DIY Calcium Reactor from a Canister Filter

gpodio

gpodio

Premium Member
After ordering acrylic to build my own reactor I realized that using one of my spare canister filters would save me a lot of time and effort...

A quick run to Home Depot and a couple hours later later:

ca_reactor.jpg


I played around with the positioning of the "in", "out" and the T several times. Placing them both as shown gave me the best results. Having both in and out tubes above the canister allows easy disconnection of the canister itself without spills.

Unfortunately the choice of couplings and options were limited at Home Depot so I ended up using regular threaded John Guest fittings and cut the thread away on the lathe to turn them into barbed JG fittings... If I were a little more patient I could have probably ordered everything online and put it all together with no tools.

The canister is an Eheim 2217, can't remember where I got the JG needle valve, I pulled it from my Kalkwasser setup. It's been running for 4 days now in a tub without media and seems to be very consistant and silent. I'm looking forward to filling it with media perhaps this weekend and hooking it up to the tank!

Cheers
 
awesome idea, too bad i only have a crappy fluval laying around. i can barely get that thing to hold water let alone expensive CO2. :D curious to see how this works for you.

What type of media you using? The course chunks or an aragonite sand type?

-nick
 
I hear ya Nik, I've been using canisters as CO2 reactors for many years and the Classic Eheims are certainly the best for any such task. Besides the quality of the seal, they never airlock if the tubing is correctly positioned.

I purchased 2-3mm grain sized aragonite media. I'll be using cut out discs of needlepoint graph to keep the media in place and an extra sponge block on top to stop any particles getting to the impeller or needle valve.
 
Wow... a non-powered canister from Eheim... That's gotta be a rarity! Current models of the 2213 canisters are simply a smaller version of the one I'm using here...

If you find one of those with an external pump you're very lucky! It would make a great second chamber for this setup!
 
Last edited:
Here goes... Hooked it up last night, it holds a gallon of media with some room to spare. Used the Eheim foam pad on top with some filter material wrapped around it for a snug fit. On the bottom of the media is a fine mesh from a media bag sandwiched between two discs of needlepoint graph. Also using the standard Eheim separators that go on top and bottom of the media to create a gap for even circulation.

ca_reactor2.jpg


It's currently set at a conservative 20bpm, 40ml/min. Curious to see how it performs over the next few days...
 
It's a Mag 1.5, it had the perfect nozzle size for the tubing to fit over.. It's picking up water from the return chamber and sending it back to the skimmer area.
 
Correct, the canisters' own pump is re-circulating the water through the media, while the little Mag 1.5 is feeding it water from the tank and creating the required pressure to push water out the output tube...

When I was testing it empty I also had the intake tube plumbed up to the display so that it would be gravity fed, but I was concerned about power outages so I preferred to go the normal way and use a small pump. The Mag 1.5 is a little overkill, I think I will try a smaller pump next and conserve a little power and heat...
 
Brief update... Everything is looking fine except that when testing PH of the effluent it was the same as the tank water... After a little tinkering I realized that the 12psi I had the CO2 regulator set at was insufficient to push CO2 into the canister. I constricted the Mag 1.2 a little and brought the CO2 pressure to 17psi. I can now see the bubbles running down the short green tube under the CO2 barb. So a little delay in getting some numbers from this thing, if I had a bubble counter hooked up inline I would have noticed this earlier...

Tonight will be 24 hours since CO2 is working, I'll update once I get some initial numbers.
 
I always thought that you wanted to break up the CO2 Bubbles with the pump impeller. that way the bubbles are more easily drawn into the reactor without using so much pressure. could use a small pump to make it all work and keep the canister motor unplugged. Like the concept though. I have extra eheims laying around, could put them to use.
 
I don't know... in my experience breaking up CO2 bubbles is important when contact time is limited, much like breaking up bubbles for a skimmer. But here the CO2 will be mostly trapped under the media until absorbed by the water... The little that does make it through the media gets broken up by the impeller and sent back to the bottom of the media... at least that's my logic for now :-)

At worst, I'll add a piece of rigid airline tubing running through the media so that trapped CO2 has a way to get to the impeller for a good 'mincing'...

In using these canisters as CO2 reactors in my planted tanks, I acchieve 100% absorption just sending CO2 into the intake strainer so I'm hoping it will work just as well with saltwater and in a recirculating situation...

Once I replace the Mag 1.5 with a smaller pump, pressure should not be an issue. The Mag 1.5 has a 6 foot head rating, the Eheim canister is around the same so the canister itself should be able to sustain this pressure long term...

If I do have to go to an external pump for any reason I'll recuperate the canister and build my own chamber. Kind of looses it's appeal and benefits if I have to add an external pump...
 
Tonight the effluent KH is 11 (Tank is 4.2), PH is below my test kit range... :rolleyes: I'll give it another 24 hours before making any adjustments.
 
Effluent was the same after 48 hours so it's nice and consistatant. I increased bubble and flow rate, I'll update once I get it dialed in and all.

Quick question: Within "typical" bubble and flow rates, do effluent PH and KH go hand in hand? Another words, if the effluent KH is measured to be 30dKH, can I assume the PH is somewhere close to the target level?

Reason I ask is I'm waiting for a PH meter to arrive so I can't measure PH that low right now. I imagine that any changes in bubble or flow rate effect both PH and KH of the effluent (not using a controller obviously).

Thanks
 
Update: I adjusted the reactor on Friday to give me 20dKH from the effluent @ 60ml/min flow rate. I won't bring it any higher until the new PH monitor arrives just to avoid any problems. After adjusting the tank's levels to ideal, it has held the levels for 3 days straight with just a minor drop so I'm getting close to what my tank needs.

Overall I'd say this was a great use of a spare canister!
 
It's currently running 80bpm @ 60ml/min, effluent PH is PH6.7. The tank has risen from 1.5meq to 3meq and holding steady for the last 10 days or so. The tank's PH rose to 8.2 from a 7.95. I can already see my coraline growing on the glass again, it hasn't done that in a year :D I'm very happy so far!

I was wondering if I should slow down the effluent a little and lower the PH to 6.5... that's the target value I have read. If the tank is holding 3meq though, which is perfect for me, should I really play with it at all? Are there elements in the media which don't dissolve as well as others at PH6.7? If I recall the article I read, it said the target PH is 6.2-6.5. Thoughts?
 
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