Let's talk about pH stability...

Daniel@R2R · Jul 21, 2023

What qualifies as "stable pH"? How much should/can pH fluctuate without it being a problem? Have you encountered any challenges with pH fluctuations, and how did you resolve them?

How would you explain the importance of balancing pH to someone who doesn't have a deep understanding of reef chemistry (maybe a new hobbyist or just someone who doesn't have a deep level knowledge of chemistry)? How would you explain the role of pH in a reef tank and how to handle it?

exnisstech · Jul 21, 2023

I'm following because I never test pH. I figure it's something I really can't control so I just roll with whatever it is.
I did test pH once a few months ago using a Hanna Checker because I kept reading about people using kalk to raise pH. I have 3 tanks running. One I drip kalk 24/7 50 minutes on 5 minutes off to help reduce the amount of 2 part needed since it's a larger system the other two just get 2 part with no kalk . The tank dripping kalk had a pH of 8.3 the other two tanks were 8.2 and 8.3 so I don't see this pH benefit from kalk I keep reading about

not that I need a pH bump I was just curious so I tested.

Reefer Matt · Jul 21, 2023

My understanding as a general hobbyist is that ph affects carbonate uptake in stony corals. Lower ph inhibits coral growth because the water is more acidic. This is usually from CO2 in the water. I live next to a great lake, and the ph of my tanks is way lower in the summer than the winter, which seems backward to me. I try to keep ph higher than 7.8 in the summer, it goes up to 8.4 in the winter. Daily swings of .2 usually occur with the light cycle. I don't chase ph, but rather try to keep it in a range above 7.8. I don't really notice any ill effects of the lower ph of 7.8.

Troylee · Jul 21, 2023

It works either way.. you’ll get faster growth with a higher and steadier ph.. you can offset your night time drop by using kalk or a fuge on opposite schedule than the lights. I personally have a frag set up in my sump to help offset the night time drop which helps tremendously at the moment.I use to run 8.3-8.4 but the hot summer days keep my house locked up lol.. the dip was when I re wired my Apex up.

StatelineReefer · Jul 21, 2023

Not this.

Doctorgori · Jul 21, 2023

I think that Idiom “ stability, stability, stability “ is VERY important but perhaps overused or maybe misapplied… just IME maybe not a so much a big deal with temperature or pH … what the fluctuation tolerances are, I can’t exactly say but this is a good thread and maybe a timely discussion

Randy Holmes-Farley · Jul 21, 2023

This related thread may be of interest:

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

ReefGeezer · Jul 21, 2023

Back in the mid 90's, I ran a ph Controller that controlled a CO2 Solenoid and a Kalkwasser Solenoid. I set its band for 8.1 to 8.3 and let it maintain the pH. PH remained stable, but back then I didn't know enough to think about alkalinity stability. I wish I knew more about how that system affected alk. I abandoned the idea when the new fangled calcium reactors came out.

Thinking about that set-up, I wonder if it is possible to stabilize pH without varying alkalinity.

Troylee · Jul 21, 2023

ReefGeezer said:
Back in the mid 90's, I ran a ph Controller that controlled a CO2 Solenoid and a Kalkwasser Solenoid. I set its band for 8.1 to 8.3 and let it maintain the pH. PH remained stable, but back then I didn't know enough to think about alkalinity stability. I wish I knew more about how that system affected alk. I abandoned the idea when the new fangled calcium reactors came out.

Thinking about that set-up, I wonder if it is possible to stabilize pH without varying alkalinity.

With a scrubber on a solenoid yes.. my buddy does it.

14 foot reef · Jul 21, 2023

Converted to a dual Mazzi venturi skimmer PH never been higher or more stable

bakbay · Jul 21, 2023

My pH has a wild swing of 0.33 / day! I run a CaRx so pH is depressed so I supplemented with a recirculating CO2 scrubber. The pH in the ocean swings between day & night and winter & summer too, right? Granted that I’m not trying to simulate the ocean params but I don’t actually see any issues with pH swings. Perhaps it’s just that growth is slowed down when I’m out of CO2 scrubber media. I can observe the growth pattern of the Green Slimer and ORA VoodDoo — fastest growers in the tank!

For my tank, I shoot for stable Alk. pH can be “unstable” but as long as it stays above 8, I’m happy.

ReefGeezer · Jul 21, 2023

Troylee said:
With a scrubber on a solenoid yes.. my buddy does it.

