Rising Ph D:

[raptorrex]

I agree that CO2 gas-off is a very common reason for seeing pH rise in the 24 to 48 hour period after water is drawn from the tap.

I may be missing some information but I've never thought the water authority actually added any CO2 to tap water but that a higher concentration of CO2 was simply -able- to be retained in water that is under higher pressure, such as while it is in the urban pipe system where large water tower is holding a massive weight of water volume that bears down on the water in the pipes. As soon as you draw it out of those pipes and allow it to return to atmospheric pressure, it re-balances to the lower amount of CO2 that can be held at the lower pressure.

An off-topic thing of interest to throw in while we're all thinking about CO2 is that CO2 is much, much less abundant in water than it is in air. One of the reasons that vascular land plants had a hard, slow time of it evolving back down in to the water was that CO2 was so much less available. Plants that can put leaves on the water surface or that actually project leaves above the surface have access to vastly greater amounts of CO2 and can use it to advantage. CO2 is by far the preferred molecule of most plants for "making" their daily simple sugars with which to move energy around among their tissues. Hydrogen and Oxygen are used by plants a lot but are readily available from water itself, but Carbon, which is also greatly needed, is often a major limiting factor for plants.

~~waterdrop~~

actually, well in the UK anyway, water authorities do add CO2 to the water. this, as you have said, lowers the PH (avoiding build up in the pipe, of scale). but the rest goes as you have said. however companys are being asked to reduce this. (global warming)

but yes the CO2 is placed there by the companies, deliberately.

 

[waterdrop]

I agree that CO2 gas-off is a very common reason for seeing pH rise in the 24 to 48 hour period after water is drawn from the tap.

I may be missing some information but I've never thought the water authority actually added any CO2 to tap water but that a higher concentration of CO2 was simply -able- to be retained in water that is under higher pressure, such as while it is in the urban pipe system where large water tower is holding a massive weight of water volume that bears down on the water in the pipes. As soon as you draw it out of those pipes and allow it to return to atmospheric pressure, it re-balances to the lower amount of CO2 that can be held at the lower pressure.

An off-topic thing of interest to throw in while we're all thinking about CO2 is that CO2 is much, much less abundant in water than it is in air. One of the reasons that vascular land plants had a hard, slow time of it evolving back down in to the water was that CO2 was so much less available. Plants that can put leaves on the water surface or that actually project leaves above the surface have access to vastly greater amounts of CO2 and can use it to advantage. CO2 is by far the preferred molecule of most plants for "making" their daily simple sugars with which to move energy around among their tissues. Hydrogen and Oxygen are used by plants a lot but are readily available from water itself, but Carbon, which is also greatly needed, is often a major limiting factor for plants.

~~waterdrop~~

actually, well in the UK anyway, water authorities do add CO2 to the water. this, as you have said, lowers the PH (avoiding build up in the pipe, of scale). but the rest goes as you have said. however companys are being asked to reduce this. (global warming)

but yes the CO2 is placed there by the companies, deliberately.

Wow rap, that is totally interesting! How have I missed this? I am now due for another trip down to my water lab (I live in a university town and the local water lab is chock full of kids bent on getting their PhD in things like water chemistry, lol, so sometimes I can get a good "talking to" from them.) ('course I say that and then who knows, they might ignore me.) I wonder if we're doing the same thing here and how common it is overall?

WD
edit: Well, a quick perusal of some of the posted governmental policy statements immediately shows that yes indeed the diffusion of CO2 into the water supply is recommended in cases where water needs "stabilization" (which I'll assume for now means an effort to keep the minerals from leaching out of the water and building up on the pipes.) And, also interstingly, all the policy things I read are clearly focused on human safety (as they should be of course, as a first thing) with guidelines for getting the CO2 vented out to the outdoors if it leaks and having alarm systems and such since the gas is dangerous in large amounts. So this is yet another of the many ways we humans are adding to global warming... Let's see, lol, there are about 22,000 treatment plants in the USA..sheesh!

 

[raptorrex]

I agree that CO2 gas-off is a very common reason for seeing pH rise in the 24 to 48 hour period after water is drawn from the tap.

I may be missing some information but I've never thought the water authority actually added any CO2 to tap water but that a higher concentration of CO2 was simply -able- to be retained in water that is under higher pressure, such as while it is in the urban pipe system where large water tower is holding a massive weight of water volume that bears down on the water in the pipes. As soon as you draw it out of those pipes and allow it to return to atmospheric pressure, it re-balances to the lower amount of CO2 that can be held at the lower pressure.

