Ph cycle and lighting schedule

[Bakki]

Hi everyone,

I was wondering if there are people who adjust their light cycle based on their pH cycle (assuming one has an aquarium controller that continuously reads ph).

For example: if the pH rises until 18h and then flats out, but the lightning schedule is until 21h, could that be an indication the lighting schedule is too long?

 

[Subsea]

I think NO.

Alkalinity is a buffer against pH fluctuations

 

[Dan_P]

Hi everyone,

I was wondering if there are people who adjust their light cycle based on their pH cycle (assuming one has an aquarium controller that continuously reads ph).

For example: if the pH rises until 18h and then flats out, but the lightning schedule is until 21h, could that be an indication the lighting schedule is too long?

Should light schedule reflect the needs of coral rather than pH?

 

[Randy Holmes-Farley Verified Community Expert]

I think he might be suggesting that photosynthesis may be less useful or nonexistent later in the light cycle, and the pH curve might be evidence of this.

One issue is that pH buffering is stronger as pH rises, the effects of more and more photosynthesis will be smaller and smaller as pH in seawater rises (at least to pH around 8.6).

it may also be that organisms are reaching their limit of how much they can or want to photosynthesize, but the question then is whether the light is hurting anything. I don't know the answer, but I would not assume that it is.

 

[Subsea]

I think he might be suggesting that photosynthesis may be less useful or nonexistent later in the light cycle, and the pH curve might be evidence of this.

One issue is that pH buffering is stronger as pH rises, the effects of more and more photosynthesis will be smaller and smaller as pH in seawater rises (at least to pH around 8.6).

it may also be that organisms are reaching their limit of how much they can or want to photosynthesize, but the question then is whether the light is hurting anything. I don't know the answer, but I would not assume that it is.

Dana Riddle has done research on photo saturation of corals.

https://www.reef2reef.com/threads/question-on-photosynthesis-data-from-dana-riddle-articles.543078/

 

[Bakki]

I think he might be suggesting that photosynthesis may be less useful or nonexistent later in the light cycle, and the pH curve might be evidence of this.

Indeed this is what I meant.

One issue is that pH buffering is stronger as pH rises, the effects of more and more photosynthesis will be smaller and smaller as pH in seawater rises (at least to pH around 8.6).

This what I wondered indeed, as a flattening of the pH would not necessarily mean photosynthesis has stopped. A decline while the lights are on are maybe stronger evidence.

@Subsea , thank you for the article. I’ll have a look at it.