ca1ore
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Building a Large, Modular Calcium Reactor
I have long cited a calcium reactor (CaRx) as THE piece of equipment that got me over the hump with SPS. That was back in 1997, and the reactor was a Marine Technical Concepts ProCal. Those who may be familiar with my posts know I am an unabashed fan of MTC gear; and have used their stuff successfully and reliably for over 25 years. Times change, and while my enthusiasm for their gear remains undiminished, the actual company is now retired. I've had them build modifications for me over the years, both for the ProCal and my various MTC skimmers, but now it's up to me. I like to build stuff, though my relative expertise skews more to wood than it does acrylic or glass. How hard can it be?
Retired after 21 years (17 operational). Folks can debate what constitutes 'best,' but reliability and longevity will take the day for me every time.
My initial disclaimer is that there are plenty of good commercial options for a CaRx. For most, a commercial option will suffice. In my case, I enjoy a project and I wanted something that exceeded the dimensions of the reasonably priced options. I also liked the idea of a modular system where different canisters could be swapped in based on need.
Some may have seen my article on building a glass algal turf scrubber; here I will detail my efforts to make a large, modular calcium reactor. I feel that I'm at the upper limit of the MTC ProCal, and nothing commercially available really sparks my fancy. There is nothing necessarily wrong with those options, just that for a 700-gallons system (and bigger in the future perhaps) they get expensive. Not that buying raw acrylic tube in larger diameters is necessarily cheap, but it is cheaper. I'm going to go overboard here, so bear with me.
My current primary rubble chamber holds about 500 cubic inches or media (I use reborn), and my goal is to essentially double the capacity to 1,000 cubic inches. I like the idea of triple chambers – chamber one to ensure complete dissolution of CO2, chamber two to hold the main media, and chamber three to scrub out any residual CO2. I shall continue to use the current Panworld PX40 as the circulation pump and a basic masterflex in pull mode as the effluent pump. The first chamber will be down-flow, the other two up-flow.
Machining acrylic is really quite simple. Sophisticated acrylic fabrication houses will have CNC machines; I'm constrained to routers and jigs. Fine for low volume, hobby-scale production; problematic for larger scale efforts.
To cut the circles and flanges I'm using a Jasper circle jig, a Ryobi trim router and upcut spiral router bits. Hole saws for small diameter circles. Threaded holes are accomplished with standard NPT tap sets. I've been buying the cast acrylic tube from ePlastics, in varied diameters but always 1/4" thick walls. I have them cut the tube to the length that I need because accurately cutting larger tubing would be tricky for me. The tube comes with square cuts and smooth edges. No problems with gluing. The bases, tops and flanges are machined from 1/2" thick black cast acrylic sheet. Although some may demur, I prefer to use the thickened cement (Weldon 16). Joint strength seems broadly equivalent, but it is much easier to work with. You don’t get a completely bubble-free joint, but these are reactors and will quickly get schmutzed up from use anyhow, so the aesthetics are secondary to me.
Power tools, particularly routers, 'terrify' me so I am cautious and careful. If you are not experienced with these kinds of tools, don’t try it. If you are experienced, still observe safety procedures. I always use safety glasses, hearing protection and a dust mask. Make sure your work area is clean and clear and that you balance your feet to avoid being knocked of balance in the event the router kicks. Take small amounts of material off stock with multiple passes. This reduces any material burn and helps to preserve the life of your router and bits.
Main Rubble Chamber
The main chamber will have an 8" outer diameter (OD) tube with 1/4" thick walls at 24" tall. Adjusted for a bottom retainer plate and some inevitable head space at the top, this will hold about 1,000 cubic inches of media. I use reborn, so this means something like 3/4 of the large box they sell.
