Alk oscillations vs pH oscillations

[AlbertGF]

Hi,

I saw a lot of people who dose their Alk solutions at night to rise the pH at night and avoid that day/night pH oscillations. But I suppose that then, Alk will fall during the day and rise at night. So you are helping to avoid pH oscillations but you are creating Alk oscillations, so...

What is better for corals and reef inhabitants??? To try to maintain a constant pH level or to try to maintain a constant Alk level during the whole day???

Regards!!!!!

 

[Randy Holmes-Farley]

Most folks elect alk stability as more important, but this thread pokes at that and what it really means:

Alkalinity stability? pH stability? Are they even different?

It is currently the dogma of the reef aquarium hobby to say that alkalinity stability is very important for SPS corals, and that pH is not. Often, the very idea of someone trying to optimize pH is called “chasing numbers” as if that statement by itself shows it to be foolish. Since I have...

www.reef2reef.com

 

[AlbertGF]

Most folks elect alk stability as more important, but this thread pokes at that and what it really means:

Alkalinity stability? pH stability? Are they even different?

It is currently the dogma of the reef aquarium hobby to say that alkalinity stability is very important for SPS corals, and that pH is not. Often, the very idea of someone trying to optimize pH is called “chasing numbers” as if that statement by itself shows it to be foolish. Since I have...

www.reef2reef.com

Thank you Randy! I'll look at it.

 

[AlbertGF]

Well, after reading the article several times I get the conclusion that bicarbonates vary as pH vary. But I haven't enough knowledge (nor in chemicals nor in english) to extract a clear answer for my question.

My corals get carbonates or bicarbonates or whatever from water during the day (the 24 hours?) so my carbonates level will drop (independently of pH) because corals are extracting them. I think that a constant dosing will be better so carbonates be replenished as corals take it.
My pH oscillate during the day because of the photosynthesis and CO2 concentration (I think) and this makes changes in bicarbonate to carbonate and vice versa. Ok.
Now, is it better to concentrate all dosings over the night to get a more stable pH? Lower at day but higher at night? Taking into account that there will be less carbonates or bicarbonates or whatever during the day because of corals consumption (independently of pH). Or is it better to dose carbonates during all day to replenish them as them get consumed by corals and let the pH oscillate during the day as it normally does?
Or maybe I don't understand anything and I am totally wrong...

Thank you in advance!

 

[Randy Holmes-Farley]

Well, after reading the article several times I get the conclusion that bicarbonates vary as pH vary. But I haven't enough knowledge (nor in chemicals nor in english) to extract a clear answer for my question.

My corals get carbonates or bicarbonates or whatever from water during the day (the 24 hours?) so my carbonates level will drop (independently of pH) because corals are extracting them. I think that a constant dosing will be better so carbonates be replenished as corals take it.
My pH oscillate during the day because of the photosynthesis and CO2 concentration (I think) and this makes changes in bicarbonate to carbonate and vice versa. Ok.
Now, is it better to concentrate all dosings over the night to get a more stable pH? Lower at day but higher at night? Taking into account that there will be less carbonates or bicarbonates or whatever during the day because of corals consumption (independently of pH). Or is it better to dose carbonates during all day to replenish them as them get consumed by corals and let the pH oscillate during the day as it normally does?
Or maybe I don't understand anything and I am totally wrong...

Thank you in advance!

The reason I posted that link is because there is no clear answer about the exact optimal conditions. As I noted above, most folks have focused on alk stability and that is what I would do unless the pH is dropping below ph 7.8 at night.

As tot eh more general question...
Certainly, folks keeping alk very stable claim to see a benefit. Folks with a pH swing do not seem to suffer.

Would stable bicarbonate be better than stable alkalinity?
Would stable bicarbonate with stable alk (meaning stable alk and pH) be better than stable alk alone?

Those are unanswered questions.

 

[rusgum]

Well, after reading the article several times I get the conclusion that bicarbonates vary as pH vary. But I haven't enough knowledge (nor in chemicals nor in english) to extract a clear answer for my question.

My corals get carbonates or bicarbonates or whatever from water during the day (the 24 hours?) so my carbonates level will drop (independently of pH) because corals are extracting them. I think that a constant dosing will be better so carbonates be replenished as corals take it.
My pH oscillate during the day because of the photosynthesis and CO2 concentration (I think) and this makes changes in bicarbonate to carbonate and vice versa. Ok.
Now, is it better to concentrate all dosings over the night to get a more stable pH? Lower at day but higher at night? Taking into account that there will be less carbonates or bicarbonates or whatever during the day because of corals consumption (independently of pH). Or is it better to dose carbonates during all day to replenish them as them get consumed by corals and let the pH oscillate during the day as it normally does?
Or maybe I don't understand anything and I am totally wrong...

Thank you in advance!

If I were you, I would not think about it. I took measurements at the same time and dispensed evenly throughout the day. All the same, you will not catch that period of the day when you need to dose more or less. As practice shows, even capricious corals are fine.