muzzy
29-07-07, 09:27
Setting up a Calcium Reactor
Running a successful tropical reef tank requires stable water parameters.
Two of the more important ones that you will probably have heard talked about a lot are Calcium and Alkalinity.
Why are these important?
Invertebrates such as Corals, shrimps and molluscs all require calcium and carbonate in the process of calcification - or basically they need these in order to grow.
It is a bit of a myth that if you run a soft coral only tank then you don't need to replenish calcium levels, this is not true, most soft corals do require calcium for healthy growth, although a lot less than a hard coral dominated tank.
Calcium reactors are an excellent way of replenishing calcium and alkalinity. Once set up they have very little ongoing costs, a decent size bag of media should last most reef keepers a year or more and a 2kg bottle of CO2 should keep you going for several months.
Apart from the occasional effluent testing and a bit of tweaking to the CO2 and/or drip rates to keep up with your growing corals calcium demands you can pretty much leave it to its own devices.
How does a Calcium Reactor Work?
Calcium reactors can vary from one manufacturer to the next, but they all work on the same principle, a chamber filled with calcium carbonate media (CaCO3), a supply feed of tank water and a supply feed of Carbon Dioxide (CO2) with a recirculating pump connected to the chamber.
By slowly feeding the chamber with tank water and mixing it with the CO2. This makes the pH of the water in the chamber lower which in turn dissolves the carbonate media releasing calcium and carbonate back into your tank.
What equipment do I need?
When choosing a calcium reactor it is important to know what you are getting in the box. Some manufacturers supply more kit than others, I have yet to find any manufacturer that supplies everything you need, or at least everything that I recommend you need to run a calcium reactor successfully with little fuss or problems.
The Reactor
Here are a few different models available at the time of writing this article. They all consist of a chamber for holding the media, a recirculating pump, input and outputs for the water and an input for the CO2. Most come with a bubble counter for visually inspecting the CO2 entering the reactor. However some models do not come with a bubble counter so I would recommend either purchasing one that comes with a bubble counter or buying a bubble counter separately (aqua medic for example sell one).
Also look for a reactor that comes with a pH probe holder, although not essential, it makes life a lot easier, this will be explained more further down.
http://www.ultimatereef.net/uploader/2007Q2/kr1000.jpg http://www.ultimatereef.net/uploader/2007Q2/PF501.gif
http://www.ultimatereef.net/uploader/2007Q2/HKR110.jpg http://www.ultimatereef.net/uploader/2007Q2/SC2453.jpg
The Media - Calcium Carbonate CaCO3
Like there are several types of reactors to choose from, there is also a choice on different media to choose!
The most popular ones used are Deltec Rowalith C+, Caribsea ARM Media or Coral Gravel/Reef Bones.
The commercially produced media all have there claims to be the best with the least amount of phosphates, the most amount of this that and the other, etc.
The commercial products all carry a hefty price tag compared to coral gravel. It is up to you to decide if you believe their claims, from my own experience I have found coral gravel more than up to the job and at around 500% cheaper in some cases.
It should be noted that it is likely all calcium carbonate media will contain some level of phosphates and it is advisable to run phosphate removers in any reef tank regardless of whether you use a calcium reactor or not.
http://www.ultimatereef.net/uploader/2007Q2/calcmedia.jpg
Different media will work better than others in some reactors. For example I have tried Rowalith C+ in my Grotech reactor and found that the pump was too powerful and was sucking the media into the pump. So I use coral gravel which is a lot heavier and doesn't "spin" around the chamber like the smaller and lighter media will. If your reactor has a sponge before the pump intake then this shouldn't be a problem however.
Also different media will require a lower or higher pH than others to start dissolving. You need to know what pH is required for your media and this should be stated on the packaging, generally it will be between 6.30 and 6.70 unless you have purchased raw coral gravel in which case I'd advise a starting pH of 6.20.
If you run the pH too low with any media then it will dissolve too quickly and cause the water in the reactor to turn into a milky white solution. If you run the pH too high then you won't be getting the full benefit from running a calcium reactor. This is why I recommend using a pH controller and probe (see further down!)
Carbon Dioxide - CO2
CO2 is required to reduce the pH in the reactor, as your reef tank is probably running at a pH of around 8.0 to 8.40 the water entering the reactor from your tank has too high a pH to dissolve the media which as stated above will only start giving you results at a pH of below 6.70.
CO2 can be dangerous stuff! However used correctly and following a few guidelines it is perfectly safe.