Pictures will convey the details better than words, but essentially I routed a groove into the 1/2" thick base to precisely accept the 8" tube. A bead of thickened cement into the groove sets in the cylinder. I always use 1/2" blocks of acrylic to reinforce lower joins. I don’t like boring holes in the sides, so the water in/out is though the flat bottom and top. Four posts inside the bottom provide the base for the dispersion plate. Post in the middle of the plate allows it to be easily removed for cleaning. I routed a dado into the top flange so that the welding surface is not just the face of the tube but also part of the side.
Holes in the flange are threaded to 1/4 inch by 20 (not NPT) to accept standard 1/4" nylon bolts. I like the red, thicker gasket material personally – it’s a bit more forgiving compared to the thin black material, plus it doesn't stink. The top lid for this chamber requires three holes: 3/4" slip bulkhead for the main circulation between this and the CO2 chamber, 1/2" NPT for the pH probe and 1/8" NPT for the 1/4" RO-style tubing that will link to the secondary scrubbing chamber.
CO2 Reactor Chamber
The initial CO2 mixing chamber will be 6" OD with 1/4" thick walls and 26" tall. I will fill this with approximately 3 gallons of bio-balls to ensure complete mixing of the gas. I don’t have to make the cylinder because it is my current rubble chamber, though I will need to modify the top lid. The water circulation will be out through the bottom, with main circulation pump between this and the main chamber. I've modified the lid for a number of holes: 3/4" slip bulkhead for the main circulation between this and the CO2 chamber, 1/4" NPT threaded for pressure gauge, 1/4" NPT for gas vent and then 1/8" NPT for input CO2. I like the visual effect of a bubble counter, so made one out of 2" acrylic tube with black 1/2" ends.
Secondary Scrubbing Chamber
The third chamber will be 5" OD with 1/4" thick walls, also 24" tall. I have historically used the Caribsea fine media, though that has been discontinued. Not an issue since it's essentially coarse coral substrate anyhow. New secondary cylinder will hold approximately 375 cubic inches of media. Same building process as the main rubble chamber. Input is a 1/8" NPT through the bottom; output is 1/8" NPT through a flow meter to the MasterFlex pump.
Plumbing
The PanWorld PX40 is native 3/4" so all circulation plumbing is also 3/4". I am using a 1" apex flow meter in the circuit to monitor and alert flow. Initial flow is nominally 400 GPH, but as the media clogs, flow gets reduced which can be a useful alert--though running the main rubble chamber up-flow helps to mitigate this significantly.
I have included a drain valve on the CO2 mixing chamber to facilitate draining for cleaning. Since the reactor will sit a few feet below the input water, the system runs at slightly positive pressure. This helps to ensure completed dissolution of the CO2 and prevents gas buildup. If I do get any of the latter, I can just open up the venting line.
Hooked the unit up this past weekend, thus retiring the old ProCal. Located it in an easier-to-access spot in my sump room. There were the inevitable plumbing leaks/drips, but those are easily handled. Incidentally, the now vacated spot for the old unit is a perfect spot of the new Apex Trident. How convenient…now I just have to be able to get one.
For the last decade, I have run my CaRx continuously--pausing only to periodically cycle the CO2 solenoid. I think long-term CaRx users, of whom there are a few, have mostly converged around this continuous approach--it avoids the swings inherent in pH-controlled units. I do have a pH probe in this unit--though for emergencies rather than iterative control.
So far, so good. Will have to dial this one in all over again, but that shouldn't be a problem. This CaRx should easily handle my current system, as well as any future enlargements.
~~~~~~~~~~~~
The photos in this article are all courtesy of @ca1ore ©2019, All Rights Reserved.
~~~~~~~~~~~~
We encourage all our readers to join the Reef2Reef forum. It’s easy to register, free, and reefkeeping is much easier and more fun in a community of fellow aquarists. We pride ourselves on a warm and family-friendly forum where everyone is welcome. You will also find lots of contests and giveaways with our sponsors.
~~~~~~~~~~~~
Author Profile: Simon Ellis or ca1ore on the forum.
Simon has over 20 years of experience with saltwater aquariums. He has experienced first-hand the changes in technology through the years, and is happy to share his vast knowledge with us here. Simon will be featured in a Profile of a Reef Aquarist coming up soon.
