# External reactor - pump recommendation



## Gramazing (Mar 6, 2010)

My CO2 has been running for a few days but my method of diffusion isn't so hot. I attached a limewood airstone to the output and ran the line down alongside the inlet pipe of my filter with the stone under my inlet. I have a sponge over my inlet to keep the cherry shrimp out, so I thought it would suck up the bubbles, but it's not working. There were lots of little bubbles but they mostly floated to the top because the air stone stuck out from underneath the intake.

Then I took off the airstone and blocked the end of the line, and punched a bunch of tiny holes in the line with an exacto blade. When I hooked it up to an airline it worked ok. This I thought would make it shorter so it would be completely under the inlet to my filter. However all that's happening now is the bubbles are accumulating under the sponge, congealing into one big bubble every minute or so and floating up to the surface.

So I am going to put a separate reactor under the tank. I have this thing I bought on Ebay, but it is not designed to go outside the tank, but I think I can seal it. See below:










I want to run this with an extra pump because I am concerned that if I put it inline with my canister filter I will cut the flow back too much. Also I am thinking about getting an external heater so that would be one more thing to reduce the pressure.

Does anyone have a recommendation for a good pump? One that will run outside - I want to keep stuff out of the tank. I don't know how much gph I need but my tank is higher than usual, so it needs to be over 6 feet of head. Thanks.


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## Z400 (Mar 24, 2010)

Throw that ebay item in the trash and build your own. 

Use PVC SCH40 pipe with SCH40 fittings. 

use an internal maxi-jet power head to feed it from the aquarium.


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## Gramazing (Mar 6, 2010)

I don't want a pump in my aquarium. If I wanted more crap in my aquarium I'd just hook up a power head to that thing and suction cup it to the side of my tank.


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## Seattle_Aquarist (Mar 7, 2008)

Hi Gramazing,

I have a 75 gallon project tank and I am looking at doing a DIY Cerges reactor and using a Danner Mag Drive pump (does not have to be submerged) (probably a Mag Drive 7) to drive it. I will probably also have a Hydor In-Line Heater in the closed loop system as well. That way the reactor and heater will not effect the performance of my filter and I get the extra circulation.


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## Gramazing (Mar 6, 2010)

I saw your similar response to another thread. That looks like the right pump for me, but a #7 will give you 475 GPH at 4 feet of head. Isn't that a lot? I'm not sure I want that much, I have plenty of flow in my tank right now: my substrate is always flat as a pancake. If I heap it up towards the back it flattens out within a few days. Having said that I don't want to lessen it either. I would probably get a #3 or a #5. Funny how they are quite similar.


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## Gramazing (Mar 6, 2010)

They're a little more expensive that I was hoping for.

How about these?

http://www.marinedepot.com/ps_ViewI...3111&child=TA3148&tab=1&size=1700 UL (642 gph)


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## Seattle_Aquarist (Mar 7, 2008)

Hi Gramazing,

That is a powerhead; I believe it needs to be submerged.


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## Gramazing (Mar 6, 2010)

Argh, that's why it was cheaper!


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## miles (Apr 26, 2006)

gram, 

i would do the following:

first, build yourself a pvc reactor. i like rex grigg's design, cuz it sits on the floor. or you could try the cerges home water canister filter reactor*.

second, buy a maxi-jet powerhead and run it externally on a closed loop to drive your reactor. maxi jets are inexpensive, energy efficient, quiet, and extremely reliable.

third, you wouldn't really need a powerful pump because in a closed loop, vertical head means very little. try to limit the number of 90 degree bends in your plumbing.


* a poster on the other board reported that driving more than 100gph introduces co2 mist and bubbles into the tank


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## Gramazing (Mar 6, 2010)

You mean the higher flow causes the CO2 to gas out again?


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## miles (Apr 26, 2006)

Gramazing said:


> You mean the higher flow causes the CO2 to gas out again?


yes.

that's why i suggest going with a rex style reactor. i am running 230gph through it, with very little mist and just a few bubbles here and there. i think there would be less mist/bubbles had i gone with a 15" pipe as rex suggests instead of the 12" i used. in addition, i have my co2 injecting about 3/4 the way down the reactor, instead of at the top, as per rex's, that is also contributing to the mist/bubbles.

so, go with rex's design, use a minimum of 15" pipe, and inject co2 at the top of the reactor if you don't want bubbles or mist pumped back to your tank.


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## Yo-han (Oct 15, 2010)

I'm using a quite similar external reactor (aqua medic 1000) and always used it inline after my external filter. My setup is inflow->external filter->external heater->external reactor->UV-unit->outflow. my external filter is normally 300 gph but it still pumps over 250gph. So it won't reduce the flow much and I only have a glass inflow and outflow visible in my tank. Love it!

Regards


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## Gramazing (Mar 6, 2010)

What brand is your filter?


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## Yo-han (Oct 15, 2010)

Gramazing said:


> What brand is your filter?


I've a Jebao 304. It's a Eheim-copy, but 5 times cheaper and I've never had problems with it.


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## Gramazing (Mar 6, 2010)

Yo-han said:


> I've a Jebao 304. It's a Eheim-copy, but 5 times cheaper and I've never had problems with it.


I have a Sunsun. I am sure the flow is less when it is loaded with media than when it is empty, although I have to admit I have never tested it. I am thinking it will probably be slower still if I put a reactor and exterior heater inline too.


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## Yo-han (Oct 15, 2010)

Gramazing said:


> I have a Sunsun. I am sure the flow is less when it is loaded with media than when it is empty, although I have to admit I have never tested it. I am thinking it will probably be slower still if I put a reactor and exterior heater inline too.


I assumed that as well, but I just filled a large bucket with 6G of water and timed with a stopwatch to see how long it took till the bucket was empty. The filter was rated 320gph and totally empty it even reached 330gph. with baskets and filter media it came at 315 gph and with heater, co2 reactor and uv unit a measured still more then 300 gph. So I think it does not really give extra stress to the motor of the filter and flowrate is still acceptable. Just test it!

Regards


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