# Reactor Woes



## Muirner (Jan 9, 2007)

Ok, so I thought that my reactor design was going to work out pretty good, but, after having it up and running a week, I think I need to revamp. Currently my reactor looks like 









It's about 2' long end to end, and filled with biorings. The problem is, even with the flow gated down from my XP3, i'm still getting bubbles pushing out the spray bar. True they are little but it seems a decent #. Also it makes an annoying noise when the bubble goes past the gated down filter. Dissolvtion isnt 100%, and my plants dont peral till noonish.

Now the problem is this. I cannot make a reactor that has a 90* on each end. The height of the filter (XP3) means the water goes in the 90*, the reactor is zip tied to the broad iron stand, and the tubing is hooked to the straight part and goes right up about 1-2' to the connector to the spray bar.

My thoughts on a remedy: Take the 90* and extend that out another 2' or so, fill with biorings or something. But is is this going to cause major problems? Or can someone help with some advice? I'm driving myself nuts.

OH ya, i have a drop checker the KH standard should be in tomorow, (I HOPE) and i'll be hooking that up.


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## jeff5614 (Feb 15, 2006)

I think moving your CO2 input to the top and having the water come in at the top and exit the bottom would take care of it. The bubbles are trying to move upward against the flow of water so the CO2 has much more time to dissolve.


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## Muirner (Jan 9, 2007)

So move the brass hose barb to the top? and then flip the reactor so the intake is on the top and discharge is out the bottom? Or would you flip it end to end? 

I'm just confused on the "The bubbles are trying to move upward against the flow of water so the CO2 has much more time to dissolve." I just dont get how this would happen. If i move the intake to the top, then if i inject there, and leave it how it currently is then it'd just bubble right out the top.


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## k-maub (Feb 10, 2007)

If I understand you correctly, you have the connections upside down to begin with. The water needs to be travelling with gravity, i.e. from the top to the bottom of the reactor. In such a configuration, you can put the CO2 injection at the top, and the bubbles won't be able to escape since the flow is pushing down against them. Right now, your bubbles natural tendency is to move with the direction of flow, so that is exactly what they are doing, making it easy for them to escape before they dissolve.


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## AaronT (Apr 26, 2004)

k-maub said:


> If I understand you correctly, you have the connections upside down to begin with. The water needs to be travelling with gravity, i.e. from the top to the bottom of the reactor. In such a configuration, you can put the CO2 injection at the top, and the bubbles won't be able to escape since the flow is pushing down against them. Right now, your bubbles natural tendency is to move with the direction of flow, so that is exactly what they are doing, making it easy for them to escape before they dissolve.


I think he ^ hit it on the head. It sounds like you have the reactor on the outlet line. It should be mounted on the inlet line so the bubbles are forced to travel upwards against the flow of the downward traveling water.

Did you fill the reactor the entire way with bioballs? You only need a few in there to move up and down and churn the bubbles up a little bit.

Also, you say the plants only begin to pearl at noon. That's relative to when the lights turn on though. What time do they turn on in the morning?


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## Muirner (Jan 9, 2007)

OHHHHHHH so this should be on the Input side of my cannister? I have it hooked up to the return side! The 90 is where the hose from teh cannister goes. So if i leave it as it is now, And hook it to the intake side of my filter. The 90 will be at the bottom, closest to the hose connecting to go to the cannister. is that a good place to inject? Or do i want it to be elsewhere? 

Yes i put like 15 biorings in the reactor. And the lights come on at 9am.


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## jeff5614 (Feb 15, 2006)

Sorry I wasn't too clear. Let me try again. Mine is on the output side with the water flowing into the top of the reactor and out the bottom with the CO2 input at the top of the reactor. The bubbles of course try to float upward against the direction of the water flow. That coupled with the length of the reactor gives the CO2 time to dissolve before any bubbles would be pushed out into the tank. At least it works for me anyway, lol.


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## Muirner (Jan 9, 2007)

do you have a picture of your setup by chance? I'm just not sure how i'd rig that up.


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## jeff5614 (Feb 15, 2006)

Have a look at Vicpinto's setup in this thread. The CO2 input is at the top of the reactor.

http://www.aquaticplantcentral.com/forumapc/aquarium-equipment/39603-co2-external-reactor.html


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## flandjm (Dec 28, 2006)

Just to add my two cents to the confusion:









http://www.rexgrigg.com/diy-reactor.htm

The above pic is from Rex Grigg's Website.

I had a real bugger of a time figuring it out also. It seemed contrary to common sense... until I really thought about it. The left side goes down, and the right side goes up... as straight as you can get it. It bubbles lots the wrong way, it works like a miracle the right way... and mine is not 100% straight, and doesn't have any bioballs or baffles.


