How does it work? Vol 2: Ca reactors

[Jim Tansey]

Matt,

My question is not so much to do with my tank as Ca & Alk are fine now, its a general question. When I was setting up my reactor I was told, and read prior to this, that the desired tank Ca and Alk must be adjusted with additives THEN THE REACTOR CAN MAINTAIN THESE READINGS. In my case I adjusted the Alk to about 8.5 dKH started the reactor and my Ca never moved from its initial reading of 325 even with an effluent pH of near 7. When I adjusted with Calcium Chloride to 420 (alk 8.5 dKH) it has stayed at these exact readings for three weeks. I just wonder why it can maintain a good Ca level but could not bring it up there.

Jim

 

[nunofs]

Jim, I think what's happening is that your reactor is delivering exactly the amount of Ca that your corals are using up, that's why you don't see it change, the reactor simply maintains the level that existed beforehand.

Nuno

 

[Chuck Spyropulos]

Calcium reactors use a reaction tube, or even two reaction tubes to hold media that is rich in calcium carbonates. In order to get the calcium, carbonates and other trace elements from the media, water is injected, along with carbon dioxide into the reaction tubes. The water and the C02 form a weak carbonic acid that slowly dissolves the media. This is enhanced by the recirulation pump such that the fluid in the first of the two media chambers becomes richer and richer in calcium, carbonates and other minerals and trace elements. This fluid is then dripped into a sump in order to add calcium (for calcium supplementation) and carbonates and bicarbonates (for alkalinity supplementation) as well as trace elemnets to the aquarium. The reason for the second chamber is to remove any excess CO2 that would otherwise escape into the aquarium, which could cause an algal bloom but is not absolutely required, although it is recommended.

No calcium reactor, by itself, can bring a tank's calcium and alkalinity from really low levels to acceptable levels (See Randy Farley Holmes' papers on the acceptable levels). These reactors can only maintain levels at the desired operating point, which is another way of saying that the reactor can only produce enough calcium and alkalinity in order to cancel out what the corals and other animals consume.

You therefore must get your levels close to where you want them and then use the reactor to maintian these levels. Calcium Chloride is used to supplement Calcium and Kalkwasser is used to increase alkalinity.

These reactors, used alone, can decrease pH while at the same time increasing calcium and alkalinity. I use a kalkwasser reactor in my water topoff loop to maintain a steady pH since these reactors tend to raise pH. I only need to do this at night when the pH of my tank runs lower. The reason that pH runs lower at night is that the animals do not consume CO2 at the same rate that they do during the "lights on" period. The xooanthellae in the coral tissues are not using up excess C02 for photosynthesis at night so any excess CO2 will lower pH. In the "lights on" period the corals do use up the C02 and so the pH is "naturally" boosted and runs around 8,35 in my tank.

 

[Aquadiva]

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?

Did this ever get answered? I think we went from Intro to Ca Reactors right to Ca Reactor 401. Surprisingly enough I am following this, but I am confused why anyone would use a one chamber reactor? Seems it would wreak havoc on the PH, especially at night.

 

[ScottM]

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?

Quite the opposite.
A lot of the reactors out there that range in price also range in adjustability.

The change is slow so it may take a few days to get it set. Dialing it in is a combination of setting your bubble count (usually start off with 1 per second) and your effluent flow. My reactor has a meter on it that measures this for me with the turn of a knob. Most have to measure using a container.
An alternative is to check the PH. you PH should be between 6.5 and 7.3

Wait at least 24hrs and measure you effluent CA and ALK. Match you reactor to your dosing requirements. If you dose x ml that raises your level y then make sure your reactor effluent is:
Current tank param + Y = effluent
This is just a guideline to start.




I can't stress enough that the KEY is to have your levels up with dosing and then run your reactor to maintain. I lost a whole tank to low levels.

 

[Moe_K]

Okay, if anyone wants to address any of the posts made previously, please feel free to do so. This is going well.

Lets throw in a new talking point: what should somebody who is new to Ca reactors look for when trying to decide which model they should buy? and how much should a customer look to pay?
Hold off on DIY - that comes in the next section.

 

[Chuck Spyropulos]

Ca Reactor Set up

The easiest way to set one up is to first set the drip rate according to your tank size and the calcium reactor directions.
Then you need to adjust the C02 until the output liquid reaches a pH of around 6 to 7.....this depends on the type of media(some are more soluble than others), size of your tank (determines the amount of calcium and alk), number and type of corals (SPS require more calcium than most others).

