fresh air from outdoors to raise pH

[Gary Majchrzak]

Originally posted by tmz
Sounds like a good day Gary. iIstill think your ph numbers are low especially since you are dosing kalk.

I suspect that I need to recalibrate the probe, Tom. I'm willing to bet dollars to donuts it's actually above 7.8

[tmz]

I like donuts but dollars are better. What kind of donuts?

[tmz]

Gary, Just a thought. I once calibrated my ph monitor with 4.0 and 7.0 solution instead of 7.0 and 10.0 and got low readings. Not that you did that but just in case.

[Gary Majchrzak]

thanks for suggesting that Tom

[tmz]

You are welcome.

[oceanparadise1]

I like chocolate donuts

[josh.vince]

jelly

[Kent E]

I like chocolate with chocolate frosting.

[chrisqueenz]

Boston creme filled..

[Gary Majchrzak]

without any other changes the probe is indicating pH 7.7 right now

[jansenwrasse]

Originally posted by SkiFletch
Personally, I agree with Tom that adding O2 directly to the tank is unfortunately not a good solution for driving out CO2.

I didn't see where tom posted this, but if you plan to remove CO2 what are you planning on it taking its place? O2 is the only option for pH increase as far as safe gasses are concerned.

Originally posted by SkiFletch
Ultimately calcium hydroxide scrubbing (kalkwasser) addition is the easiest measure by far of defeating ambient CO2. Using Outside air can work, but as Tom found, you can't just use long airline tubing as the pressure drop will be too much, gotta get a big tube to the tank then reduce it down just before introduction to the skimmer.

I will agree that Ca(OH)2 is a fine choice for using the CO2 in the water CO2 + OH -> HCO3, but with elevated levels of CO2 indoors the pH will fall back to its low levels with in a few hours.

O2 (out door air) Is the easiest way to fix the problem of elevated CO2.

Oxygen is for sure a very dangerous gas as far as fires are concerned but it is of no danger to people or objects as a gas. Treatment with Oxygen Gas in medical facilities can be of extremely high purity ~90% or higher.

Please don't take this as an attack I have tried to put in smilies as I do not mean to sound rude.

[jeffmerrill]

Here is a great article tha might be useful: http://www.reefkeeping.com/issues/2004-09/rhf/

[blanden.adam]

Originally Posted by jansenwrasse

I didn't see where tom posted this, but if you plan to remove CO2 what are you planning on it taking its place? O2 is the only option for pH increase as far as safe gasses are concerned.



I will agree that Ca(OH)2 is a fine choice for using the CO2 in the water CO2 + OH -> HCO3, but with elevated levels of CO2 indoors the pH will fall back to its low levels with in a few hours.

O2 (out door air) Is the easiest way to fix the problem of elevated CO2.

Oxygen is for sure a very dangerous gas as far as fires are concerned but it is of no danger to people or objects as a gas. Treatment with Oxygen Gas in medical facilities can be of extremely high purity ~90% or higher.

Please don't take this as an attack I have tried to put in smilies as I do not mean to sound rude.

This really isnt true. There isn't a fixed amount of dissolved gas in a reef tank. You can absolutely remove CO2 without adding something to take it's place. Oxygen doesn't really participate in the pH equilibrium either. You could pump pure oxygen into the tank and it wouldn't affect pH, at least not directly.

The reason pumping in air from the outside helps pH is that CO2 builds up in room air, so when your skimmer bubbles the air in you don't extract as much CO2. Outside air often has lower CO2, so you extract more. Nothing really to do with oxygen my friend .

The posted article explains it quite well.

[tmz]

Hello Adam,

This is a nine year old thread;time flies.

Some comments follow in an effort to clarify things for those intersted in more detail.


I agree there is no fixed amount of dissolved gas in a reef tank or in various locations in seawater in the oceans either. Also the concentrations in water vary from those in the atmosphere, generally. Dissolved gases in sea water(nitrogen, oxygen,argon,CO2, hydrogen sulfide, methane et alia vary in proportion and overall concentrations calculated based on gas laws ,such as Henry's law. .Variables like: salinity,depth,temperature and atmospheric concentrations affect the amount of total
and individual dissolved gases in the water.