When connecting your regulator to the CO2 bottle, you should use PTFE tape on all threaded connections to ensure an airtight seal. Once everything is connected and turned on you should smear some soapy water on all your CO2 connections, if there is a leak the bubbles will grow in size in seconds which indicates a leak. This MUST be rectified by adding more PTFE tape and/or tightening the connections.
You should check these connections periodically with soapy water to ensure they stay sealed. CO2 is a clear and odourless gas that can act as an asphyxiant, always bare this in mind when working with CO2.
Your CO2 bottle should be firmly secured, if it falls over it is possible the collar can break off and the bottle will take off like a rocket!
High temperatures can also cause CO2 bottles to explode, keep this in mind when locating your bottle, don't place it next to a high heat source such as radiators or halide lamp ballasts, etc.
Finally, there are several options on CO2 bottles available, you can purchase small disposable bottles which cannot be refilled and standard size regulators will not fit these, so you should check with the supplier to see if you will need a special adaptor. The best source for CO2 is from a bottled drinks wholesaler, or a welding suppliers. Both of whom should be able to supply you with a decent sized bottle that will last a year or more and they also run refill and/or replacement facilities. You can also use CO2 Fire extinguishers, however you may have more difficulty getting these refilled as most welding suppliers will not refill these.
http://www.ultimatereef.net/uploader/2007Q2/disco2bottle.jpg http://www.ultimatereef.net/uploader/2007Q2/co2.jpg
Regulator / Gauges
Attached to the top of your CO2 bottle is the regulator.
This usually comprises of a dual gauge indicating the bottle pressure and the operating pressure.
Attached to the regulator will be a needle valve, this allows you to finely tune the amount of CO2 released from the bottle and this should read between 1.5 to 2 Bar. When purchasing your regulator you should check that it is capable of delivering this pressure. Any regulator designed for aquatics use should be fine.
http://www.ultimatereef.net/uploader/2007Q2/regulator.jpg
Solenoid Valve
The solenoid valve is an electrically operated switch that allows the CO2 to flow from the bottle to the reactor when the power is "ON". When the power is "OFF" the valve closes and stops the flow of CO2.
The solenoid valve is a crucial part of a correctly run calcium reactor. It allows you to control the CO2 addition to maintain a stable pH within the reactor.
You can run the solenoid off of a segment timer so that it is only on for a selected period of time - usually during the day. However this is not a very reliable method as it can be quite easy to overdose CO2 to the reactor causing the milky effluent I described earlier.
A more reliable method is to plug the solenoid into the output of a pH controller which will turn on and off the CO2 supply on demand as the pH rises or falls in the reactor.
http://www.ultimatereef.net/uploader/2007Q2/M-ventil.jpg
Bubble Counter
The bubble counter is a simple but important part of the set up, it is the only thing that allows you to see how much CO2 is entering the reactor. Too much CO2 and your reactor will turn milky (unless using a pH controller) not enough CO2 and your media will not be dissolving fast enough.
The bubble counter fits somewhere between the output of the CO2 bottle and the CO2 input to the reactor. Most reactors come with a bubble counter integrated within it, however if your does not you should fit one somewhere along this line in an upright position and ideally below the height of the solenoid valve to prevent water siphoning back into the solenoid. You should always fit an anti-siphon check valve after the solenoid for peace of mind in any case.
http://www.ultimatereef.net/uploader/2007Q2/bubblecounter.jpg
pH Controller
The pH controller does what it says on the tin! It keeps the pH to a pre-determined set level within the reactor. Depending on your media type used will depend on the pH level required. Typically between 6.20 and 6.70.
Assuming you have purchased a calcium reactor with a pH probe holder in the lid, insert your pre-calibrated probe into the reactor and connect to the controller. Plug your solenoid valve into the output of the controller and run tank water through the reactor at a rate of about 60 drips per minute (see further down) then turn on your pH controller and gradually turn the needle valve on your regulator until a bubble rate of around 40 per minute is achieved.
Now leave it alone for 24 hours!
After this period you should be getting a relatively stable pH of your pre set choice within the reactor. You can now test the effluent coming out to see if you are achieving enough alkalinity (Dkh) to keep up with your tanks demand. More on that later.
http://www.ultimatereef.net/uploader/2007Q2/pHcontroller.jpg
Water Supply
You need to get tank water going into the reactor and out at a constant rate to achieve stable reliable addition of calcium and alkalinity.
The best way to do this is to use a variable speed peristaltic pump. You can then easily fine tune the amount of effluent produced and increase or decrease as is necessary.
Other methods are to take a T off of a pump such as your sump return or to use a gravity fed siphon, however both these methods can produce an unreliable drip rate.
http://www.ultimatereef.net/uploader/2007Q2/peri.jpg
continued...
