Odd pH reading in CA reactor

[Wrasse-cal]

@Randy Holmes-Farley,

I have a CA reactor filled with media that I haven't yet started running CO2 through. I was testing the flow and making sure there are no leaks.

Interestingly, my pH probe in my reactor is reading 8.83 while my pH probe in my sump is reading 8.29.

Before I moved one probe into my CA reactor, both probes were in the same sump chamber and reading within .02 of each other.

I'm curious if there is a reason for this variance or if this is more likely evidence that the probe needs to be re-calibrated.

 

[william.sting]

I'd think respiration in your sump and from your main tank could depress pH (co2). Is the ca reactor new and is it currently post of your circulation?

Put the probes back in the same container if your want to be sure they're still calibrated.

 

[Wrasse-cal]

I'd think respiration in your sump and from your main tank could depress pH (co2). Is the ca reactor new and is it currently post of your circulation?

Put the probes back in the same container if your want to be sure they're still calibrated.

The CA reactor is new (hence the reason for leak testing) and it is hooked up and part of my circulation.

 

[william.sting]

That's what I had assumed. What is the flow: main, sump, reactor; or main, reactor sump?

 

[Wrasse-cal]

Reactor is fed off of a manifold from my return pump.

 

[Wrasse-cal]

Reactor is fed off of a manifold from my return pump.

So flow would go:

Display-->sump-->return pump manifold-->display/CA Reactor-->sump-->

 

[william.sting]

Got it.

 

[Randy Holmes-Farley Verified Community Expert]

We’ve seen some folks report elevated pH when starting a reactor, even with CO2. Eventually it drops back.

I’m not sure what exactly is happening. It presumably is some carbonate or hydroxide washing off the media, maybe from a processing/washing step.

What brand media? I assume it was dry when added?

 

[Wrasse-cal]

We’ve seen some folks report elevated pH when starting a reactor, even with CO2. Eventually it drops back.

I’m not sure what exactly is happening. It presumably is some carbonate or hydroxide washing off the media, maybe from a processing/washing step.

What brand media? I assume it was dry when added?

Thanks, Randy.

The media is reborn CA reactor media--the large size. I rinsed it before putting it into the reactor. The pH was at 9.0 a day or so ago, and has been very slowly going down. That would fit with your/others observations it seems.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks, Randy.

The media is reborn CA reactor media--the large size. I rinsed it before putting it into the reactor. The pH was at 9.0 a day or so ago, and has been very slowly going down. That would fit with your/others observations it seems.

I can't find the threads where others saw that, but Reborn might have been the media. In any case, I'd just proceed as usual to add CO2 and lower the pH, maybe keeping closer attention to the pH for a few days.

 

[Wrasse-cal]

Well, I can report today the pH readings are now identical—so it took about a week for whatever to happen to happen.

 

[jda]

They all have dust that you cannot get off with a lot of washing. Output levels are slightly higher for the first day, or two, after a change too... I always assumed that this was the dust getting melted as low-hanging fruit that dissolves easier than the hunks of coral.

IME, small always melts better than large... but also clogs faster.

 

[Randy Holmes-Farley Verified Community Expert]

Well, I'm certainly curious to know why some folks see this.