For perspective ,atmospheric levels are; around 78% nitrogen, 21% oxygen, 10% argon and only .04%( 400ppm) CO2. The water equilibrates to a large extent with the surrounding air at the surface .
In a home or fish tank room the CO2 can easily be 800ppm or even more than twice the amount in the atmoshpere.

As more CO2 hydrolizes , coverts to CO3 and 2 H+( CO2+H2O------>CO3 +2H+), it adds more H+ which lowers the pH. So, lessening the amount of CO2 in the air going into the tank continuously, raises the pH. That can be accomplished with outside air for the room , an outside airline to an aeration device like a skimmer and/ or a CO2 scrubbing device. Increasing the water surface area via the skimmer bubbles and/or surface agitation increase the rate of gas exchange between the tank water and the surrounding air.

Using kalk/lime water( calcium hydroxide Ca (OH)2 slowly and continuously will also continuously reduce the CO2 in water tank water as the oxide forms CO3 by binding with CO2.

I also agree that oxygen has nothing to do with pH and won't raise it or effect CO2 levels ,directly; CO2 independently drives it down and CO2's major source is the surrounding air.

[blanden.adam]

Originally Posted by tmz

Hello Adam,

This is a nine year old thread;time flies.

Some comments follow in an effort to clarify things for those intersted in more detail.


I agree there is no fixed amount of dissolved gas in a reef tank or in various locations in seawater in the oceans either. Also the concentrations in water vary from those in the atmosphere, generally. Dissolved gases in sea water(nitrogen, oxygen,argon,CO2, hydrogen sulfide, methane et alia vary in proportion and overall concentrations calculated based on gas laws ,such as Henry's law. .Variables like: salinity,depth,temperature and atmospheric concentrations affect the amount of total
and individual dissolved gases in the water.

For perspective ,atmospheric levels are; around 78% nitrogen, 21% oxygen, 10% argon and only .04%( 400ppm) CO2. The water equilibrates to a large extent with the surrounding air at the surface .
In a home or fish tank room the CO2 can easily be 800ppm or even more than twice the amount in the atmoshpere.

As more CO2 hydrolizes , coverts to CO3 and 2 H+( CO2+H2O------>CO3 +2H+), it adds more H+ which lowers the pH. So, lessening the amount of CO2 in the air going into the tank continuously, raises the pH. That can be accomplished with outside air for the room , an outside airline to an aeration device like a skimmer and/ or a CO2 scrubbing device. Increasing the water surface area via the skimmer bubbles and/or surface agitation increase the rate of gas exchange between the tank water and the surrounding air.

Using kalk/lime water( calcium hydroxide Ca (OH)2 slowly and continuously will also continuously reduce the CO2 in water tank water as the oxide forms CO3 by binding with CO2.

I also agree that oxygen has nothing to do with pH and won't raise it or effect CO2 levels ,directly; CO2 independently drives it down and CO2's major source is the surrounding air.

Hi Tom,

Geeze. I didn't even notice. It popped up top because of the article article post prior to mine, and i didn't even think to check previous dates. Sincerest apologies.

[mr.maroonsalty]

Im making this up; throwing it the wall and seeing if it may stick. H2O and CO2 are our most critical molecules; O2 is a critical byproduct provided of the aurotrophs. Basic respiration, right? CO2+H2O+energy>C6H12O6+6O2. Corals are nice in that the ones we keep are heterotrophs hosting autotrophs, but everything else most of us want are simply consumers. The more consumers we have the more CO2 is put back in the system. C6H12O6 +H2O+catalyst>ATP+CO2.

Big stretch here because, there is so much going on with gas exchange between the tank and atmosphere, but all the other benifits aside would not making autotrophs a much more important part of our sytems than a simply light small fuge becomes a huge benefit to a stable system?