Running a successful tropical reef tank requires stable water parameters.
Two of the more important ones that you will probably have heard talked about a lot are Calcium and Alkalinity.
Why are these important?
Invertebrates such as Corals, shrimps and molluscs all require calcium and carbonate in the process of calcification - or basically they need these in order to grow.
It is a bit of a myth that if you run a soft coral only tank then you don't need to replenish calcium levels, this is not true, most soft corals do require calcium for healthy growth, although a lot less than a hard coral dominated tank.
Calcium reactors are an excellent way of replenishing calcium and alkalinity. Once set up they have very little ongoing costs, a decent size bag of media should last most reef keepers a year or more and a 2kg bottle of CO2 should keep you going for several months.
Apart from the occasional effluent testing and a bit of tweaking to the CO2 and/or drip rates to keep up with your growing corals calcium demands you can pretty much leave it to its own devices.
How does a Calcium Reactor Work?
Calcium reactors can vary from one manufacturer to the next, but they all work on the same principle, a chamber filled with calcium carbonate media (CaCO3), a supply feed of tank water and a supply feed of Carbon Dioxide (CO2) with a recirculating pump connected to the chamber.
By slowly feeding the chamber with tank water and mixing it with the CO2. This makes the pH of the water in the chamber lower which in turn dissolves the carbonate media releasing calcium and carbonate back into your tank.
What equipment do I need?
When choosing a calcium reactor it is important to know what you are getting in the box. Some manufacturers supply more kit than others, I have yet to find any manufacturer that supplies everything you need, or at least everything that I recommend you need to run a calcium reactor successfully with little fuss or problems.
The Reactor
Here are a few different models available at the time of writing this article. They all consist of a chamber for holding the media, a recirculating pump, input and outputs for the water and an input for the CO2. Most come with a bubble counter for visually inspecting the CO2 entering the reactor. However some models do not come with a bubble counter so I would recommend either purchasing one that comes with a bubble counter or buying a bubble counter separately (aqua medic for example sell one).
Also look for a reactor that comes with a pH probe holder, although not essential, it makes life a lot easier, this will be explained more further down.
http://www.ultimatereef.net/uploader/2007Q2/kr1000.jpg http://www.ultimatereef.net/uploader/2007Q2/PF501.gif
http://www.ultimatereef.net/uploader/2007Q2/HKR110.jpg http://www.ultimatereef.net/uploader/2007Q2/SC2453.jpg
The Media - Calcium Carbonate CaCO3
Like there are several types of reactors to choose from, there is also a choice on different media to choose!
The most popular ones used are Deltec Rowalith C+, Caribsea ARM Media or Coral Gravel/Reef Bones.
The commercially produced media all have there claims to be the best with the least amount of phosphates, the most amount of this that and the other, etc.
The commercial products all carry a hefty price tag compared to coral gravel. It is up to you to decide if you believe their claims, from my own experience I have found coral gravel more than up to the job and at around 500% cheaper in some cases.
It should be noted that it is likely all calcium carbonate media will contain some level of phosphates and it is advisable to run phosphate removers in any reef tank regardless of whether you use a calcium reactor or not.
http://www.ultimatereef.net/uploader/2007Q2/calcmedia.jpg
Different media will work better than others in some reactors. For example I have tried Rowalith C+ in my Grotech reactor and found that the pump was too powerful and was sucking the media into the pump. So I use coral gravel which is a lot heavier and doesn't "spin" around the chamber like the smaller and lighter media will. If your reactor has a sponge before the pump intake then this shouldn't be a problem however.
Also different media will require a lower or higher pH than others to start dissolving. You need to know what pH is required for your media and this should be stated on the packaging, generally it will be between 6.30 and 6.70 unless you have purchased raw coral gravel in which case I'd advise a starting pH of 6.20.
If you run the pH too low with any media then it will dissolve too quickly and cause the water in the reactor to turn into a milky white solution. If you run the pH too high then you won't be getting the full benefit from running a calcium reactor. This is why I recommend using a pH controller and probe (see further down!)
Carbon Dioxide - CO2
CO2 is required to reduce the pH in the reactor, as your reef tank is probably running at a pH of around 8.0 to 8.40 the water entering the reactor from your tank has too high a pH to dissolve the media which as stated above will only start giving you results at a pH of below 6.70.
CO2 can be dangerous stuff! However used correctly and following a few guidelines it is perfectly safe.