A great way to keep the output at the same pH is to use a solenoid valve with your C02 setup. This valve can then be controlled via a pH controller that measures the output pH ,via a probe plumbed at the output of the reactor,and turns the C02 on when the pH gets too high and turns it off when it gets too low.

Example: Let's say that you want to keep your reactor output pH at 6.8. Now you determine from reading the calcium reactor insructions that you need 60 ml per hour drip rate. Don't worry about these numbers now...I will explain them later.

With or without a pH controller you would need to adjust the output so that you get 6o ml per hour of output from the reactor into your sump. That translates into 1 ml per minute. So you need to first guess at how to set your output valve on your reactor. Now fill up a container (with a ml scale on it) and time how long it takes to fill the container up to 1 ml. If it takes more than a minute you need to open the valve. If it takes less than a minute then you need to close the valve slightly. You need to repeat this until it takes precisely 1 minute to fill up the container with 1 ml of fluid.

Once the flow rate is set, you need to adjust the C02. If you have a pH controlled solenoid valve then you set the pH controller to 6.8 and you are done. If you do not have a controlled solenoid valve then you need to adjust the amount of CO2 by meesuring the pH of the output over a period of time until it remains constant. This can be done by using a ph monitior with its probe plumbed in the output pipe/hose and continually adjusting the C02 valve until the output pH remains constant over a day or 2.

OK so how do you find the flowrate and the output pH you need ? Well the required pH is less sensitive to the size of tank or the number of corals. It depends more on the solubility of the calcium reactor media...some types disolve at 6.8 some at 6.5... but a general rule of thumb is to keep it around 6.5.

The flowrate depends on the tank size and number/type of coral. I think the best way to determine the required flowrate is first, use the suggested flowrates in t he instructions that came with your unit. Then measure calcium and alklinity every day or two and decrease or increase the flow until you maintain the desired numbers.

Now, if your reactor output valve is open all the way (maximum flow) and you still can't maintain your calcium and alk requirements, then and only then should you reduce the output pH by opening the CO2 valve slightly an either monitor the pH or control it with the pH controller.
This happened to me....I had a small reactor for my 300 gallon tank and it was cranked wide open but I could not meet my calcium and alk demands....even after I lowered my output pH to 6.0! I needed a bigger reactor and once I got my MRC reactor I caould meet the demands of my tank. My flowrate out of the rector is still max (output valve wide open) and my output pH is controlled to around 6.5. Be advised that these numbers will be different for different tanks. Questions ?

Did this ever get answered? I think we went from Intro to Ca Reactors right to Ca Reactor 401. Surprisingly enough I am following this, but I am confused why anyone would use a one chamber reactor? Seems it would wreak havoc on the PH, especially at night.

 

[Chuck Spyropulos]

Come on someone must have questions....I love to teach so please ask me questions ! If I could make a living teaching, I would do it in a second...but....engineering pays the bills better and allows me to keep my tank as well as my calcium reactor

 

[ScottM]

what should somebody who is new to Ca reactors look for when trying to decide which model they should buy? and how much should a customer look to pay?

I have a Pro Cal by MTC.
http://www.marinetechnical.com/

I love it. a bit pricy at 695.00 new.
some key things that make it worth the $$ to me is:
calibrated glass flow meter, needle valve, PSI pressure gauge, and a Precision built-in C02 override assembly. keeps excessive C02 out of the tank and keeps the chambers from building too much pressure if media is clogged.

Geo http://www.homestead.com/geosreef/index.html
barr http://barraquatic.com/cal.php
MRC http://www.myreefcreations.com/
KR2
H&S https://ssl.perfora.net/oeaonline.com/sess/utn;jsessionid=1541ca1d3473f68/shopdata/index.shopscript

Schuran http://www.schuran.com/seawater/hobby_e.html


are a few other choice brands

 

[Chuck Spyropulos]

I have an MRC and I love it ! Since I run mine full throttle I don't need a calibrated glass flow meter, but this sounds like a GREAT accessory !

 

[ScottM]

I often get the question:

I put a reactor on my tank and I can't keep my PH at 8.4 anymore. what should i do?

chuck....