~~~~~~~~~~~~
Building a Large, Modular Calcium Reactor
I have long cited a calcium reactor (CaRx) as THE piece of equipment that got me over the hump with SPS. That was back in 1997, and the reactor was a Marine Technical Concepts ProCal. Those who may be familiar with my posts know I am an unabashed fan of MTC gear; and have used their stuff successfully and reliably for over 25 years. Times change, and while my enthusiasm for their gear remains undiminished, the actual company is now retired. I've had them build modifications for me over the years, both for the ProCal and my various MTC skimmers, but now it's up to me. I like to build stuff, though my relative expertise skews more to wood than it does acrylic or glass. How hard can it be?
Retired after 21 years (17 operational). Folks can debate what constitutes 'best,' but reliability and longevity will take the day for me every time.
My initial disclaimer is that there are plenty of good commercial options for a CaRx. For most, a commercial option will suffice. In my case, I enjoy a project and I wanted something that exceeded the dimensions of the reasonably priced options. I also liked the idea of a modular system where different canisters could be swapped in based on need.
Some may have seen my article on building a glass algal turf scrubber; here I will detail my efforts to make a large, modular calcium reactor. I feel that I'm at the upper limit of the MTC ProCal, and nothing commercially available really sparks my fancy. There is nothing necessarily wrong with those options, just that for a 700-gallons system (and bigger in the future perhaps) they get expensive. Not that buying raw acrylic tube in larger diameters is necessarily cheap, but it is cheaper. I'm going to go overboard here, so bear with me.
My current primary rubble chamber holds about 500 cubic inches or media (I use reborn), and my goal is to essentially double the capacity to 1,000 cubic inches. I like the idea of triple chambers – chamber one to ensure complete dissolution of CO2, chamber two to hold the main media, and chamber three to scrub out any residual CO2. I shall continue to use the current Panworld PX40 as the circulation pump and a basic masterflex in pull mode as the effluent pump. The first chamber will be down-flow, the other two up-flow.
To cut the circles and flanges I'm using a Jasper circle jig, a Ryobi trim router and upcut spiral router bits. Hole saws for small diameter circles. Threaded holes are accomplished with standard NPT tap sets. I've been buying the cast acrylic tube from ePlastics, in varied diameters but always 1/4" thick walls. I have them cut the tube to the length that I need because accurately cutting larger tubing would be tricky for me. The tube comes with square cuts and smooth edges. No problems with gluing. The bases, tops and flanges are machined from 1/2" thick black cast acrylic sheet. Although some may demur, I prefer to use the thickened cement (Weldon 16). Joint strength seems broadly equivalent, but it is much easier to work with. You don’t get a completely bubble-free joint, but these are reactors and will quickly get schmutzed up from use anyhow, so the aesthetics are secondary to me.
Power tools, particularly routers, 'terrify' me so I am cautious and careful. If you are not experienced with these kinds of tools, don’t try it. If you are experienced, still observe safety procedures. I always use safety glasses, hearing protection and a dust mask. Make sure your work area is clean and clear and that you balance your feet to avoid being knocked of balance in the event the router kicks. Take small amounts of material off stock with multiple passes. This reduces any material burn and helps to preserve the life of your router and bits.
Main Rubble Chamber
The main chamber will have an 8" outer diameter (OD) tube with 1/4" thick walls at 24" tall. Adjusted for a bottom retainer plate and some inevitable head space at the top, this will hold about 1,000 cubic inches of media. I use reborn, so this means something like 3/4 of the large box they sell.
Pictures will convey the details better than words, but essentially I routed a groove into the 1/2" thick base to precisely accept the 8" tube. A bead of thickened cement into the groove sets in the cylinder. I always use 1/2" blocks of acrylic to reinforce lower joins. I don’t like boring holes in the sides, so the water in/out is though the flat bottom and top. Four posts inside the bottom provide the base for the dispersion plate. Post in the middle of the plate allows it to be easily removed for cleaning. I routed a dado into the top flange so that the welding surface is not just the face of the tube but also part of the side.
