PH cycles

[jgvergo]

Here is a screenshot of my pH. I have the typical daily swings that are a result of the lights turning on/off. I have also noticed that over a ten day period, there seems to be a larger cycle. If you look at the daily peaks in the graph, you can see that they go from 8.07 to 8.28 and then start to go back down. This larger cycle is constantly repeating. Does anyone have a theory on what might cause this to happen?

P.S. I do have my sump light on an opposite schedule from my DT lights to reduce the pH swings.

 

[lapin]

Guesses:
Changing water or maybe having more people in the house, cleaning glass once a week.

 

[Garf]

Do they coincide with algal growth, either in the display or on a scrubber screen?

 

[jgvergo]

Guesses:
Changing water or maybe having more people in the house, cleaning glass once a week.

The daily cycles are, well, daily. The larger cycle is approximately 2 weeks. I clean my glass every day or two. The longer cycle has no correlation to water changes. The number of people in my house is quite constant.

 

[jgvergo]

Do they coincide with algal growth, either in the display or on a scrubber screen?

I don't see any correlation with algal growth.

 

[BZOFIQ]

My graph looks similar, the last few peaks cover a higher range because it's cooler and our windows are open vs running AC constantly with everything shut.

 

[Garf]

I don't see any correlation with algal growth.

Is your Alk usage / consumption going up and down? Is your pH probe clean, in the dark?

 

[jgvergo]

Is your Alk usage / consumption going up and down? Is your pH probe clean, in the dark?

I don't measure Alk regularly enough to know if consumption is correlated to pH. Probe is clean and in my sump (which gets light every night)

 

[BZOFIQ]

@Randy Holmes-Farley

Randy, we value your input.