# DIY inline heater/reactor...current ideas possibly overthought?



## zavikan (Jan 5, 2009)

I've done some searching for the DIY reactors, and inline heaters.

The Rex style reactor apparently doesn't use any media inside the canister.

Can we simply combine these two ideas, and make it a reactor heater?

The barb I photoshopped in could be moved up or down the tube as appropriate.









Thoughts?

I would be running this on the inlet to a 2217 eheim filter, for a 38 gallon tank w/ pressurized co2.

James


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## epicfish (Sep 11, 2006)

I see no problem with this except for the fact that you could very well get a small pocket of CO2 building up at the very top, next to the cord grip.


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## zavikan (Jan 5, 2009)

I thought of that too. But then I thought...does that matter?

Piping would be 2"

Where on this set up would I want to place the barb for the co2?

The height of my ENTIRE unit (top of heater to bottom of PVC) cant be longer then 18"

Is this long enough?


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## zavikan (Jan 5, 2009)

I will actually be using a visi-therm 200w heater. (already own one..)

The heyco part will be the same. The visi-therm heater is fully encased in the glass tube, and only has the knob stickout out of the top, so I can make it more of a flush mount, instead of having that extra height lost in the out of water section of the heater (the section of heater in the picture above, with all the writing on it). This will add precious height to the tube. This restriction is caused by the height of my cabinet (overbuilt buffet).

James


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## Hoppy (Dec 24, 2005)

I don't know how difficult it is to prime an Eheim filter, but my Rena Filstar XP3 will not prime unless I vent the top of the reactor. I have a small vent valve there, which I leave open until water flows out of it as the filter primes. When I don't do that priming is never complete. If you were to install the heater from the bottom that wouldn't be a problem - there would then be room for venting at the top.


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## redman88 (Dec 12, 2008)

you could use the heater opening as your vent.


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## wkndracer (Mar 14, 2009)

Put it all on the OUTLET of your filter not the inlet. IMO


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## brohawk (May 19, 2008)

Hoppy said:


> I don't know how difficult it is to prime an Eheim filter, but my Rena Filstar XP3 will not prime unless I vent the top of the reactor. I have a small vent valve there, which I leave open until water flows out of it as the filter primes. When I don't do that priming is never complete. If you were to install the heater from the bottom that wouldn't be a problem - there would then be room for venting at the top.


I've used an ADA knock off glass check valve on the CO2 line specifically for that reason. Turning it upside down (disconnected from the regulator of course) allows air to be blown out of the reactor so it fills and allows a prime to happen.


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## brohawk (May 19, 2008)

What's the diameter of the reactor? From my experience w/ a 2215 and 1 1/2" reactor, at about 5 bps, I can get 4"or 5"+ of air trapped at the top by the end of the night. A 2217 can handle that diameter better and probably avoid a sizeable air pocket, but if you're going 2", maybe not. You might want to rethink having the heater at the top rather than the bottom if so.

I've never had an air pocket crack the glass, but most heaters' thermostats are located near the top, which can affect your tank's temp consistency. Also, if you run it upside down, you can take the top elbow off, run it straight out, and not lose as much of your canister's flow.

And don't bother w/ the barb IMO. Just more chances for a leak. Drill a smaller diameter hole and pull the tubing through like most others here do.

EDIT: just reread that you'll be going 2". You should be fine w/ 18". I'd still recommend running it w/ the heater upside down, just strapping it to the side of your stand, and removing the (now) input elbow. One less 45 deg angle will up your flow, something you'd especially want considering your reactor can't be too long. Less noise/lack of a waterfall effect at the end of the night, and better dissolution/smaller bubbles entering your tank.

To answer your other question, you want the CO2 entering near the top of the reactor where the water is rushing in.


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## Sven (Dec 3, 2002)

what about just adding a venturi loop to the reactor and eliminating the air pocket all togeather?


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## Hoppy (Dec 24, 2005)

My experience has been that the water flow down through the reactor is not nearly strong enough to sweep CO2 bubbles out the bottom. The bubbles quickly float towards the top. If the CO2 inlet is lower there is a better chance of the bubbles becoming trapped in a big roiling mass of bubbles in the middle of the reactor. That happens in mine now, and it does make a loud noise, gurgling like water is pouring out somewhere, but it isn't. I suspect this occurs primarily with high bubble rates.


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## zavikan (Jan 5, 2009)

Seeing as this will be void of media, why not place this on the inlet to the eheim? flow into the tank would then not be restricted. I need all the flow I can get, and would rather not add a powerhead in the tank (counterproductive to me pulling things OUT of the tank)

I suppose I could mount the whole thing upside down (flipping the flow sides). That would eliminate a co2 pocket from messing with the thermostat.