When connecting your regulator to the CO2 bottle, you should use PTFE tape on all threaded connections to ensure an airtight seal. Once everything is connected and turned on you should smear some soapy water on all your CO2 connections, if there is a leak the bubbles will grow in size in seconds which indicates a leak. This MUST be rectified by adding more PTFE tape and/or tightening the connections.
You should check these connections periodically with soapy water to ensure they stay sealed. CO2 is a clear and odourless gas that can act as an asphyxiant, always bare this in mind when working with CO2.
Your CO2 bottle should be firmly secured, if it falls over it is possible the collar can break off and the bottle will take off like a rocket!
High temperatures can also cause CO2 bottles to explode, keep this in mind when locating your bottle, don't place it next to a high heat source such as radiators or halide lamp ballasts, etc.
Finally, there are several options on CO2 bottles available, you can purchase small disposable bottles which cannot be refilled and standard size regulators will not fit these, so you should check with the supplier to see if you will need a special adaptor. The best source for CO2 is from a bottled drinks wholesaler, or a welding suppliers. Both of whom should be able to supply you with a decent sized bottle that will last a year or more and they also run refill and/or replacement facilities. You can also use CO2 Fire extinguishers, however you may have more difficulty getting these refilled as most welding suppliers will not refill these.
http://www.ultimatereef.net/uploader/2007Q2/disco2bottle.jpg http://www.ultimatereef.net/uploader/2007Q2/co2.jpg
Regulator / Gauges
Attached to the top of your CO2 bottle is the regulator.
This usually comprises of a dual gauge indicating the bottle pressure and the operating pressure.
Attached to the regulator will be a needle valve, this allows you to finely tune the amount of CO2 released from the bottle and this should read between 1.5 to 2 Bar. When purchasing your regulator you should check that it is capable of delivering this pressure. Any regulator designed for aquatics use should be fine.
http://www.ultimatereef.net/uploader/2007Q2/regulator.jpg
Solenoid Valve
The solenoid valve is an electrically operated switch that allows the CO2 to flow from the bottle to the reactor when the power is "ON". When the power is "OFF" the valve closes and stops the flow of CO2.
The solenoid valve is a crucial part of a correctly run calcium reactor. It allows you to control the CO2 addition to maintain a stable pH within the reactor.
You can run the solenoid off of a segment timer so that it is only on for a selected period of time - usually during the day. However this is not a very reliable method as it can be quite easy to overdose CO2 to the reactor causing the milky effluent I described earlier.
A more reliable method is to plug the solenoid into the output of a pH controller which will turn on and off the CO2 supply on demand as the pH rises or falls in the reactor.
http://www.ultimatereef.net/uploader/2007Q2/M-ventil.jpg
Bubble Counter
The bubble counter is a simple but important part of the set up, it is the only thing that allows you to see how much CO2 is entering the reactor. Too much CO2 and your reactor will turn milky (unless using a pH controller) not enough CO2 and your media will not be dissolving fast enough.
The bubble counter fits somewhere between the output of the CO2 bottle and the CO2 input to the reactor. Most reactors come with a bubble counter integrated within it, however if your does not you should fit one somewhere along this line in an upright position and ideally below the height of the solenoid valve to prevent water siphoning back into the solenoid. You should always fit an anti-siphon check valve after the solenoid for peace of mind in any case.
http://www.ultimatereef.net/uploader/2007Q2/bubblecounter.jpg
pH Controller
The pH controller does what it says on the tin! It keeps the pH to a pre-determined set level within the reactor. Depending on your media type used will depend on the pH level required. Typically between 6.20 and 6.70.
Assuming you have purchased a calcium reactor with a pH probe holder in the lid, insert your pre-calibrated probe into the reactor and connect to the controller. Plug your solenoid valve into the output of the controller and run tank water through the reactor at a rate of about 60 drips per minute (see further down) then turn on your pH controller and gradually turn the needle valve on your regulator until a bubble rate of around 40 per minute is achieved.
Now leave it alone for 24 hours!
After this period you should be getting a relatively stable pH of your pre set choice within the reactor. You can now test the effluent coming out to see if you are achieving enough alkalinity (Dkh) to keep up with your tanks demand. More on that later.
http://www.ultimatereef.net/uploader/2007Q2/pHcontroller.jpg
Water Supply
You need to get tank water going into the reactor and out at a constant rate to achieve stable reliable addition of calcium and alkalinity.
The best way to do this is to use a variable speed peristaltic pump. You can then easily fine tune the amount of effluent produced and increase or decrease as is necessary.
Other methods are to take a T off of a pump such as your sump return or to use a gravity fed siphon, however both these methods can produce an unreliable drip rate.
http://www.ultimatereef.net/uploader/2007Q2/peri.jpg
continued...