Which works better for raising pH?

[d2mini]

My calcium reactor is dropping my ph to 7.6.
Would it be more effective to run a second chamber on the reactor or run a c02 scrubber? Other than the media, i have everything needed for the c02 scrubber. I would have to purchase everything for the second chamber for my CaRx. But my main concern is which is more effective at getting the pH back up.

 

[disc1]

Since it is the calcium reactor that is putting the bulk of the CO2 in, I would think the second chamber would be the best bet. Scrubbing CO2 from the outside air might not do as much if most of the CO2 is coming from the reactor.

 

[Randy Holmes-Farley]

If that doesn't work, limewater (kalkwasser) may be the next thing to try.

 

[d2mini]

Since it is the calcium reactor that is putting the bulk of the CO2 in, I would think the second chamber would be the best bet. Scrubbing CO2 from the outside air might not do as much if most of the CO2 is coming from the reactor.

Hmmm"¦ good point.
Although my ph wasn't high before the reactor either. Usually around 7.8-8.1 throughout the day.

If that doesn't work, limewater (kalkwasser) may be the next thing to try.

I'm trying to stay away from a secondary source of dosing if possible, just to keep things simpler when it comes to my alk/calc.
Used to run kalk in the ato until my tank's demand outgrew it, and I was tired of mixing up 45g every couple weeks and dealing with seized pumps all the time.

My CaRx is a life reef and jeff says all over his website that a second chamber won't do anything for additional alk or ph, but he'll make it if you want it. Seems kind of odd to me, but who knows.

 

[Randy Holmes-Farley]

Do you know the pH of the effluent now?

Adding the second chamber will only be useful for tank pH (IMO) if you dial back the CO2 addition rate because you can use less CO2 (that is, use it more efficiently). Otherwise, you are still adding the same amount of CO2 to the tank, and hence having approximately the same overall pH reducing effect.

Blowing the CO2 off off the effluent before it gets into the tank may be preferable.

 

[d2mini]

Yes, the tank pH is what I need to raise. Effluent pH is around 6.4.

 

[Randy Holmes-Farley]

I meant that the second chamber will only be useful if you dial back the CO2. A second chamber will raise the effluent pH, but that doesn't necessarily rise the tank pH.

 

[d2mini]

Thanks, Randy.

I think I see what you are saying. If I have a second chamber, this makes the whole reactor more efficient, meaning i can use less co2, meaning the effluent won't have as much of a lowering effect on my tank ph, correct?

I was under the impression that just having the effluent pass through the second chamber causes the effluent ph to rise. Is this not true?

 

[bertoni]

Passing the effluent over more calcium carbonate likely will help raise the pH of the effluent, but perhaps not enough to affect the tank pH in any measurable way.

 

[Randy Holmes-Farley]

The second chamber does boost the effluent pH, but it still adds the same net amount of CO2 to the tank. So the net balanced reaction is unchanged:

XCO2 + YCaCO3 ---> [added alk, calcuim and CO2] ---> YCaCO3 (in corals) + XCO2

when you add a second chamber, you get:

XCO2 + YCaCO3 + ZCaCO3 ---> [added alk, calcuim and CO2] ---> YCaCO3 + Z CaCO3 (in corals) + XCO2

So the net addition of pH reducing CO2 is the same.


BUT,

if you reduce the amount of CO2 (X- something) to attain the same calcium and alk in the tank (Y), then the net amount of CO2 is less (X-something). That can help the pH from being as low.

 

[bertoni]

:lol: I guess I never thought the situation through. It is the amount of carbon dioxide that matters, of course.

 

[Steveb]

Blowing the CO2 off off the effluent before it gets into the tank may be preferable.

What are the recommended best practices for doing this?

 

[Randy Holmes-Farley]

I've never done it, so I'll leave it to others, but somehow taking the effluent and exposing it to room air before it hits the tank (and hoping that does not go too far, causing precipitation before it hits the tank water). I've heard of folks using some sort of drip plate, but I don't recall the exact setup.

 

[jda]

You can put the effluent into a skimmer. I have heard that helps, but I have never needed to do it since my reactor has never affected my tank PH.

If you are using too much CO2 in the reactor, then the second chamber will not help.

If your reactor is really the root cause of a PH drop, then you are using too much CO2 in the reactor and excess is making it into the tank. A ratio around 40 drips and 6 bubbles per minute will melt most natural material at about 7.65 to 7.70, or so - if you have man made material then you might need to hit about 7.5. A reactor like a Korallin that traps excess CO2 at the top, but using an extended tube down from the top to pickup the water for recirc, can make this very evident if you are not tuned right. If you are positive that you are not using too much CO2, then check your test kit or probe calibration. If these are right, then look to the house air CO2.

 

[d2mini]

A ratio around 40 drips and 6 bubbles per minute will melt most natural material at about 7.65 to 7.70, or so - if you have man made material then you might need to hit about 7.5.

AHAHAHAHAHA!
You sir need to check out my other thread about my reactor troubles.
http://www.reefcentral.com/forums/showthread.php?t=2380167

Seriously though... wouldn't mind more input.
But I'm about to give up on the thing. At my wits end.

 

[Randy Holmes-Farley]

FWIW, all CaCO3/CO2 reactors dump CO2 into the tank and they frequently cause the tank pH to be lower than if not using it. There is no way around it, unless you remove some of the CO2 outside of the reactor.

That said, it can be true that you may be using more CO2 inside the reactor (and hences dumped to the tank) than is actually necessary, and tweakign that may be useful.

This has more on how to diagnose the source of the CO2 (home air/CO2 reactor) using an aeration test:


Low pH: Causes and Cures
http://reefkeeping.com/issues/2004-09/rhf/index.htm