2 Chamber Ca Reactor??

[Guest snapper]

Other than the obviuos additionally buffereing area/length, why add a second chamber onto a Ca reator?  Is it strictly to ensure all CO2 is consumed/converted before effluent drips back to the tank?

[dgasmd]

As far as I know, yes. That is the only reason.

[Guest JFish]

and by getting that extra CO² out that means more calcium has also been made in the process I believe.

[pez]

There has been some debate on how much co2 is actually removed in the second stage.  In any case, that's the theory - to remove excess (not all) CO2.  In practice, the pH in the second chamber is higher than the first chamber, so dissolution is at a much lower rate.  Having never owned a single chamber unit, I can't comment on how they compare to dual chamber units.

 

-T

[Guest snapper]

What if your single chamber was bigger, say about 30" vive 20-24?

[geofloors]

The first chamber still is a recirculating loop and you need to inject enough CO2 to bring the pH down where it will dissolve the media. It doesn't matter how large it is, you still need to reduce the pH to dissolve the media. Through the output needle valve you control how much effluent leaves the reactor. In a 2nd chamber the CO2 which leaves the 1st chamber will theoretically reduce the pH of the 2nd chanber a little bit and dissolve more media. I have never used a single chamber reactor either so I can't comment on differences. I fill the 2nd chamber every other time I fill the 1st so I feel it is doing something. My reactor effluent flows into my refugium where any excess CO2 will be used up by the macro algae before it returns to the main tanks.

 

 

George

[Guest snapper]

Thanks for all the input.  I've done a lot of reading, but on the tuning/theory side of things I'm still not clear.

 

As far as the "theory of operation,"

 

1.  Will faster/higher volume of recirc equate to longer/better contact time?

 

2.  CO2 introduction rate is the sole factor that controls pH, true?

 

3.  Top down/reverse flow is better?

 

4.  A precision flowmeter can replace a needle valve and bubble counter for CO2 input?

 

5.  I set my effluent rate to match my tank needs, i.e. pH, Ca consumption, Alk depletion, true?

 

6.  What pH, Alk, Ca levels should I have in my effluent?

 

 

Thanks again for the help!

 

Snapper

[pez]

1.  Will faster/higher volume of recirc equate to longer/better contact time?

 

In theory, yes.  However, generally the rate drawn from the chamber is so small that the recirculation (contact time) has little to do with the overall performance.  I'm assuming you want to know if you have a bigger pump if you will be able to use less CO2 or something like that?

 

2.  CO2 introduction rate is the sole factor that controls pH, true?

 

Well, sort of.  The alkalinity and pH of the source water also affects the pH of the chamber.  Well, let me be clear here, the source water affects how much CO2 you need to drop the chamber pH to a suitable level.  The higher the alkalinity of the source water, the more CO2 you need to drop the pH in the chamber.

 

3.  Top down/reverse flow is better?

 

For a single chamber unit, the direction does matter.  You want to pull your effluent from the opposite end that the source water is coming from.  For a dual chamber unit, the first chamber is completely recirculating, so it doesn't really matter where the effluent is drawn from.

 

4.  A precision flowmeter can replace a needle valve and bubble counter for CO2 input?

 

Hmmm, I think you still need the bubble counter.  The flow meter replaces the needle value on the CO2 regulator.

 

5.  I set my effluent rate to match my tank needs, i.e. pH, Ca consumption, Alk depletion, true?

 

You match the input rate of alk/ca to the export rate of alk/ca.  It takes about 2-3 weeks to get things truly stable.  During that time, you burn a lot of test kits.

 

6.  What pH, Alk, Ca levels should I have in my effluent?

 

The pH output depends on a 1 or 2 chamber unit.  Generally the pH of the first stage should be around 6.8 or so.  The second stage us usually around 7.3, but it can vary wildly.

 

The Ca and Alk levels of the effluent are very high, so it doesn't do you any good to measure them.  That's why you have to consistently measure your tank's alkalinity and Ca during the first month of operation.

 

Hope this helps.

 

-Tom

[Guest snapper]

In theory, yes.  However, generally the rate drawn from the chamber is so small that the recirculation (contact time) has little to do with the overall performance.  I'm assuming you want to know if you have a bigger pump if you will be able to use less CO2 or something like that?

 

Tom,

  I'm not too worried about CO2 use over time.  I'm thinking along the lines of if there is more "mix time" then more co2 is used for dissolution, and less enters the sump and contributes to nuisance algae.  Is that accurate?

 

So when you say chamber pH should be around 6.8, how do you measure it?  Is this also the effluent pH?  If so, how do you obtain a stable tank pH of 8.2-8.4?

 

Thanks,

Eric

[geofloors]

There will be plenty of mix time because you run very little water through a calcium reactor per day. I think I run about 1 cup per hour, when you use a 200-300 GPH pump for recirculating there is plenty of contact time in the first chamber. I run 160 bubbles per minutes and 120 Ml per minute of effluent. The more CO2 coming from the reactor into your tank can lower the pH of the tank and aid in excess algae growth.

 

I don't measure the pH from the reactor but the alkalinity of the effluent is so high that it counteracts the lower pH of the effluent once it hits the tank water. If your effluent pH is too low then you will probably see a lower tank pH because the media is less soluable if the pH in the reactor too low.

 

 

George

[Coral Hind]

Geo- Was wondering if you could clear something up for me.  I am still trying to dial my reactor in and I just got really confused.

 

very little water through a calcium reactor per day. I think I run about 1 cup per hour

 

I run 160 bubbles per minutes and 120 Ml per minute of effluent.

 

I must be missing something.  If only 1 cup per hour of water goes in how does almost 1/2 a cup per minute come out?  That is like 30 cups an hour not one.

 

Teach me oh wise one. :D

[geofloors]

You're right, it is close to 30 cups per hour. I didn't do the math this morning but my post was supposed to say 10 cups per hr.

 

 

George

[pez]

Scott,

 

The pH of the effluent will be the pH of the chamber.  You're shooting for 6.8 - 7.3, depending on the number of chambers.  

 

The Ca reactor will give you a solid alkalinity value, so your pH will not be as likely to swing up or down (assuming the alkalinity value is "normal").  If too much effluent enters the system, your tank pH will be very low and you will get a lot of algae growth.  If you start having pH problems (low pH), kalkwasser is your best bet to bump it up.  Off gassing only takes you so far before you have to artificially raise the pH.

 

-T