PH Conversation

[Skippy The Meh]

I've recently jumped down the rabbit hole of PH and coral growth and best ways to control it.as i understand it: the higher the PH with limit at 8.4 = less hydrogen ions = corals able to build skeletons easier = better coral growth. then opposite for PH below 7.8. anything above 8.4 creates precipitation issues. okay theory makes sense. prior to my current 120 G tank i had a 50 G AIO where my skimmer was small and my ability to increase PH via oxygenation was limited. i did not explore the kalk wasser solution to raising PH. on that tank i made a little DIY CO2 scrubber out of some tubing and air fittings and basically just ran air directly through the the scrubber with no traps, and minimal air dispersion techniques. my PH would sit between 7.9 and 8.0. i had good coral growth so i never messed with it. On my newest tank build i wanted to leverage the sump and big skimmer that sits in it to increase my PH. With no CO2 scrubber the tank was steady 8.0. Well, im into the reefing hobby because its something i like to tinker with and experiment with, im just not the type of person that can sit still and let the tank be. this has bit me in the butt a few time, but hey, it keeps my hands busy. im an Engineer by trade and i like to fix problems, even if they are ones that i create. So last week i decided that PH was something i really, for the most part, have ignored as i just didnt feel it to be a big deal, but wanted to learn about and make optimal in this tank to see if it effected growth rate. So instead of using my DIY co2 scrubber i decided to just purchase BRS's $30 scrubber that is just an RO cartridge. i plumbed it up and let it run for a couple hours before testing. the PH jumped from 8.0 to 8.3.

So now im wondering, is it possible to increase PH with a CO2 scrubber above the 8.4 precipitation threshold? I never anticipated such a quick and drastic jump just with a CO2 scrubber. if so, should i put a Y and gate valve to decrease the efficiency of the CO2 scrubber in the air intake line to the skimmer? What is yalls experiences with PH and if kept in the 8.2-8.4 range, do you really see increased coral growth rates with all other parameters stable? should i keep the CO2 scrubber on there, or is it just the next problem ive created for myself?

 

[NeutronMan]

Mine sits around 8.5 to 8.6 with my c02 scrubber running. 8.1 without.

I dose All for Reef and nothing else that could affect kh.

I took the scrubber offline and watched kh consumption drop. Putting the scrubber back online brought kh consumption back up with one Acro frag showing some substantially increased growth.

I don’t see precipitation anywhere so I’m assuming higher pH might be translating into coral growth. Because of so many variables, I wouldn’t say this is the cause of my observations, but I’m leaving my pH high for the foreseeable future :-)

 

[Randy Holmes-Farley]

I don't know that I agree with the pH 8.4 cut off being important, but higher pH and higher alk can often result in faster hard coral growth.

 

[Beefyreefy]

Any reason you don’t want to use kalk? I don’t think a co2 scrubber alone will raise it that high. I run high ph but via kalkwasser, and the benefit is you can use less (or none) 2part/all for reef. Switching to kalk as my primary calcium/alk/ph driver was the best thing I’ve ever done. Rock solid high PH, fast coral growth, and the coral just seems heartier and less effected by swings or mistakes.

 

[Skippy The Meh]

I don't know that I agree with the pH 8.4 cut off being important, but higher pH and higher alk can often result in faster hard coral growth.

what do you think the number would be to where i should start being concerned about mineral precipitation?

 

[Skippy The Meh]

Any reason you don’t want to use kalk? I don’t think a co2 scrubber alone will raise it that high. I run high ph but via kalkwasser, and the benefit is you can use less (or none) 2part/all for reef. Switching to kalk as my primary calcium/alk/ph driver was the best thing I’ve ever done. Rock solid high PH, fast coral growth, and the coral just seems heartier and less effected by swings or mistakes.

i currently, and have for the past 8 years or so, dosed 2 part. the reason i am not dosing kalk is purely due to unfamiliarity and concerns in spikes as i transition. i recently did some research into it and i really just dont know where to start. would running kalk and CO2 scrubber be too much? what administration method are you using to dose kalk?

 

[Skippy The Meh]

Mine sits around 8.5 to 8.6 with my c02 scrubber running. 8.1 without.

I dose All for Reef and nothing else that could affect kh.

I took the scrubber offline and watched kh consumption drop. Putting the scrubber back online brought kh consumption back up with one Acro frag showing some substantially increased growth.

I don’t see precipitation anywhere so I’m assuming higher pH might be translating into coral growth. Because of so many variables, I wouldn’t say this is the cause of my observations, but I’m leaving my pH high for the foreseeable future :-)

thanks for sharing your tests, that is super helpfull. i wonder at what PH precipitation occurs and if there are other factors that contribute to it. for example higher concentrations of Ca, Mg, K, certain trace elements, or higher Alk levels.

 

[X-37B]

i currently, and have for the past 8 years or so, dosed 2 part. the reason i am not dosing kalk is purely due to unfamiliarity and concerns in spikes as i transition. i recently did some research into it and i really just dont know where to start. would running kalk and CO2 scrubber be too much? what administration method are you using to dose kalk?

I did similar in my 150. Running a carx and a sulfer reactor my ph at night was 7.6 high 8.1.
I cut the carx by 50% and started dosing kalk 24/7. My night-time ph is now 8.0 with an 8.3 high.
I run 2 large skimmers.
I also took the sulfer reactor offline and now dose Vodka to control no3.
I run kalk at 3.5mlm, around 5 liters.
Now I can easily adjust either the carx or the Kamoer with kalk as demand increases.
You can easily do the same with 2 part.
Growth has been noticable.
You can check my build for more info.

 

[Randy Holmes-Farley]

what do you think the number would be to where i should start being concerned about mineral precipitation?

Above pH 8.55, or where you detect it.

 

[Randy Holmes-Farley]

thanks for sharing your tests, that is super helpfull. i wonder at what PH precipitation occurs and if there are other factors that contribute to it. for example higher concentrations of Ca, Mg, K, certain trace elements, or higher Alk levels.

Precipitation can occur at any pH above about 7.7, and it accelerates considerably the higher you go. There is no magic cutoff.

 

[Skippy The Meh]

Precipitation can occur at any pH above about 7.7, and it accelerates considerably the higher you go. There is no magic cutoff.

Ah interesting, thank you! i didnt realize its more of a spectrum and less of an o/off switch per se.

 

[Randy Holmes-Farley]

Ah interesting, thank you! i didnt realize its more of a spectrum and less of an o/off switch per se.

Your welcome!

 

[Beefyreefy]

I use what was and might still be the Chris Meckley. I use saturated kalkwasser top off water, but dose the entire top off daily volume from lights off to lights on. Another alternative is using it as your top off water around the clock. However the lights off dosing keeps ph rock solid comparatively. There are people who run c02 scrubbers on top of this style of dosing, chumminghams reef in particular, and I believe he runs very high Ph like 8.5 or higher. I use a hydros controller to have failsafes to prevent overdosing. I highly recommend dosing with kalk with a peristaltic dosing pump designed for slowly dosing larger volumes of fluids. It can be programmed with a controller and also optical and float sensors get stuck or fail too easily to prevent disasters. You can start with only kalk and no other dosing until alk and PH stabilize and then dose 2part or whatever you like if you need more on top. I dose 2 part on top. Your evap rate changes through out the year so you’ll have to tinker with the kalk dosing volume from time to time, I use the salinity values to keep things in check. I have high rock solid ph all the time now. Only downside is I have calcium build up frequently on return and skimmer pumps because the kalk is dosed into the sump. I clean them more frequently now and it’s no big deal.