Hybrid dosing (4 part?) for pH control during day and night

[Lousybreed]

We all know about the pH swings in a reef tank. Photoperiod starts, pH raises as the coral and algae consume CO2 and produce O2 (I know it’s the zooxanthellae that make the O2) and at night the pH goes down. Inside air carbon dioxide levels affect this too.

Has anyone used the standard bicarbonate/carbonate formula during the photoperiod and then switch over to sodium hydroxide for night period?

My thought is to boost pH at night with the NaOH in an effort to keep the pH of the system relatively constant.

Thoughts? Randy, wanna chime in?

 

[Randy Holmes-Farley]

Some folks have tried to stabilize pH by switching additives depending on time or pH, but I’ve not seen any great reports of a benefit from it relative to other dosing schemes.

 

[Hooz]

Following along to (hopefully) see how this plays out for you @Lousybreed

 

[Randy Holmes-Farley]

Miami Reef tried something similar for a while.

@Miami Reef

This thread also discusses the relationships between pH and alk stability:

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

 

[Miami Reef]

I used to dose Sodium hydroxide during the daylight hours, but now I just dose it hourly because it’s much easier to program it that way.

I maintain high alk (around 10dKH). Higher alk results in higher equilibrium pH. The higher the alk, the more consumption of alk, which means more dosed = greater pH, especially if using hydroxide as the supplement.

I haven’t seen any ill effects of higher alk. Just faster growth and higher pH. A win-win for me. Everything is happy with the high alk.

Ensure your nutrients are always elevated (at least 0.05ppm PO4 IMO and NO3 at least 5ppm) with the high alk approach. No starvation is allowed with that method.

 

[Lousybreed]

If I understand correctly, you can dose the carbonate and hydroxide solutions and this should not cause any precipitation issues. And I will read the articles!

 

[Lousybreed]

I used to dose Sodium hydroxide during the daylight hours, but now I just dose it hourly because it’s much easier to program it that way.

I maintain high alk (around 10dKH). Higher alk results in higher equilibrium pH. The higher the alk, the more consumption of alk, which means more dosed = greater pH, especially if using hydroxide as the supplement.

I haven’t seen any ill effects of higher alk. Just faster growth and higher pH. A win-win for me. Everything is happy with the high alk.

Ensure your nutrients are always elevated (at least 0.05ppm PO4 IMO and NO3 at least 5ppm) with the high alk approach. No starvation is allowed with that method.

So it sounds like it works out nicely!!! Any other pointers let me know!