Carbonic Acid - Legitimate concern?

[TerpeneTom]

Hello,

I believe I am experiencing dramatic drops in PH due to excessive C02 concentrations being drawn into the H20.

I'm utilizing the PPK method of hydroponic production. What I believe to be relevant is that the you use a pump to simulate flooding within the individual sites, so the H20 acts as a plunger, sucking oxygen (C02 in my case, ~1,000 PPM) into the media, and ultimately the roots. Also, the water is not agitated within the reservoir, so there is optimal conditions for carbonic acid to form.

Is this a legitimate concern when producing cannabis? Why the fuck may this be causing me serious trouble. Is this possible?

I have only conducted experiments via trial and error. I have experienced drops in PH from 6.0 to 5.0 in ~2 hours. So, after I turned it off the PH only dropped from 5.8 to 5.4 in three hours. I have ceased use of C02 overnight, so I will report the findings tomorrow.

Is this even significant?

 

[shaggyballs]

I think plants produce co2 at night might be a overdose??

 

[TerpeneTom]

24/7 schedule.

I input 1.5 ml General Hydroponics PH Up, raising PH from 5.3 to 5.8. Just now I checked my PH and it is 4.9...

I have input around 16 ml total of PH Up over the past 5 days...to no avail.

[FONT=Arial, Helvetica, sans-serif]
I am going to quit pulsing the individual sites now and see if the PH changes drastically within the external reservoir. It seems the issue is when the water is being pulsed, and then the water reaches equilibrium and PH is again very low.
-I turned off the cycle timer and PH'd the external reservoir to 5.8 (from 5.2, with ~1 ml General Hydroponics PH Up), now I will wait and see if the PH drops within the external reservoir in about 2 hours[/FONT].

The water is reacting with something
-I have NO organic matter within the reservoir
-I eliminated the light leak ~3 days ago
-I have input ~15ml H202
-I have input ~16 ml PH Up
-C02 in the room is ~1,000 PPM


During Testing: PH remained stable: 5.8 the entire duration (>1 week)
Inputs that have changed:
-Addition of C02 (From 400 Ambient to 1,000 supplemented)
-Light Leak: 3 days exposed
--35% H202 application, ~15 ml total input throughout the week. Algae should be deceased.
-Changed external reservoir: Sterilite to Rubbermaid
-Plants transplanted: Should have zero effect initially

 

[TerpeneTom]

The PH in the external reservoir has remained STEADY at 6.0 PH after 1 hour 45 minutes. I have not flooded the system. So this seems to rule out the possibility of algae.

So, there is some interaction which is causing this steep decline post flood.

Is something happening within the individual reservoirs? Or is it within the media?

Could the plants, even within the seedling stage alter the PH that much?

 

[BasementBreeder]

Tom,

Are you using RO or tap water? If tap, how hard is it?

 

[TerpeneTom]

R/O. The nutrient is designed for R/O.

Just tested yesterday: 4 PPM

~5.8 PH is the common stable point (every time, very stable nutrient) without any additives or supplements. Something is affecting it.

[FONT=Arial, Helvetica, sans-serif]
[FONT=Arial, Helvetica, sans-serif][FONT=Arial, Helvetica, sans-serif][FONT=Arial, Helvetica, sans-serif][FONT=Arial, Helvetica, sans-serif]Further Test: Added 2 gallons of R/O water to dilute the nutrient concentration. Flooded. Post Flood: 5.3 PH. Now, I will allow the mixture to settle for at an hour before I test PH again. If the solution drops?, then... If not?[/FONT][/FONT][/FONT][/FONT][/FONT]

 

[G.O. Joe]

If the nutes contain ammonium salts, nitrifying bacteria will lower the pH as they convert those to nitrate.

 

[Only Ornamental]

Didn't read the thread yet; sorry.
You said you'd use CO2 during the night, right?
Why that? Most plants, even those using a dark reaction, don't really need it at night which leaves you with an excess which would 'disappear' in the water. Don't know if you have an on-line ppm controlled CO2 delivery but if you do, such a system would constantly pump CO2 into the water, pH drops, the plants run out of nuts and become unhappy...

And now I'm going to read the other posts .

 

[TerpeneTom]

I run a continuous photo period currently.

 

[Granger2]

Why not drop light to 18/6, Cut CO2 off early enough before lights out so levels are at something near 400 ppm at lights out, and see if that fixes the problem? Why 24/0 anyway? Good luck. -granger

 

[TerpeneTom]

This issue has been resolved.

The conclusion: excessive and unnecessary micro management. This hydroponic approach, in addition to a quality nutrient product, self regulates

Thanks.