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## Muirner (Jan 9, 2007)

flandjm - i used that model to try to attempt to do mine. Now did you hook yours up on the discharge or the intake? I'll see what i can do about reversing this.


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## AaronT (Apr 26, 2004)

Yes, hook it up on the intake side. Have the inlet for the CO2 on the bottom. The bubbles inside the reactor will rise up against the downflowing water and get churned up and dissolved 100%. Most people set up their reactors this way. Try it and I think you'll be pleasantly suprised.

On a side note, pearling 3 hours after lights on it pretty good. I wouldn't worry about trying to get it to happen any earlier.


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## Muirner (Jan 9, 2007)

Ok, sounds good. It looks like my KH solution should be here by the end of this week so i can get that hooked up. Also, i'll try to find a way to rig this up, so i dont get a bunch of air in my xp3, currently for some reason even with my reactor set up on the discharge side, every few days if i look ihave built up about 1/2" of "air space" which i can confirm by moving the cannister forwards and backwards, this will show water movement into the areas that are previously filled by air.

I'll have to try to rig something up tomorow between end of the semester push homework (that i had all semester to do) and work.


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## flandjm (Dec 28, 2006)

Mine is the opposite. I have mine on the output side of my Eheim 2217, in the orientation I previously mentioned. I seem to remember reading somewhere that it is better to not put things on the intake of your cannister filters because it is harder on the pump, and has the potential to airlock the cannister. Personally I just rather like the thought of "clean" water flowing through it not "dirty."

My other lesson in this was to make sure to have and close the double tap connectors between the reactor and the filter during water changes, and to shut off the CO2. I was really swearing one night because during a particularly long maintenence, the reactor filled with CO2 I hadn't shut off, and then airlocked the filter. I had a real bugger of a time getting prime again. Eventually I ended up hooking my python to the end of the output of my filter... I got rather wet and angry with the whole ordeal.


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## Muirner (Jan 9, 2007)

Ok, but the thing with hooking it to the output is, the bubbles are going to flow with the water, unless, i set it up to flow in reverse, I'm not sure how i'll set this up but i gotta think about it a lot more.


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## vicpinto (Mar 27, 2007)

I think there's some confusion with regards to inputs and outputs here. For all intents and purposes it doesn't really matter if you have the reactor before or after the filter so let's forget about the input or output side of the filter.

What does matter is that the reactor is mounted the right way. It needs to be vertical with the CO2 AND water inlet on the top. I know it seems counter intuitive but the flow of the water through the reactor will force the CO2 bubbles down through the bioballs. The turbulence created by the bioballs should dissolved the CO2 completly. 

The only time the reactor fills up with CO2 is if I open up the needle valve so that I cannot count how fast the bubbles are coming out or when I perform filter maintenance and forget to shut off the CO2 flow. In both cases the CO2 has displaced the water in the reactor. To correct this I detached the reactor and simply flip it upside down for a couple of seconds (burp the reactor so to speak). 

SUGGESTIONS:

1) Leave yourself some slack in the tubing to allow you flip the reactor to burp it.
2) Swap out the center section with clear PVC pipping so you can see what's going on inside.


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## Muirner (Jan 9, 2007)

I wish i coul find clear PVC, heck even finding someone who is good with PVC in town is hard HAHA. Anyways, i think i may have thought something up. What if, i take this reactor and put the orient it so it looks like a tabacco pipe you know, long end to the left and then the 90 at the end (here crude ASCII drawing) --===========||_ the small line at the end of the || is the co2 imput. I'll hook the reactor to the intake of the tank, this will pull water through the length of the reactor, and the bubbles will want to float against the grain. Does that sound right?


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## ponyrandy (Jan 13, 2007)

Just trying to clarify the inlet/outlet placement of the reactor:

If you put it on the output side of the filter wouldn't you have to pump the water up to the top of the reactor (assuming the reactor inlet is a few inches higher than the filter output), then down the reactor and then back up to the tank? This seems like this would be hard on the pump.

If you place it on the input side it would just go in the suction tube line and gravity and suction would do all of the work. This would eliminate the water flow snaking around to get back up to the tank. The co2 would also be dispursed better by going through the reactor and the filter.

If the co2 went in at the bottom of the reactor wouldn't some of the co2 be pulled straight out of 
the reactor depending on the strength of the flow without the bubbles ever rising into the reactor body and dispersing around the bioballs? If the co2 were put in at the top of the reactor where the flow is the strongest then the gas would have to be pulled down into the bioballs for dispersement?

I have not built mine yet so I have no experience but I have been following this with interest before I get started.


