Evaporation and PH

5BY5LEC

5BY5LEC

Well-Known Member
Hey guys, a quick question. In regards to DWC/RDWC
So if you start with a certain amount of PH 7 water and use some acid to drop it to 5.8, would evaporation over several days cause a slight PH drift down?
The evaporating would effectively concentrate the acid since there is a less amount of water, no?
Pretend there are no plants or other factors causing a PH decrease.
 
3rd Monkey

3rd Monkey

Well-Known Member
No, it should not.

I apologize if this is redundant to what you know.

PH stands for potential hydrogen. Hydrogen and hydroxide are what determines ph. When you introduce ph down, usually in the form of phosphoric acid, it increases the free hydrogen count. Oxygen from the air will bond with the free hydrogen and then evaporate just the same... often increasing ph as it forms hydroxide.
 
Logan Burke

Logan Burke

Well-Known Member
I'm not sure about the affect it would have on the PH down, but evaporation does generally increase the salt concentration in the water causing the ppm's to increase, and the ph to decrease since most nutrient salts are on the low end of the PH scale.
 
5BY5LEC

5BY5LEC

Well-Known Member
3rd Monkey said:
No, it should not.

I apologize if this is redundant to what you know.

PH stands for potential hydrogen. Hydrogen and hydroxide are what determines ph. When you introduce ph down, usually in the form of phosphoric acid, it increases the free hydrogen count. Oxygen from the air will bond with the free hydrogen and then evaporate just the same... often increasing ph as it forms hydroxide.
Click to expand...
Thanks!
 
AquaTerra

AquaTerra

Well-Known Member
If the water is actually evaporating and not just the plant using it then yes the PH would change as so would the salt to water ratio. More ppm from salts vs water would bring the PH of the mix down.
 
5BY5LEC

5BY5LEC

Well-Known Member
AquaTerra said:
If the water is actually evaporating and not just the plant using it then yes the PH would change as so would the salt to water ratio. More ppm from salts vs water would bring the PH of the mix down.
Click to expand...
Thanks! Yeah I figured as much about the PPMs but did not know if that applied to PH.
Now, if it evaporated that much to cause a PH drop the EC would have went up as well? Mine did not, thus ruling that theory out.
 
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