An off-topic thing of interest to throw in while we're all thinking about CO2 is that CO2 is much, much less abundant in water than it is in air. One of the reasons that vascular land plants had a hard, slow time of it evolving back down in to the water was that CO2 was so much less available. Plants that can put leaves on the water surface or that actually project leaves above the surface have access to vastly greater amounts of CO2 and can use it to advantage. CO2 is by far the preferred molecule of most plants for "making" their daily simple sugars with which to move energy around among their tissues. Hydrogen and Oxygen are used by plants a lot but are readily available from water itself, but Carbon, which is also greatly needed, is often a major limiting factor for plants.

~~waterdrop~~

actually, well in the UK anyway, water authorities do add CO2 to the water. this, as you have said, lowers the PH (avoiding build up in the pipe, of scale). but the rest goes as you have said. however companys are being asked to reduce this. (global warming)

but yes the CO2 is placed there by the companies, deliberately.

Wow rap, that is totally interesting! How have I missed this? I am now due for another trip down to my water lab (I live in a university town and the local water lab is chock full of kids bent on getting their PhD in things like water chemistry, lol, so sometimes I can get a good "talking to" from them.) ('course I say that and then who knows, they might ignore me.) I wonder if we're doing the same thing here and how common it is overall?

WD

CO2 is used in industry, too. to control PH in their waste water systems. the high pressure simply allows the water to contain/retain more CO2 than at 1 bar. as far as i can tell, the rough rule, for water companies, is a reduction of, at least, 1 in the PH of transported water. the aim, i assume, is to get as close to 7 (Neutral), as possible.

 

[waterdrop]

I can't help but have a new image of one of the main causes of black brush algae being some scientist at the water plant who says "get that CO2 level up so we can get the pH closer to neutral!"

(hey rap did you see I added some to my previous?)

 

[ATK!!!]

well im learning a lot of new things now without even meaning too

 

[waterdrop]

the darn thing is that sometimes this forum gets so intersting that my coffee gets cold...

 

[raptorrex]

(hey rap did you see I added some to my previous?)

oops just noticed. yeah, read it now.

unfortunately its all to do with $/£, and stuff the effect. our current economic system may make a, very, few rich. but is destroying our planet and, seriously, harming its inhabitants. human and other. without wanting to get "political". till we decide its not the 1% of the worlds population that make real money, that matter. things will only get worse.

as for countering the CO2 in tap water? give it a vigorous stir, and add a airstone. CO2 doesn't just "gas off"., well not completely. its replaced by O2.

 

[Aqua Tom]

By great odins beard !!!! You mean i was right?

Has to be a first time i suppose.

 

[waterdrop]

Yep, you were right Tom and I'm glad wrote it the way you did - in the end we've both learned a bit thanks to raptor (won't be the first time, as raptor helped me have a whole 'nother round of thinking about media functions a while back)

Forums are just a weird thing, don't you think, like a giant jump-in, jump-out conversation where you keep learning stuff.

this forum is really rough on my fish - another hour where I could have been doing something directly for them, lol

WD

 

[Harlequins]

the darn thing is that sometimes this forum gets so intersting that my coffee gets cold...

I know the feeling well i put the kettle on again 10 mins ago it boiled just waiting for me to tear myself away to make another...

Hey rap - i never realised about the co2 in the water...is that why i get little air bubbles in the tank after a w/c??

 

[waterdrop]

Yes, the little bubbles after water changes are formed because all of the gases, CO2 included, can be in slightly higher concentrations from the pressure of the pipes and since they have now been returned to atmospheric pressure, the water and air seek a new equilibrium. The actual places where the bubbles form are usually at microscopic inflection points such as little bumps, irregularities or dust particles, so in a normal tank this happens all over. If you were to add water that had been sitting out for 48 hours or so I would expect not nearly as many small bubbles to form, although there'd be some if there was mixing force in adding the water I suppose.

WD

 

[raptorrex]

the darn thing is that sometimes this forum gets so intersting that my coffee gets cold...

I know the feeling well i put the kettle on again 10 mins ago it boiled just waiting for me to tear myself away to make another...

Hey rap - i never realised about the co2 in the water...is that why i get little air bubbles in the tank after a w/c??

lol, i have no idea. though your comment makes sense. to be honest, i never get them, now. though, i do, agitate and aerate my water to "gas off" Chlorine (i do use a de-chlorinateor), this helps to remove CO2 as well as Cl.

By great odins beard !!!! You mean i was right?

Has to be a first time i suppose.

lol, often, more than not, if you apply a bit of logic. if something "makes sense", that's how it works. mind you, you need to do the research, to prove, or confirm it!

keep it up!!!!!!!!