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## ponyrandy (Jan 13, 2007)

Muirner, from what I have been reading I believe the consensus is that if the reactor is not vertical, the gas would just rise to the top of the reactor and not get dispersed.


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## Muirner (Jan 9, 2007)

pony - i'm thinking the same thing about head pressure. These XP3's are nice, but i'm not looking to burn it out, by having to wind hose all over kingdom come because i f-ed up this design would be hard. BUT, putting it on the intake side i could get air in my xp3, I have to call rena because i have a leak in the return plastic piece, and also my canister has about 1/4" of air and i just burped it a few days ago...


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## ponyrandy (Jan 13, 2007)

Yeah I agree about the gas accumulation in the filter. My thoughts were that it would be well dispersed into the water coming out of the reactor therefore it wouldn't accumulate as much in the filter. The more I read and discuss this the more I think that the best way might to have an external pump whose sole purpose is to pump the water through the reactor. It could either come on and off with the co2 solenoid or it could just run 24 hours for circulation.


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## Muirner (Jan 9, 2007)

But that's what my xp3 is, I have no media in it, and it's sole purpose is to move water HAHA. Hm what cha gonna do, i'm gonna hook up my drop checker i just got the fluid, and i'm gonna check my co2 levels.


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## Squawkbert (Jan 3, 2007)

My 1st thought - water is pushing bubbles out faster than they float up. Answer: flip ends.


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## Muirner (Jan 9, 2007)

but then if i flip ends, the injection will still occur at the top, if i end up having to revamp i'll then pull the brass hose barb out. 

I'm thinking of hooking it up on the intake side.

EDIT: I have it hooked up to the intake side now, on a slight angle with the higher end being the 90 end. Lower end is about 6" from my filter intake. Injecting at a little over 1bps, and i cant hear any bubbles making it into the cannister, which is a good thing if you ask me. I did a little bit when i cranked the flow rate to max, but i turned it back a lil and i'm ok. How do i make sure they are not going up the intake line though?


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## ponyrandy (Jan 13, 2007)

My theory is they can only go to the u-shaped bend at the top of the tank. Any co2 that went up there is still in the turbulence of the water coming into the intake and will eventually disperse into the water.


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## ponyrandy (Jan 13, 2007)

Also if you have a clear intake tube you should be able to visually tell if this is happening.


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## furballi (Feb 2, 2007)

Same basic design found in the Aquaclear 300/500...inverted U-tube trapping the CO2 and allowing the CO2 to mix with the incoming tank water. This is a very efficient way to diffuse CO2 into the tank.


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## Muirner (Jan 9, 2007)

But with the XP3 intake, there is a little part that is used to help prime the filter, you cannot over fill the intake tube because of the design, makes me think there is some CO2 up there (well hypothetically there could be)

EDIT, my drop checker is in, and this morning i found it to be (What appears to be) Green. It's not a bright green it's almost "clear" it'd seem I'm using the Chameilian drop checker with the included reagent. Not sure why, but it dosent look brigh gren, well at times it does. But not "bright" Then again it's right infront of some growing plants, Oh ya i used 3 dropps of the pH solution to 5ml of 4dKH solution


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## Rex Grigg (Jan 22, 2004)

What diameter is the PVC of the reactor?

I have built more reactors than most anyone that has responded to this thread. So I think I MIGHT have a bit more knowledge than most.

I really prefer to have the reactor on the outlet side. Water in the top and out the bottom. CO2 injected in the top third of the reactor. Nothing in the reactor. Nothing. Not a thing. Not sure where people get this idea they need something in the reactor that will slow down the flow and capture crud and clog up. And just the way Mr. Murphy works the day the reactor clogs will be the day you are out of town for the next 36 hours and you will come home to a disaster.

Works like a champ.

If you think you need clear PVC, and I can't imagine why one would want it for a reactor then try http://savko.com/


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## Muirner (Jan 9, 2007)

My reactor is 1" in diameter, and about 2' maybe 2.5' long


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## Rex Grigg (Jan 22, 2004)

The diameter is much too small. With an XP-3 driving it the minimum you would want is 1¼" diameter pipe. 1½" diameter would be much better.


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## Muirner (Jan 9, 2007)

Crud, idk where I can find that locally. I might be able to actually find 1 1/2... I'll have to look more into the issue. Anyone wanna buy a reactor?


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## Rex Grigg (Jan 22, 2004)

Try the BORG. It's pretty common stuff and not hard to find at any decent hardware store.


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## Muirner (Jan 9, 2007)

BORG? I think i'm looking into building a new reactor.


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## Rex Grigg (Jan 22, 2004)

BORG = Big Orange Retail Giant aka Home Depot.


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