I just have a mental problem with mounting the heater upside down. I suppose it doesnt really matter...I would then have to suspend it from the bottom though.. = more work.

So are you saying the co2 inlet should be lower on the tube? near the bottom?

Whats better 1.5" 2" 2.5" 3".......


This problem with priming the pump... is that presuming this is on the intake of the pump? or the exhaust side?


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## zavikan (Jan 5, 2009)

I just looked up this loop idea at http://www.barrreport.com/articles/3444-dual-venturi-diy-external-co2-reactor.html (never saw that before)

This seems like its designed for a far larger system then I am creating.

Im just not going to be pushing the kind of bubble rate/flow rate for this to matter is there? I can see that putting the whole thing upsidedown solves quite a few problems.

I am still partial to mounting the thing on the intake to the eheim instead of the exhaust. whats the pros and cons of each, for this application? Does the fact there is no media in the tube make the flow restriction a non-issue?

(just ordered my free sample part to hold the heater)


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## brohawk (May 19, 2008)

Don't bother putting this on the intake side. From experience, my flow went down even further--plus HALF of my reactor was full of air by the end of the night. I've also read posts on the net stating you can burn out the motor, as they're designed for pumping/pushing, not sucking.

You can very easily buy a couple screws and one or two of those metal strips w/ holes along them, whatever they're called for hanging/strapping ventilation pipes, etc, and place one just below the top elbow (or coupling/bushing if you decide to remove the elbow) and screw it to the inside of the stand.


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## Hoppy (Dec 24, 2005)

External reactors are almost always on the output side of the filter. If nothing else that keeps the reactor a lot cleaner, instead of having it drop much of the dirt inside the reactor. When a stream of water slows abruptly it usually drops what ever is suspended in it, and that would be the dirt being carried to the filter.

The head loss is the same no matter which side of the filter you put it on, so there is nothing to be gained, as far as flow rate is concerned, by mounting it in the inlet line.

The priming issue I have is with my reactor on the outlet side.

I hadn't thought of the problem involved with a big gas bubble at the top of the reactor, with the heater located there. That, by itself, should be convincing proof that the heater must be at the bottom. You sure don't want that heater to slowly be out of the water, getting hotter and hotter, until the cooler water shatters the glass. I'm not sure even a stainless steel or titanium heater would survive being in a gas bubble.


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## zavikan (Jan 5, 2009)

Hmm.. I had heard that if you put it on the input side of the canister, you didnt lose the flow...

Considering the inlet to the filter is 5/8 and the outlet is 1/2, I would think that having this PVC on the larger diameter side, would keep the flow up. Is my logic faulty (I can handle it if im wrong. :icon_smil)

Am I wrong?


If I am, this is my 2nd drawing. I have respaced the the co2 input, and flipped the T to the direction I would use under the tank.

The top can either have the elbow-capped-1/2 straight barb, or it can be capped- 1/2 90degree barb. which way is better? It has to go horizontal b/c of space.

I am still studying the venturi system (I dont get it)...the learning curve is high enough that I need some time lol. Would this be a useful application for me? Obviously I cant have the heater elements out of water...

James


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## Hoppy (Dec 24, 2005)

I would move the CO2 inlet up onto the straight section of pipe, maybe an inch or two up on that pipe. I think this configuration will give the minimum head loss.

This type of Tee would give a lower head loss too:








You have room at the bottom to put a 45 degree pipe to barb fitting to get the rest of the bend made. There is less head loss with a longer bend than a short bend. 

The flow coming into the filter and the flow going out of the filter both will experience head losses when there is any form of restriction in the lines. And, a reactor with a heater is definitely a restriction. On the inlet side you can get cavitation from restrictions, where on the outlet side the flow rate just decreases.


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## zavikan (Jan 5, 2009)

Hoppy:

Absolutely, the 45 Tee makes alot more sense. I will incorporate this, thank you.

By that standard, the top should remain a PVC elbow to straight barb, vs the straight PVC to barbed Elbow. The PVC elbow allows for less head loss (yes?)

The system will run 24/7
As far as preventing a gas bubble at the top, is this really a concern? Would the aforementioned venturi system work?

If the venturi system would work, could some one easily explain it? I still am having trouble visualizing it.

small tube next to the top inlet goes to...where?


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## Hoppy (Dec 24, 2005)

I would leave the top elbow as it is. It is internally smooth and a fairly large radius too. There are larger radius elbows, but I don't think they are made in PVC. The gas bubble at the top isn't a problem, once you remove the heater from the top, other than that it does make it a noisier device.

