PH is highest just before lights turn off

[pickupman66]

So, I think I always knew that when the lights were on, the PH would rise and with them off, the PH would fall. I sort of also pictured it in my mind that as the lights were more intense, then the PH would rise and then fall as the intensity ramped down. However after really tracking this data over the last 5 months (that I have), that is not 100% the case.

My lights come on at 10 am and ramp in intensity over 4.5 hours, have 1 hour of Peak light then ramp down over 4.5 hours to just a faint moon light. that goes completely black at midnight. Moonlight comes on a 1% at 6 am as I kind of like to see it when I am getting ready for work. it is already light at home anyways.
it is neat to overlay these graphs ( pardon the change in the intensity, I had moved the light when we moved so I had to lower it for a period.

Light Ramps

PH Graph

 

[beaslbob]

Looks like you got a little lag. If the lights came on full and turned off full that lag would be not noticeable.

But interesting data anyway.

BTW is this the total lights of the system with no refugium lighting especially with opposite lighting?

 

[pickupman66]

No fuge light.

 

[beaslbob]

probably a lag.

 

[zoomonster]

I'm prone to think lag/error in the reporting software. My light schedule pretty much corresponds to my PH graphs. By the time the lights go off at end of ramp the PH has already slightly fallen from roughly 8.3-8.27 and downwards from there. In the morning/day its a fairly slow climb and reaches peak sometime late day (right now at 8.25). So 3 hr morning ramp, 7 daytime, 3 night ramp with PH low 8.08, avg 8.19, high 8.3. I have a 24x7 lit refugium but it makes trivial difference in PH. Last test maybe .03 difference when I left it off overnight. The real difference is a kalk reactor on ATO keeping calcium reactor in check.

 

[Randy Holmes-Farley]

So, I think I always knew that when the lights were on, the PH would rise and with them off, the PH would fall. I sort of also pictured it in my mind that as the lights were more intense, then the PH would rise and then fall as the intensity ramped down. However after really tracking this data over the last 5 months (that I have), that is not 100% the case.

My lights come on at 10 am and ramp in intensity over 4.5 hours, have 1 hour of Peak light then ramp down over 4.5 hours to just a faint moon light. that goes completely black at midnight. Moonlight comes on a 1% at 6 am as I kind of like to see it when I am getting ready for work. it is already light at home anyways.
it is neat to overlay these graphs ( pardon the change in the intensity, I had moved the light when we moved so I had to lower it for a period.

Does the color of the light change at all through the day?

 

[JimWelsh]

What I see is that there is a consistent, sudden drop of about 0.09 pH units each day exactly when the lights come on, and a similar appx. 0.09 pH unit sudden shift up exactly when the lights go off, suggesting something like a stray voltage or EMF interference issue with the pH probe. If you subtracted that out, and shifted the "lights on" portion of the pH graph up by 0.09 pH units, then the pH graph would look more like what is expected.

There appears to be another thing going on exactly at midnight, and yet another at around 5:00-6:00 AM (assuming the vertical date line demarks midnight).

EDIT: I also see a big jump up right at noon each day, and another thing at around 7:00-8:00 PM. You have consistent, sudden discontinuities happening at the same time every day, but two really big ones happen at "lights on" and "lights off".

I bet if you turned the lights off in the middle of the day, you would find that the pH suddenly goes up by 0.09 units.

 

[pickupman66]

Yes, I know about those. Something to do with the pwm and analog powers within my controller and is something I am chasing along with the manufacturer. The controller also powers on the main circuitry for the light system. The other small increases are 4 daily dosing of alkalinity 2 part. Noon 6, midnight and 6. Color does not change dramatically as the blues and whites ramp the same % thru the day (just whites not as high).

I'm not concerned as overall consistency in my tank is good just something I happened to notice as the tank churns.