pH

[Pistondog]

yes it will lower it in a room but removing it from water takes considerably longer even with good surface agitation. My tank dropped to 7.58 last night. I put a fan over the tank drawing fresh air in through a window less than 2 feet from my tank. I also have my skimmer drawing fresh outside air. It took all day for my tank to reach 8.0 From 7.58. I am running a 90 gallon with 2 xf30 at 100% very close to the surface and 1 MP40 @40%.

Thanks for the info.
Is part of that your daily ph rise cycle too?

 

[PbMan26]

Ph dropping at night is due to photosynthesis stopping. That is a normal occurrence since algae or others stop consuming CO2.

 

[Shawn_epicurious]

No, just co2 levels

Carbon Dioxide Detection and Indoor Air Quality Control -- Occupational Health & Safety

Carbon dioxide gas detectors can utilize an automated background calibration program to set the clean air level on a regular basis.

ohsonline.com

Researching...

You Rock!

 

[adobo]

Hey all. To start, want to say I know that chasing pH isn't necessary if my numbers are good. However, I am just curious. If I am pulling air from outside to my skimmer, should pH be 8.3 or higher without other factors? Currently, I bring in air from the outdoors to the skimmer through a scrubber, and dose soda ash. Yet my pH is normally 7.9 to 8.2 (night to day). I have a fuge running at night, and between everything, just seems weird that my pH is so 'low' and I have such low numbers at night. Again, I know it is in range, but 8.3 is what I really want it to be at most times.

I don't know what chasing pH means and I know conventional wisdom is that a pH between 7.8 and 8.3 in reef tanks is sufficient. However, plug in the search for "ocean acidification" and you will see an endless number of scholarly articles on the detrimental impacts lowered pH has on coral reefs.

I always wonder if the current conventional wisdom on pH for reef tanks is because people have actually studied this topic or if it is because everyone was saying it.

 

[themcfreak]

It was @bulkreefsupply that put me onto this @adobo. Ryan said that exact thing about how conventional wisdom says 7.8-8.3 is fine, but ocean is 8.3 and a drop to 8.2 is detrimental to coral in the ocean. There are so many factors, but dropping to 7.9 every night just seems way low when looking at it that way. In one of their newest live from this week, they talked about pegging pH at 8.3 and how it is doable with a CO2 scrubber, yet I can't get up there unless my windows are all open, even though I draw air from outside and go through a scrubber.

 

[themcfreak]

Bioload was mentioned earlier. Which way does that effect pH? More bio load equals higher pH or lower pH?

 

[adobo]

It was @bulkreefsupply that put me onto this @adobo. Ryan said that exact thing about how conventional wisdom says 7.8-8.3 is fine, but ocean is 8.3 and a drop to 8.2 is detrimental to coral in the ocean. There are so many factors, but dropping to 7.9 every night just seems way low when looking at it that way. In one of their newest live from this week, they talked about pegging pH at 8.3 and how it is doable with a CO2 scrubber, yet I can't get up there unless my windows are all open, even though I draw air from outside and go through a scrubber.

I am a layperson so I know about 2 google searches worth of information on this topic (plus what I remember my kid telling me about from her Environmental Science class). I'm wouldn't know the difference in scale of impact a .1 change vs. a .5 change in pH would have to individual organisms. But I did get to thinking, I know in reef tanks that are populated with corals will experience fluctuations in pH. I was wondering if that is also true in coral reefs. I haven't found and answer though I did run across an interesting article that states:

... kelps are responsible for changing pH in the surrounding water, for example, pH in kelp forests exhibits large diurnal fluctuations changing > 0.25 units [23]. Coralline algae themselves can also metabolically modify pH at their surface, within the diffusion boundary layer [20,25]. Therefore, coralline algae, and other associated benthic organisms growing within or near coastal kelp forests are naturally exposed to a daily cycle of both high (~8.86) and low pH (~7.7) [14,23].

I live in Northern California where we have temperate waters and kelp forests so presumably, our coastal waters here have fairly "extreme" swings in pH. I'm still searching the interwebs to see if pH swings are drastic in tropical coral reefs. I did read somewhere that:

Prior to the Industrial Revolution, average ocean pH was about 8.2. Today, average ocean pH is about 8.1. This might not seem like much of a difference, but the relationship between pH and acidity is not direct. Each decrease of one pH unit is a ten-fold increase in acidity. This means that the acidity of the ocean today, on average, is about 25% higher than it was during preindustrial times.

BTW, I don't know how the current conventional wisdom on pH came about but Randy Holmes Farley (someone who seems to know a thing or two about chemistry) wrote an article on low pH. There he states:

The acceptable pH range for reef aquaria is an opinion rather than a clearly defined fact, and will certainly vary based on who is providing the opinion. This range may also be quite different from the "optimal" range. Justifying what is optimal, however, is much more problematic than that which is simply acceptable. As a goal, I'd suggest that the pH of natural seawater, about 8.2, is appropriate, but reef aquaria can clearly operate in a wider range of pH values. In my opinion, the pH range from 7.8 to 8.5 is an acceptable range for reef aquaria, with several caveats.

 

[USMA36]

Bioload was mentioned earlier. Which way does that effect pH? More bio load equals higher pH or lower pH?

My limited understanding is that a heavier bio load lowers the 02 level and could drop pH.

 

[themcfreak]

That makes sense. More fish breathe more O2, put out CO2, lower pH. Thanks

 

[gray808]

I have a Bubble Magus skimmer. How would I set it up to draw outside air?

--Gray

 

[Pistondog]

I have a Bubble Magus skimmer. How would I set it up to draw outside air?

--Gray

There's an air line supplying air to the skimmer, one end at the pump, the other end you need to run out a window, or thru the floor or wall, outside. You will need longer hose and if the run is longer that 10 feet, maybe run wider id tubing for less resistance.
Put a small piece of screen on the outside end to keep bugs out.