The venturi system sucks out CO2 from the bubble at the top, recycles it through a pump, preferably, and sends it back to the reactor as much smaller bubbles. I haven't tried the venturi modification, so I have no idea how well it works in practice.


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## zavikan (Jan 5, 2009)

ook...

So I think the main idea is pretty well developed now..

Question regarding flow...

Is it possible to add a second pump to the system? like a modified power head:







( I have one of these laying around) it has an attachment on it to suck air in. co2 would be just as fine.


Would the two pumps battle each other? would my little penguin actually slow things down?


Light Green - venturi tube
dark gray - powerhead
light gray - pvc
dark green - canister
pink - co2 Canister


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## zavikan (Jan 5, 2009)

the pump could also go back to the inlet of the eheim.


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## zavikan (Jan 5, 2009)

god I post to much....


I wish I could just sit down and chat with some of you people!!!!!!!!!! then when I forget something, I could just say it, and not have a million posts..


my penguin is actually a 1140 apparently.


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## zavikan (Jan 5, 2009)

ya know, I think this maybe totally unapplicable to me. Its only a 38 gallon tank. 

Just the PVC should be all I need. This reactor should be big enough to 100% dissolve the ammount of co2 needed for this size tank right?


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## malaybiswas (Nov 2, 2008)

The main possible problem I see with diy inline heater is maintaining the contact period of the water to the heater surface so that the water temperature is maintained to the desired limit. I don't think just setting the dial to 75 degrees and then flowing water against it would maintain the water temperature at 75 degrees. Either the heat generated by the thermometer needs to be higher than 75 degrees or the water needs to be practically stagnant for some period of time before it reaches the temp and then flow away (guess that option does not work).

That's why inline heater wattage is higher than normal heaters (e.g. if you need about 100w heater for 40g tank, you'll need 200w of hydor eth inline heater for the same tank). the higher energy released heats the water faster so that the water can heat up to the preset limit while it is flowing thru the heater (and a lot of the heat produced is actually lost). Also, the flow path within the heater is not exactly straight to maintain higher contact period.


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## brohawk (May 19, 2008)

malaybiswas said:


> The main possible problem I see with diy inline heater is maintaining the contact period of the water to the heater surface so that the water temperature is maintained to the desired limit. I don't think just setting the dial to 75 degrees and then flowing water against it would maintain the water temperature at 75 degrees. Either the heat generated by the thermometer needs to be higher than 75 degrees or the water needs to be practically stagnant for some period of time before it reaches the temp and then flow away (guess that option does not work).
> 
> That's why inline heater wattage is higher than normal heaters (e.g. if you need about 100w heater for 40g tank, you'll need 200w of hydor eth inline heater for the same tank). the higher energy released heats the water faster so that the water can heat up to the preset limit while it is flowing thru the heater (and a lot of the heat produced is actually lost). Also, the flow path within the heater is not exactly straight to maintain higher contact period.


Ya know, I've got to disagree w/ you on this. Normal inline heaters only minimally interfere w/ flow, thus they must be higher wattage, whereas a normal in tank heater placed in a reactor, where the flow is slower and amount of water is smaller, actually becomes more efficient. I've found that I have to lower the thermostat to keep my tank's temp the same after installing the same heater inline.


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## brohawk (May 19, 2008)

I wouldn't bother w/ the venturi at this point. If you set it up and find it to be producing a huge gas bubble later in the day, you can always go back and add the extra tubing and attach to a powerhead or even plumb it back into the input or output of the eheim.


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## Hoppy (Dec 24, 2005)

I would forget about the venturi modification until you see that you need it. I have a 45 gallon tank, with just the external reactor, and I can easily kill fish with the CO2. Simple is usually best. I think the worst thing that will happen is that the heater will cause more head loss in the reactor, cutting the flow from the filter more than you prefer. If so, the easy fix is a Koralia or equivalent powerhead in the tank, augmenting the water circulation.


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## sewingalot (Oct 12, 2008)

Helpful link: http://www.pricenetwork.ca/deal/DIY_Co2_Reactor_and_In_line_Heater-166935.html


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## Hoppy (Dec 24, 2005)

sewingalot said:


> Helpful link: http://www.pricenetwork.ca/deal/DIY_Co2_Reactor_and_In_line_Heater-166935.html


Don't use the 2" wye fitting to inject CO2, as shown in that link. I tried something along those lines and it didn't work at all well. What happens is the CO2 forms bigger bubbles in the wye, which immediately collect at the top of the reactor, instead of being bounced around in the middle of the reactor. When I switched to a simple hole for the CO2 tube near the bottom of the reactor the efficiency of the reactor improved greatly, and the CO2 tends to stay in the middle as a mass of small bubbles bouncing around in the flow.


