Why does PH change after PH is adjusted?

[jaysta]

I always seem to have PH problems with my water/nutes which becomes evident in my leaves/lock out starts to occur.
Why does the PH of water change after it has been PH'd? I.e Yesterday I PH'd my water to 6.5 and left it for 24 hours, today i re-test and my PH'd water has gone back to 7.4? Is that normal or? If that isn't, any idea why this is occurring?

 

[Del boy]

I always seem to have PH problems with my water/nutes which becomes evident in my leaves/lock out starts to occur.
Why does the PH of water change after it has been PH'd? I.e Yesterday I PH'd my water to 6.5 and left it for 24 hours, today i re-test and my PH'd water has gone back to 7.4? Is that normal or? If that isn't, any idea why this is occurring?

i am a novice at this but i find the water temp changes the ph unless my pen is fcked but then i might just be talking bollocks no doubt some one one will give you the correct answer

 

[LeGeneGibberellin]

It has something to do with the alkalinity of the your water.

Water alkalinity and pH: What they mean in regards to water quality

Understanding the difference between alkalinity and pH and how alkaline water can affect plants is important in determining what to do to remedy possible nutritional problems.

www.canr.msu.edu

 

[Proph]

I always seem to have PH problems with my water/nutes which becomes evident in my leaves/lock out starts to occur.
Why does the PH of water change after it has been PH'd? I.e Yesterday I PH'd my water to 6.5 and left it for 24 hours, today i re-test and my PH'd water has gone back to 7.4? Is that normal or? If that isn't, any idea why this is occurring?

Many variables at play.. Are you using tap water? Does your ph up/down have and NPK value or have any nutrients in it? These are the types of questions that first come to mind.

Nutrients take a little time to break down. I would mix the nutrients.. Shake it up well.. Let it sit for an hour.. Then ph it. If the ph is rising like you described, it usually means that there are nutrients still breaking down in the water, which causes on swings. Also things like water temperature and co2 also effect the ph. A swing in is natural. If you are growing in soil, the ph rises as the soil dries.. If you use a res, the ph swings can be due to room/water temp changes.

So yes, ph swings in your nutrient mix is normal. You may just need to check the ph after you mix your nutrients, then let it sit for an hour or two and check/adjust again. That's pretty standard for checking/stabilizing the ph.

 

[jaysta]

Ive only just been testing this with plain tap water (no nutes) as Im trying to work out where I am going wrong. There is no nutes in my PH down. I let it sit for 24 hours, PH, let it sit again for 24 and then re-test and its backup to where it came out of the tap 7+

 

[LeGeneGibberellin]

Ive only just been testing this with plain tap water (no nutes) as Im trying to work out where I am going wrong. There is no nutes in my PH down. I let it sit for 24 hours, PH, let it sit again for 24 and then re-test and its backup to where it came out of the tap 7+

When I fill my reservoir the ph raises drastically for the first few days before getting stable.

 

[Bob's Auto's]

Let me chime in here if you guys don't mind.
The watercompany uses calciumcarbonate to use as a pH buffer. This buffer is added so the pH of their water remains stable under different situations. ie, when you have a waterfilter system in your house you only have to set it for the first week or two. After that the system is running and keeps running how it should without having to be adjusted all the time.

Now Calciumcarbonate reacts with the pH down we put in the water and it tries to stabilize as long as it has buffer to do so. So after adding pH down to your water it is best to aerate it for 24hours after which time you should measure and adjust again. Most of the time adjusting the pH a second time is enough to keep it at the desired pH. Keep in mind that you don't need as much pH down to get it back to the desired pH as the day before.

Regards

 

[jaysta]

Let me chime in here if you guys don't mind.
The watercompany uses calciumcarbonate to use as a pH buffer. This buffer is added so the pH of their water remains stable under different situations. ie, when you have a waterfilter system in your house you only have to set it for the first week or two. After that the system is running and keeps running how it should without having to be adjusted all the time.

Now Calciumcarbonate reacts with the pH down we put in the water and it tries to stabilize as long as it has buffer to do so. So after adding pH down to your water it is best to aerate it for 24hours after which time you should measure and adjust again. Most of the time adjusting the pH a second time is enough to keep it at the desired pH. Keep in mind that you don't need as much pH down to get it back to the desired pH as the day before.

Regards

Thanks for the advice! Would you do the same if adding nutes? Water/add nutes & PH - Wait 24hrs aerating and then PH again?

 

[Bob's Auto's]

Thanks for the advice! Would you do the same if adding nutes? Water/add nutes & PH - Wait 24hrs aerating and then PH again?

Yes I would. You're solution will be much more stable and on the plus side have more disolved oxygen in it.