 

[Chuck Spyropulos]

answer

One option is to dose kalkwasser to help keep the pH higher. Another is to increase the pH of the output effluent from the Ca reactor....but this might compromise Ca levels especially if the reactor is undersized...this was the case with my first reactor.

I often get the question:

I put a reactor on my tank and I can't keep my PH at 8.4 anymore. what should i do?

chuck....

 

[Chuck Spyropulos]

Hey Scott, with my new fishroom my pH was getting as high as 8.6!
So I adjusted my Ca reactor's output effluent pH to around 6.0 to keep my pH down! This is especially pronounced using the pickling lime instead of the calcium hydroxide and is even more pronounced when I first fill up my kalkreactor with kalk. Any ideas ?

 

[Calciumbuf]

No calcium reactor, by itself, can bring a tank's calcium and alkalinity from really low levels to acceptable levels (See Randy Farley Holmes' papers on the acceptable levels). These reactors can only maintain levels at the desired operating point, which is another way of saying that the reactor can only produce enough calcium and alkalinity in order to cancel out what the corals and other animals consume.

Chuck ,I have to disagree with you on this statement. If the reactor itself is large enough for the system it is supplying and the effluent rate and co2 rate surpass the demand of the system it is quite capable of increasing the alkalinity and calcium in the system,but only in equal porportions. It would not per say balance the system , those adjustments would need to made manually. What you goal would be is to adjust the reactor so that it only supplies what your daily tank demand is no more no less.

 

[Chuck Spyropulos]

Calcium and Alk

You could be right, depending on the size of the reactor. My Calcium Reactor instructions state unequivocally (sp?) that "No reactor can provide all the calcium required". Perhaps it should have stated that " No calcium reactor can provide the required balanced calcium and alkalinity without any manual adjustment whatsoever"

But, I guess if you had a really large reactor, you could do it. Has anyone been able to raise their calcium from really low to around 450 without adding calcium in any other form (kalkwasser, calcium chloride, etc) ?

No calcium reactor, by itself, can bring a tank's calcium and alkalinity from really low levels to acceptable levels (See Randy Farley Holmes' papers on the acceptable levels). These reactors can only maintain levels at the desired operating point, which is another way of saying that the reactor can only produce enough calcium and alkalinity in order to cancel out what the corals and other animals consume.

Chuck ,I have to disagree with you on this statement. If the reactor itself is large enough for the system it is supplying and the effluent rate and co2 rate surpass the demand of the system it is quite capable of increasing the alkalinity and calcium in the system,but only in equal porportions. It would not per say balance the system , those adjustments would need to made manually. What you goal would be is to adjust the reactor so that it only supplies what your daily tank demand is no more no less.

 

[Calciumbuf]

Chuck I actually do this very thing to control my alk and cal, I have gotten so good at it that I never really use supplements unless correcting an imbalance. And in my opinion doing it with a reactor "although a bit more complicated and not for a novice" is a more gradual adjustment and less shocking than with supplements. I would definately have to say that those instructions are grossly incorrect in that sense.

 

[Chuck Spyropulos]

Calciumbuf,

Yes, I agree that a reactor is much better than simply dumping in supplements. However, for a small system, Alk and Calcium can be controlled via gradual dosing of balanced additives such as the Bionic 2 -part balanced additives. In this case a calcium reactor might be overkill.

 

[Aquadiva]

I have a Pro Cal by MTC.
http://www.marinetechnical.com/

some key things that make it worth the $$ to me is:
calibrated glass flow meter, needle valve, PSI pressure gauge, and a Precision built-in C02 override assembly. keeps excessive C02 out of the tank and keeps the chambers from building too much pressure if media is clogged.

Sorry guys, moving back towards Intro to Ca Reactors.

What exactly does the above stuff do? Are any of them more important than others? ie. Don't buy one without ....... (fill in the blank). Also, can you use the manufactures recommendations when purchasing one for your size tank. I find that most of the recommendations on protein skimmers are exaggerated.

 

[Moe_K]

New folks, please feel free to jump in with questions!

 

[Calciumbuf]

Yes, Agreed, A smaller system with a lesser demand for calcium and alkalinty might actually suffer from a reactor in the sense that it could be much more difficult to dial in at such a low demand thus creating swings which could lead to overall poor tank conditions.