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## airborne_r6 (May 2, 2008)

brohawk said:


> Ya know, I've got to disagree w/ you on this. Normal inline heaters only minimally interfere w/ flow, thus they must be higher wattage, whereas a normal in tank heater placed in a reactor, where the flow is slower and amount of water is smaller, actually becomes more efficient. I've found that I have to lower the thermostat to keep my tank's temp the same after installing the same heater inline.


I have to agree with this. You dont have to heat the water all the way to the desired temperature before expelling it from the reactor it only has to be heated a small amount because you are heating all of the tank water a small amount and then a another small amount and then another small amount until it reaches the desired temperature. The ablility of water to retain its heat and the poor ability of air to pull it away keeps that small temperature gain from being lost before it is heated again.


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## airborne_r6 (May 2, 2008)

Do you already have this filter running on the tank and are just looking to add the reactor or is this a new setup.


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## plantbrain (Dec 15, 2003)

Here's a little something to gnaw on:

If you can add a heater in line, what about a small powerhead in a 2-3" PVC chamber? You need to have the seal for the electric cord, but they make grommets for this. For smaller systems, this might be an idea.

For larger systems,a mag drive 2 with in line needle wheel, then "fur" up the impeller more with some scotch brite shreded material(use scissors to dice it up, or sand etc and glue).

This loop would drive a pretty large tank using the mag drive.

Regards, 
Tom Barr


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## zavikan (Jan 5, 2009)

*lalalala*

I'm still waiting on the heyco part. its been shipped though.
tank has been running a few weeks. canister has been running around a month and a half. I did an emersed 3 week cycle (worked like a charm) when I tore down my old tank for this one. the water never had a hiccup.

I'm not exactly sure what your suggesting Tom...why would I plum a power head inside the tubing, instead of just getting the fittings for it?


For now, I just wait until the heyco part comes in the mail...

My main concern is loss of flow. adding a powerhead in my tank would be TOTALLY counterproductive to doing all this.

do any of those output caps to 'improve flow' actually work?

James


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## airborne_r6 (May 2, 2008)

Actually Tom brings up a good point. Instead of a powerhead why not just plumb in a pump and turn the canister off. You will still have the canister plumbed inline for the filtration but rather than trying to augment the flow of the canister just get a pump with the flow that you need.


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## zavikan (Jan 5, 2009)

seeing as I paid $160 for the canister a little over a month ago, leaving it unplugged does not appeal to me. Perhaps illogically though hah.

I have heard on another site, that the canister is designed for flow thru even when the pumps are off. This in mind, augmenting the flow should be no problem at all.

As it stands, I have desided my first move will be getting my PVC up and running by just putting it on the return side. From there, the questions are

enough co2 dissolved?
Quiet enough?
does the heater work?
no co2 bubble forming?
enough FLOW?

I am expecting everything to be ok, except for possibly flow.

If flow is no good, I am going to try and put my penguin 1140 right AFTER the reactor, to push water up to the tank harder. I have no idea what this will do honestly.

James(waiting for my hetco part)


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## biggdadyapisto (May 30, 2009)

updates?


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## zavikan (Jan 5, 2009)

hetco came through with their part. I have two neat little pieces. I am currently on vacation far away from home until next monday. At some point next week, I will put this reactor/heater into motion. I am hoping my tank isn't hellish after 9 days of 0 ferts. lights on a 5 hr photoperiod. We'll see.


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## Rusty (May 7, 2009)

Hey mate, how will you be holding the heater in the pvc as the pressure could push it out, could it not if you are just using o-rings or something. Also what if you forgot about the barb and used another independent reactor. 

On another note, i'm currently getting ready to set up a 5x2x2 and will be either using an 1800 or 2200 lph (around 450 - 550 gal) cannister. Will this setup work for me? A thicker pipe of course and will be using a jager 300W. Sorry if this steals your thunder Zavikan.

Cheers,
Rusty


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## zavikan (Jan 5, 2009)

Well, so ya know. It went bust. I installed the unit, and was happy until I watched my temp rise from 74 to 80. I pulled the heater to find it shattered. A new one costs around $20 to put in this unit. the ABS assembly itself cost around $25.. A brand new hydor 200w inline on ebay is going for $44 shipping included.

I just purchased it.

I hope to reuse parts of this abs crap to make a standard co2 reactor. For now, I'm limping the tank on a 100w heater thats older then I am, and using the good old glass diffuser.

Waiting for my nice quality hydor to come. to hell with DIY.


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## airborne_r6 (May 2, 2008)

zavikan said:


> Waiting for my nice quality hydor to come. to hell with DIY.


