CO2 and PH drop - tweaking sealed rooms

[Guest]

Have to thank Sandman........

Have to thank Sandman........

He was the first to mention it in another thread and we all started talking about it.

I am currently building an aero system. Am going to pump air from outside the room through the root chambers to create a positive pressure environment. Keep CO2 out and hyper-oxygenate the roots. A tweak off TBug and ItsGrowTime's systems. See what happens.

As the Wikipedia site said the pH drop is much more than what is measured due to the fact the dissolved CO2 in the water that has not converted to carbonic acid..... acts as an acid but does not register on the meters. The issue is much worse..... may negate much of the benefits of the CO2 supplementation. Yes the effects are great but what would they be without the hyper-acidic intracellular environment?

Peace

 

[Guest]

Mid Town........

Mid Town........

Sweet room.... man I wish I had that kind of space to work with. Definitely would be broke with filling that place up with all the fixings. Looks like you have a great vent system set up. Awsome. You could definately grow some jolly green giants in there.

Peace

 

[Neptune]

MY reservoirs are 70 gallons, and locacted on the floor along with a small dual outlet airpump oxygenating each reservoir. my PPM of co2 is 800 with lights on, and I have not yet noticed any significant change in PH.

Nothing unusual so far, I'll boost it to 1200ppm co2 in a few days though.

 

[pico]

"The result obtained by Liedl and his colleagues is both amazing and simple: water plays the crucial role! Absolutely water-free carbonic acid is very stable. Liedl calculated a half-life of 180,000 years for it. "However, carbonic acid decomposes immediately if it comes in contact with water. A single water molecule is enough to speed up the decomposition of a molecule of carbonic acid a billion times."

http://www.wiley-vch.de/vch/journals/2002/press/200005press.html

Carbonic acid decomposes immediately when it comes in contact with water.....Interesting.

 

[Guest]

Pico...... great article......

Pico...... great article......

I am going to quote the final paragraph.
"However, carbonic acid is also vital for us: it is an essential intermediate in the transfer of CO2 between tissue and blood, in particular, between the lungs and blood. The transformation of carbon dioxide into carbonic acid is accelerated by an enzyme, carboanhydrase. In solution, thus also in blood, carbonic acid itself mostly dissociates into a bicarbonate anion (HCO3-) and a proton (H+). This equilibrium is necessary to maintain a constant pH level in blood."

The point we are trying to make is that any substance in chemistry that gives of H+ or hydrogen is an acid the bicarb acts as a base but a weak one that would be over powered by the stronger acid state. Even if the carbonic acid immediately degrades (which apparently it does) it still degrades into an acid. Also, the fact still remains that the dissolved and suspended carbon dioxide itself act as an acid also... essentially doubling the effect and even worse is not detected by pH monitors in the totality of the acidic state in the reservoir. The reservoir is a dire concern but the intracellular acidosis will disrupt the normal flow of cations and anions across membranes.... in other words nutrients across the cell walls. The article was very informative and further confirmed what we are all seeing in the applied effect of the scientific data. Thanks for the post. Good research.

Peace

 

[Neptune]

What should your CO2 levels be at week 2 veg under 600w HPS?

Does it matter if I just jam them up to 1500 PPM imediatly?

 

[Guest]

Neptune..... I jam mine all the time......

Neptune..... I jam mine all the time......

I try to keep mine between 1500 and 2000 all the time. Watch it though man. If everything else is dialed in..... in full and complete accelerated veg. you can get like up to 6-8 in growth per day. I know sounds like bullshit, even had someone on here basically say so but I have seen it happen with my own eyes. Shit grows scarily fast. I only don't use it when I am trying to keep them in a holding pattern. I am not sure what they will do with all organics... you are an organics person if I remember right. Would like to hear back about it.

My up coming thread I will not be vegging long because am going for short SOG but I did my last Blueberry out from seed and vegged for 2 months to age the genetics and see traits before cloning. Would have been over 7ft if not for the snapping of the stems but still ended up 5-6ft. They would recover the next day and would have to snap again. Some were snapped like 10-15 times. The stems stayed hollow and never wooded out. Was a trip. Had to take pics of that. One of these times just for kicks I am going to do a veg with a 6ft yard stick on the wall and do daily shots. Man if you feed them and all else is perfect.......... Like I said scarily fast. I just don't think many have used CO2 in veg. I do because I think it also accelerates the maturation process like about double.

Peace

 

[pico]

"There is a fixed relationship between the pH, KH, and CO2 level. As you increase the amount of CO2 that is dissolved into the water, the pH will drop. And if you then stop adding CO2, the pH will climb as that extra CO2 is released from the water.

CO2 (in PPM) = 3 * KH * 10( 7-pH ) where KH is Carbonate Hardness in degrees

This calculator (and the chart based on this formula) will only work if your water is carbonate buffered. If your water contains high levels of phosphates, it will alter your water properties, and invalidate these CO2 calculations.


http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

1dKh = 17.9ppm CaCO3 dKh = German degrees of hardness (also shown as Kh)

http://www.lamotte.com/pages/common/techtips/convert.html

the warmer a liquid, the less gas it can hold. The cooler a liquid, the more gas it can hold. The same is true for the ocean. If sea water heats up, it tends to release carbon dioxide. If sea water cools down, it tends to soak up carbon dioxide. Carbon dioxide levels in the ocean also depend on other things, like how acidic the water is.

http://www.coexploration.org/bbsr/classroombats/html/co2_in_the_sea.html

The
solubility of CO2 in water depends upon several factors: 1. The pressure of
CO2 in equilibrium with the solution. Solubility increases with increasing
pressure. 2. The temperature. Solubility decreases with increasing
temperature. 3. The pH. The solubility of CO2 increases with increasing pH.
4. The presence of other substances. The solubility tends to decrease with
concentration of "inert" ionic solutes like sodium chloride, but may
increase or decrease with increasing concentration of organic compounds,
depending upon the compound. You can find out "pieces" of the answer if you
do a web search, but I do not know of a single reference that tabulates all
the variables in one place. In general sodium and potassium carbonate or
hydrogen carbonate salts will be more soluble than gaseous CO2 alone.