What air does he scrub... the whole room or just skimmer input? I wonder if controlling scrubbed air that is being injected into a skimmer would be efficient enough to saturate the water so that CO2 equilibrium adsorption doesn't occur at the system's surfaces from room air that is higher in CO2 than the scrubbed air.

Troylee · Jul 21, 2023

ReefGeezer said:
What air does he scrub... the whole room or just skimmer input? I wonder if controlling scrubbed air that is being injected into a skimmer would be efficient enough to saturate the water so that CO2 equilibrium adsorption doesn't occur at the system's surfaces from room air that is higher in CO2 than the scrubbed air.

Just his skimmer intake.. his ph gets so high it’s on a solenoid hooked to his apex to shut it down and turn it on… he climbing to 8.7

ReefGeezer · Jul 21, 2023

Troylee said:
Just his skimmer intake.. his ph gets so high it’s on a solenoid hooked to his apex to shut it down and turn it on… he climbing to 8.7

Interesting. I wonder what mechanism keeps CO2 equilibrium with household air from occurring. Maybe the scrubber is effective enough to lower CO2 in the entire space. I'd be interested in knowing how much it costs to operate his scrubber. That has always been the deal breaker for me.

Troylee · Jul 21, 2023

ReefGeezer said:
Interesting. I wonder what mechanism keeps CO2 equilibrium with household air from occurring. Maybe the scrubber is effective enough to lower CO2 in the entire space. I'd be interested in knowing how much it costs to operate his scrubber. That has always been the deal breaker for me.

Cheap to set up.. not sure what he spends on media.. replacing it all the time is why I haven’t done it myself.. I can live with 8-8.2 in the hot months and then it climbs naturally back to 8.3-8.4 when I can open windows..

ReefGeezer · Jul 21, 2023

Troylee said:
Cheap to set up.. not sure what he spends on media.. replacing it all the time is why I haven’t done it myself.. I can live with 8-8.2 in the hot months and then it climbs naturally back to 8.3-8.4 when I can open windows..

I truly don't know the pH level in my tank but I might just fire up the old controller to see. I'll need a new probe though.

Troylee · Jul 21, 2023

ReefGeezer said:
I truly don't know the pH level in my tank but I might just fire up the old controller to see. I'll need a new probe though.

I honestly never cared myself but I ended up trading some stuff for an Apex and trident so now I have test… I’m lazy!

shakacuz · Jul 21, 2023

i used to test ph with my hanna egg checker. but found it to be somewhat inaccurate(i had nothing to test against). I bought a milwaukee MC120 pro which i hope to use and cross check with the egg checker.

i don't bother much with PH anymore because its just a parameter i cannot keep stable due to the environment, and lack of equipment. i'm in a small apartment, with my significant other, and a dog. sometimes we have company over so the air quality does worsen compared to when only we are home, or when the windows are open (during the fall). summer we have the AC going and ceiling fans going. i am going to turn my skimmer back online(i struggle with keeping nutrients up due to my clams and bioload), and have it recirculating with co2 media. hopefully i can have somewhat of a boost(dependent on if i even run low PH..)

bakbay · Jul 21, 2023

Troylee said:
Just his skimmer intake.. his ph gets so high it’s on a solenoid hooked to his apex to shut it down and turn it on… he climbing to 8.7

lol - I wish I have that problem! Mine peaked at 8.4. If I supplement using 2-part and/or kalk, I suspect that I can get to that 8.7 territory. However, I'm wondering if there's a rate of diminishing return; understand that the pH's scale is logarithmic. Additionally, I don't think it's worth the risk to peg pH that will ultimately affect alkalinity and subsequently, nuke the tank!

Curious from your example above, what happens if the Apex went down and the solenoid remained open? That might be a bad day right?

Troylee · Jul 21, 2023

bakbay said:
lol - I wish I have that problem! Mine peaked at 8.4. If I supplement using 2-part and/or kalk, I suspect that I can get to that 8.7 territory. However, I'm wondering if there's a rate of diminishing return; understand that the pH's scale is logarithmic. Additionally, I don't think it's worth the risk to peg pH that will ultimately affect alkalinity and subsequently, nuke the tank!

Curious from your example above, what happens if the Apex went down and the solenoid remained open? That might be a bad day right?

I mean it could be of you were out of town.. I think if you’re at work and come home and catch it, that it wouldn’t really be that bad.. I’m not sure how long it takes to climb that high he just told me it was a issue..