:icon_lol: Thats half the fun of DIY, getting to spend twice the money and twice the time to hopefully have a product, that is as good as what you can just buy. 

But seriously, sorry about how that worked out, you should be happy with the Hydor.


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## Hoppy (Dec 24, 2005)

Not all of our DIY attempts are successful. My average can't be much better than 50%, if that. But, I agree with airborne r6, I really enjoy the effort enough to justify the expense, even when it doesn't work. And, on the rare occasions when it works just as I hoped, the thrill pays for all of the disappointments.


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## Justshoe (Aug 17, 2008)

I'm also looking to do this to my tank as well. Anyone thought of using one threaded fitting on the end so that you can disassemble the unit? 
Also had the thought of using a small wooden airstone inside to help diffuse the co2 better.

And have we decided that drilling a hole and passing the line through the pvc is the best idea? also with some silicone on it i suspect.


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## Hoppy (Dec 24, 2005)

Justshoe said:


> I'm also looking to do this to my tank as well. Anyone thought of using one threaded fitting on the end so that you can disassemble the unit?
> Also had the thought of using a small wooden airstone inside to help diffuse the co2 better.
> 
> And have we decided that drilling a hole and passing the line through the pvc is the best idea? also with some silicone on it i suspect.


The first CO2 reactor I made, several years ago, had an airstone inside, to give me smaller CO2 bubbles. After a couple of years the airstone was a small pile of sand! That taught me that if you do include such a feature, be sure to make it so it is easy to get access to the airstone for cleaning and replacement. If I were to try something like that again I think I would try to use a small hypodermic needle to get the small bubbles. That, at least wouldn't require regular cleaning. It is also possible to heat and draw out a piece of plastic tube into a fine "needle" end.


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## Justshoe (Aug 17, 2008)

Thats why i was thinking of making one end able to be disassembled so you could easily replace and also double check there is nothing happening to the heater....

Also i know most diy inline reactors are using bioballs to help diffuse the bubbles better. Do you think you would still want this with the heater also being in there or just have the heater and possibly an airstone


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## Hoppy (Dec 24, 2005)

I wouldn't use the bioballs in any case. I agree with Rex that they do nothing except add more head loss. When my reactor works well the normal sized bubbles just get trapped in a swirling mess in the middle of the tube. They don't shoot to the top at all, nor do they get swept out the bottom.

I doubt that a heater stuck into a reactor is destined for a long life, as this one demonstrated. Since the CO2 bubbles form a mass of swirling bubbles in the middle, that interferes with heat transfer from the heater tube, allowing the heater a chance to overheat. In my reactor, the mass of bubbles slowly grows all day, and by the time the CO2 shuts off, most of the tube is full of bubbles, not water. I'm guessing that is what caused Zavikan's heater failure.


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## Justshoe (Aug 17, 2008)

I cant imagine with proper flow through the reactor you would get a large amount of trapped bubbles. Heres my plan for the time being


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## Hoppy (Dec 24, 2005)

Justshoe said:


> I cant imagine with proper flow through the reactor you would get a large amount of trapped bubbles. Heres my plan for the time being


Your sketch shows the water going from bottom to top in the reactor. That won't work well, since the water will just sweep the CO2 bubbles right out of the reactor to the tank. If you reverse the flow, it does look like it stands a good chance of working. The important thing is that the flowing water is the coolant for the heater, so it has to make good contact with the heater, and has to be sufficient flow to pick up enough heat from the heater to keep it "cool".

The trapped bubbles of CO2 are what makes the reactor efficient - the bubbles are held in suspension long enough to dissolve into the water. But, the real problem is that we increase the bubble rate until we get the amount of CO2 we want in the tank water, but don't make sure this isn't overwhelming the reactor to do it. I know I rarely look at the reactor to see what's happening in there. (It is dark down there under my tank, and no fun getting down on my hands and knees with a flashlight to see what's up.)


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## eyebeatbadgers (Aug 6, 2007)

I wish I had seen this thread a month ago! I've been here and done this!

Here's the link to what I built a good while ago. It works very well, no need for bioballs, airstones, etc. 

I don't run my Co2 into this anymore, as I really prefer misting to dissolving the Co2, but I do still use this to hide my heater outside of the tank. If you want to see the Co2 setup I use now, you can click on the 29 gallon link in my signature. Basically, I have a canister filter, fed into the PVC heater hider, then fed into a needle wheel pump (easier than bothering with roughing up the blades, for the same price you can buy a real needle wheel) I feed the Co2 into the tubing just before the pump, and the water re-enters the tank. A picture is worth a 1000 words


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