Holes in the flange are threaded to 1/4 inch by 20 (not NPT) to accept standard 1/4" nylon bolts. I like the red, thicker gasket material personally – it’s a bit more forgiving compared to the thin black material, plus it doesn't stink. The top lid for this chamber requires three holes: 3/4" slip bulkhead for the main circulation between this and the CO2 chamber, 1/2" NPT for the pH probe and 1/8" NPT for the 1/4" RO-style tubing that will link to the secondary scrubbing chamber.
CO2 Reactor Chamber
The initial CO2 mixing chamber will be 6" OD with 1/4" thick walls and 26" tall. I will fill this with approximately 3 gallons of bio-balls to ensure complete mixing of the gas. I don’t have to make the cylinder because it is my current rubble chamber, though I will need to modify the top lid. The water circulation will be out through the bottom, with main circulation pump between this and the main chamber. I've modified the lid for a number of holes: 3/4" slip bulkhead for the main circulation between this and the CO2 chamber, 1/4" NPT threaded for pressure gauge, 1/4" NPT for gas vent and then 1/8" NPT for input CO2. I like the visual effect of a bubble counter, so made one out of 2" acrylic tube with black 1/2" ends.
Secondary Scrubbing Chamber
The third chamber will be 5" OD with 1/4" thick walls, also 24" tall. I have historically used the Caribsea fine media, though that has been discontinued. Not an issue since it's essentially coarse coral substrate anyhow. New secondary cylinder will hold approximately 375 cubic inches of media. Same building process as the main rubble chamber. Input is a 1/8" NPT through the bottom; output is 1/8" NPT through a flow meter to the MasterFlex pump.
Plumbing
The PanWorld PX40 is native 3/4" so all circulation plumbing is also 3/4". I am using a 1" apex flow meter in the circuit to monitor and alert flow. Initial flow is nominally 400 GPH, but as the media clogs, flow gets reduced which can be a useful alert--though running the main rubble chamber up-flow helps to mitigate this significantly.
I have included a drain valve on the CO2 mixing chamber to facilitate draining for cleaning. Since the reactor will sit a few feet below the input water, the system runs at slightly positive pressure. This helps to ensure completed dissolution of the CO2 and prevents gas buildup. If I do get any of the latter, I can just open up the venting line.
Hooked the unit up this past weekend, thus retiring the old ProCal. Located it in an easier-to-access spot in my sump room. There were the inevitable plumbing leaks/drips, but those are easily handled. Incidentally, the now vacated spot for the old unit is a perfect spot of the new Apex Trident. How convenient…now I just have to be able to get one.
For the last decade, I have run my CaRx continuously--pausing only to periodically cycle the CO2 solenoid. I think long-term CaRx users, of whom there are a few, have mostly converged around this continuous approach--it avoids the swings inherent in pH-controlled units. I do have a pH probe in this unit--though for emergencies rather than iterative control.
So far, so good. Will have to dial this one in all over again, but that shouldn't be a problem. This CaRx should easily handle my current system, as well as any future enlargements.
~~~~~~~~~~~~
The photos in this article are all courtesy of @ca1ore ©2019, All Rights Reserved.
~~~~~~~~~~~~
We encourage all our readers to join the Reef2Reef forum. It’s easy to register, free, and reefkeeping is much easier and more fun in a community of fellow aquarists. We pride ourselves on a warm and family-friendly forum where everyone is welcome. You will also find lots of contests and giveaways with our sponsors.
~~~~~~~~~~~~
Author Profile: Simon Ellis or ca1ore on the forum.
Simon has over 20 years of experience with saltwater aquariums. He has experienced first-hand the changes in technology through the years, and is happy to share his vast knowledge with us here. Simon will be featured in a Profile of a Reef Aquarist coming up soon.
~~~~~~~~~~~~
