSBB in the house?

Welcome to NJRC JDieck.

Thanks John, like a shark.... I just could not resist the splashing ;D

Sharks, please be gentle with the old men around here that go back to TQM days and can only manage four sigmas. If Demmings or Juran show up in this thread, I'll really be impressed! ;D

 

[Boomer]

Sorry Chris I missed that last part. I stopped at the being of the reactor part.

 

[Chris Jury]

Pssschhh, whatever....

Sooooo not forgiven

cj

 

[JDieck]

You still owe me Beer jd Are you lost again ???

Hi there Boom, No, I'm not lost again..... I'm still lost! ;D

 

[Phyl]

If you guys are lost the rest of us are HOSED.

 

[Chris Jury]

Ha, perhaps

There is a lot that CAN be known about these topics (and a lot that is still unknown to science), but if you understand a few basics you'll be fine.

The most important things to get:

1. Higher alkalinity pushes pH higher.
2. Higher CO2 pushes pH lower.
3. Additivies with balanced alkalinity:CO2 ratios will give the same pH as in a balanced tank.
4. Additives with unbalanced alkalinity:CO2 ratios will change the pH of the tank--this can be good or bad depending on if tank pH is higher or lower than we want.

Most of the rest--all the really complicated stuff--is a more precises refinement of these basic concepts.

cj