Vince Calder

http://www.newton.dep.anl.gov/askasci/chem03/chem03416.htm

Some more reading for everyone. The aquarium guys have a lot of info on CO2 injection in water and the pH relationship. The ocean researchers have a lot of good info too.

 

[Guest]

Pico.......

Pico.......

That is some good research there. Good job. Thanks for the info.

Yeah the aquarium guys were definitely farther ahead of us on this subject.

Peace

 

[pico]

Carbon dioxide has a relatively low solubility -- a saturated solution at 25°C is about 0.03 moles/liter -- so not very much of it will dissolve in water.
Of the CO2 that is dissolved, only about 3% will be in the form of carbonic acid. That doesn't mean that the other 97% escapes! It's still in solution. The statement that dissolved CO2 is in the form of carbonic acid is a gross exaggeration

http://www.madsci.org/posts/archives/2006-08/1155473909.En.r.html

 

[Guest]

Again Pico....... great research....

Again Pico....... great research....

One thing for the readers is that "pressure" they are speaking about is the amount of CO2 present in the atmosphere. Inside the body this "pressure" for oxygen in an artery is represented as pAO2 or partial pressure of oxygen.

To point out we do have a lot of phosphates relatively speaking in our solutions.

I have used the phrase dissolved when in actuality I should have used the phrase suspended. The CO2 that is "suspended" in the solution will equalize on the other side of the semi-permeable membrane (in this case the cell wall of the root) and cause intracellular acidosis, which as I have stated before, will alter the exchange of anions and cations (in this case nutrients). The net effect of this alteration is unknown and even to what extent is unknown. It is my worry that we do get an undisputed positive effect with CO2 supplementation but is some of this effect negated by the aforementioned intracellular acidosis. I have searched and searched but have not found a single study that involved CO2 supplementation with prevention of its effect on the solution. The results might be negative, positive, or even astounding. I have designed an aero system with ideas taken from TBugs, ItsGrowTime, and an unnamed source, that will do just that. I will be starting that thread in the next two weeks. I am very anxious to see what the results will be. I may put one plant in a bubbler bucket as a control subject since I don't want to dedicate half of the room to a side by side.

Peace

 

[coolx]

perhaps this should be in a new thread but is at lease tangentially relevant, but the nutes I am going to use (House and Garden - Van de Zwaan) specifically say do NOT use an air pump in the res, and Dave at BGHydro says that this is cos it will cause ph drift all over the place. Anyway, just finished setting up my sealed room - plants go in Thursday.

 

[Guest]

Coolx.......

Coolx.......

I think I will call that company and see if their tech support can give me a reason why. Technically enough oxygen should diffuse into the fluid but wouldn't seem like it would be optimal. I wonder if they have seen problems due to what we have been talking about and not known that was what was causing the issue. Have never heard of it from a nute manufacturer. Let everyone know if I find out anything.

Peace

 

[coolx]

Link is http://www.humboldtwholesale.com/products/HG_Van_de_Zwaan_Cocos_AB.php

I was a little concerned about no oxygen in the nutes - and don't know if this is product specific as they say "Contrary to what you have heard with other products, do NOT use and oxygen pump ....."

 

[Neptune]

MY PH is unaffected by a CO2 ppm of 1200.

No change over a 1 week period. if anything, my PH is drifting up.

Dual outlet air pump into each res.


My water is very hard, 200ppm during winter. This could help to "fend off" the CO2 PH drop... or not. Not a good study becuase I dont use RO.

 

[pico]

the hardness of the water will not change the ammount the pH is dropped.

I plan on doing a test with a few different buckets of water in my room. some with nutes/ some not. some with airstones, some not. some with co2, some not......Get to the bottom of this.

 

[Guest]

Why aren't you guys working in labs or greenhouses? You do know they pay people to do this type of work/research right? lol

 

[mace_ecam]

the hardness of the water will not change the ammount the pH is dropped.

I wouldn't be too sure of that, the calcium in the water is reacting with the CO2 from the air, creating calciumcarbonates, a very strong alkaline buffer.

 

[pico]

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.


http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

Sorry, I should have posted this for reference in my last post. Remember KH refers to carbonate hardness.

 

[Guest]

I actually have worked in and with many labs......

I actually have worked in and with many labs......

I wish I could work in a combo lab and green house to study my favorite subject the Cannabis Sativa. Maybe someday. Use double blind, controlled studies to assess these variables, instead of conjecture or inference.

Opps, slipped into my other personality, again. Seriously, it would be fun as hell. I would definitely donate time to such endeavors. In actuality we really practice on the cutting edge of advanced horticulture.

I often times think I should have gone into research instead of direct practice. They say the devil is in the details and as we often see in our craft, it is.

Oh, by the way..... Excellent posts and research, Pico. Some very enlightening principals but hard to decipher the outcome of their applications. We do need a combo lab and green house.

Peace