PH peaking at end of light cycle?

[Dlealrious]

Hi Guys

I recently fitted my tank with a PH probe as i am dosing Kalk so for a fail safe. I have noticed though that my PH hits its max in the evening once lights are ramping down. Light start ramp up at 9am, max at 1pm to 5pm then ramp down to 9pm. Im dosing 1000mm of kalk a day equal doser over a 24hr period. I run a calcium reactor which does all the heavy lifting kalk is just an experiment really. Unsure if this is normal as when i used to test with PH Pen PH sat at 8.2 during the day and 8 early mornings but pen reading is only 2 figures so could be 8.28 or 8.01 etc.
Any ideas or is this normal.

 

[bubblemytip]

Yes, completely normal. Photosynthesis during the day will increase pH, while increased respiration at night will cause the pH to go back down as CO2 levels fluctuate.

 

[Dlealrious]

awesome thank you

 

[Dlealrious]

Sorry second question, wouldn't having the higher PH during the day have more benefit to growth or not?

 

[rkpetersen]

Increased coral growth been correlated with higher calcium and alk levels.
Higher pH may make growth easier, but pH mostly rises because of coral growth.
Both photosynthesis and deposition of stony coral skeleton take CO2 out of the water, raising pH.

 

[Dlealrious]

Ah cool makes sense cheers