How does it work? Vol 2: Ca reactors

[Moe_K]

Continuing our discussion of how various pieces of our equipment work, and the new trends in technology, lets examine calcium reactors.

First off, can somebody provide us a broad, but basic description of how calcium (Ca) reactors work?

Next, we should discuss changes in the technology.

Then we can discuss models and price, and finally we can get into DIY reactors.

 

[clamm]

well lets see...

you have co2 that is input into a chamber where it is mixed with water it then goes up though a dohickey where pure stuff comes out and drips back into that tank...lowering your ph but increasing your Ca.

I have no clue how it works, im going to tag along and learn.

 

[Mike A]

My take:

CO2 gas is mixed in a closed chamber with system water and a calcium carbonate media. The CO2 gas lowers the PH inside the chamber. The calcium carbonate media starts to slowly dissolve at the lower PH, releasing calcium and carbonate in equal (balanced) ratios. The effluent from the CO2/Calcium carbonate mixture is slowly dripped into your system, adding calcium and carbonate.

 

[nitrofish]

heres my understanding, a tube is filled with a media of sorts and a controled amount of co2 is injected to lower the ph. this lower ph causes the media to breakdown releacing calcium and other trace elements, which is slowly reintroduced into the main tank.

 

[JustDavidP]

If a Ca Reactor works by lowering the PH in the chamber, does the "product" in the end, have a lower PH and does that affect the PH in the display?

 

[stang8s]

If a Ca Reactor works by lowering the PH in the chamber, does the "product" in the end, have a lower PH and does that affect the PH in the display?

Yes and yes. That is one of the benefits of the 2nd chamber in the reactor. There is no co2 being put in that chamber and it is full of arogonite which has a ph raising effect.

 

[Moe_K]

So the make up of the media is important since the media is totally dissolved and the product dripped into the tank. Whatever is in the media will get dripped into the tank, right?

 

[JustDavidP]

Yep...that I do know. I learned about media well before I decided to try a reactor. I'm going to build *nodding*...er...or shall I say.. Gustavo and Dave are gonna build.

I do know that it's much like a database.... Junk in....Junk out. Good media is important. Down to type, size, etc.

 

[Mike A]

Yes and yes. That is one of the benefits of the 2nd chamber in the reactor. There is no co2 being put in that chamber and it is full of arogonite which has a ph raising effect.

It's also the reason why people use solenoid valves coupled with a PH controller. The controller signals the solenoid to open or close depending upon the PH of the system water. If the PH goes below a certain value, the solenoid can be set to close, preventing the flow of CO2 from entering the reactor until the PH rises naturally or open if the PH goes to a higher value (possibly due to heavy use of kalk).

Some folks use timers and solenoids and only administer CO2 into the reactor during daylight hours, as the PH is supressed (lower) during nighttime.

 

[stang8s]

true but its the same as any media you put into your tank. Over time your southdown sand and crushed coral medias on tank bottoms, also break down into the tank. Just takes longer. I have been using crushed coral in my reactor with great results. I have yet to see any scientific data that made me believe that purchasing the fancy reactor medias are worth the $$$

 

[Moe_K]

How much carbon dioxide (CO2) is consumed in a month? These reactors are kept running 24/7, right?

 

[stang8s]

depends on your calcium load. My tank has a low calcium load. On my 75 I have a 15 pound co2 tank that has been going over a year without a refill. My bubble rate is very slow though. Others with alot of sps will have a faster rate.

 

[Matt L.]

So the make up of the media is important since the media is totally dissolved and the product dripped into the tank. Whatever is in the media will get dripped into the tank, right?

Only sort of....

The media (calcium carbonate) we know is soluble (able to dossolve under the conditions in the reactor). What pollutants in the media you are concerned about have to be soluble too. If you were to throw regular granite rocks in the reactor, I don't think they'd ever dissolve.

Matt

 

[Moe_K]

I've heard Ca reactors are initially difficult to get set up and running. I've seen posts from folks having trouble "dialing it in."
How tough are these things to set up once you have one? How much maintenance do they require?

 

[Moe_K]

Only sort of....

The media (calcium carbonate) we know is soluble (able to dossolve under the conditions in the reactor). What pollutants in the media you are concerned about have to be soluble too. If you were to throw regular granite rocks in the reactor, I don't think they'd ever dissolve.

Matt

Good point, I'm glad you joined the discussion.
I've heard a theory that some media might contain phosphates (PO4). If that's true, could the phosphate be liberated, and then dripped into the tank?

 

[Jim Tansey]

I have a question I wish someone could answer, I have seen this stated many times that a Calcium reactor will not by itself increase Calcium levels, but when the Calcium levels are increased by the addition of Calcium Chloride or similar product it will maintain that level. Having recently set up a reactor this is exactly what happened, but I don't understand why it will not increase the Calcium by itself.

Jim

 

[Matt L.]

Good point, I'm glad you joined the discussion.
I've heard a theory that some media might contain phosphates (PO4)....

Yes, I have heard the same.

If that's true, could the phosphate be liberated, and then dripped into the tank?

Yes, but only if the phosphate is part of a compound that is soluble in the reactor. Otherwise, the phosphate would remain sequestered in an insoluble compound. I do not know enough about minerals and solubility to know off hand which ones would be soluble in a calcium reactor, although it could be figured out,

Matt

 

[Moe_K]

I've also read some posts about mixing "dolomite" in with reactor media. I think the idea was to liberate magnesium. Anyone remember more?

 

[Matt L.]

I have a question I wish someone could answer, I have seen this stated many times that a Calcium reactor will not by itself increase Calcium levels, but when the Calcium levels are increased by the addition of Calcium Chloride or similar product it will maintain that level.

Jim,

a calcium reactor adds calcium and alkalinity to your tank at the same time. If you just want to add calcium and not alkalinity, then yes, use calcium chloride.

If you find that your calcium reactor can not add anymore calcium, then your alkalinity is up probably as far as it goes. Is your alkalinity okay or high? If so, then to get your calcium levels in line, you may have to add calcium chloride to bump the calcium and not the alkalinity.

Dr. Randy wrote an article and has an excellent graph he drew showing how calcium and alkalinity are added together with a reactor (and with kalkwasser and with two-part additives).

Matt

 

[Matt L.]

I've also read some posts about mixing "dolomite" in with reactor media. I think the idea was to liberate magnesium. Anyone remember more?

Yes, but I had serious qualms about this approach. It can be (and maybe even has been succesfully) done, and is theoretically possible.

No one ever answered my question as to whether all the dolomite would dissolve first leaving undisolved calcium carbonate, or visa versa.

Also, remember that dissolving dolomite via a calcium-now-magnesium reactor will again raise your magnesium and alkalinity together, not just magnesium. So your magnesium can only go as high as alkalinity will permit at the expense of calcium that could be added (along with its alkalinity),

Matt