We see pH drop in winter in our closed up houses, but is this a result of houses being shut more tightly or is it an environmental response do to winter. I believe it the later. This thread floats back to the top as I am again redeveloping what i hope will be tank worthy of consideration.

None of this is any help to having a load of guests, or cooking a giant meal with hours of gas burner time.

The past weeks I have been weighing the values of devoting one of my two best lit display areas with alga, perhaps my sectional sand bed with grasses. Not the place to go into this. Tom is as up on the science of the tank as anyone is especially when you consider his ability to see the whole picture. This is just my two cents I thought interesting to share as it comes up as I weigh things for the future of my tank.

[tmz]

Oxygen and CO2 are necessary but so are many other things, nitrogen alkalinity ,calcium and a myriad of other major minor and trace elements. I wouldn't O2 and CO2 most critical but they are critical.

We see pH drop in winter in our closed up houses, but is this a result of houses being shut more tightly or is it an environmental response do to winter.

Why? How would the animals in the tank react to the season in a closed environment like a reef tank . For some the seasons would be different in their natural environments on given calendar day.
High relative humidity in a closed up house might play role via salt water mist which could rain in some CO2 in addition to high air levels adding to it via gas exchange, though.

[mr.maroonsalty]

There is somewhere around a 25% swing in atmospheric CO2 levels in our northern climate as plants stop and start processing CO2 into sugars and O2.Yes, closed homes do build CO2 from cellular respirafion of its animal occupants, a gas range is about the only other major appliance that should change the balance of gasses as the other appliances are well vented. But there is also just not nearly the same level of O2 to dillute it as well. Back in 08 we were much more hung up on chasing pH than we were not too long after.
It seems tbat when you weigh in the advantage of the added biodiversity that maintaining well a variety of autotrophs to balancing such problems as wintertime CO2 levels, that a more balanced captive ecosystem could be reached that might in fact start asking for additional CO2 along with nitrogen.

[mr.maroonsalty]

I think that i see the workings going on a wee bit clearer this morning and i am not sure our autotrophs would do much in changing the effect the tanks atmospheric CO2 has; the tank just too readily absorbs it.

[blanden.adam]

As a note, plants and algae respire as well. When in the dark, they will contribute to the CO2 released just like a heterotroph would.

[mr.maroonsalty]

Yes they have to grow, but it is not one to one.

[tmz]

Yes they do respire unused CO2 at night ; pH in many tanks drops at night., commonly called diurnal swing. They also produce exudates ,some of which contribute CO2 as bacteria degrade them.

balanced captive ecosystem could be reached that might in fact start asking for additional CO2 along with nitrogen.


There are tanks with high pH ,8.5 plus. Enhanced gas exchange ; CO2 additions are common approaches to bring them down.

This thread of mine on pH may be of interest:

http://www.reefcentral.com/forums/sh...ight=ph+how+to

There are good reasons to manage pH but not at the expense of swinging alkalinity around .

Some examples :

skeletal mass starts to dissolve at pH below 7.7 ;

corals take up HCO3, bicarbonate ,and need to convert it to CO3 , carbonate , to use it to form Ca CO3, calcium carbonate for skeletal mass

-- to do so, they shed H+ in the ECF, which is easier to do when concentrations of H + in the water are lower,i.e the pH is higher. This article by Randy Farley has more :

http://www.advancedaquarist.com/2002/4/chemistry:

this is from it:


In the case of corals, calcification takes place external to the organism. If one thinks of corals as tissue coating a calcium carbonate skeleton, then calcification takes place underneath the lowest layer of tissue (the calicoblastic epithelium, also called the basel epithelium) in a very thin water space called the extracytoplasmic calcifying fluid2



http://www.reefcentral.com/forums/sh...ight=ph+how+to

The recommended range for reef tanks is 7.8 to 8.5 with nsw around 8.2 on average. Fwi I prefer 8.2 ti 8.4 for my tanks.