Hi,

I have recently made my own version of the inline rex reactor using materials available here in the uk. I have used 18" of 40mm pvc pipe but instead of T fittings I have used a straight fitting at the top with a removeable rubber sealed end cap, at the bottom I have used a 45 degree fitting with the same type of end cap. The hose tails are straight and securely fitted to the caps with a plastic nut which I have sealed with silicon. The reactor is installed on the inlet pipe of my eheim ecco 2234 filter.

The problem I am experiencing is that I seem to be getting alot of CO2 gas built up at the top of the reactor, this is causing alot of noise which sounds like water sloshing through the reactor. When my CO2 is turned off by the timer when my lights go out this noise goes on for several hours and well into the night. I did not sleep well last night and I think the noise did not stop till 6am. Is this normal? It seems to me that the gas is not being dissolved quick enough and this is why I'm getting build up. What can I do to stop this noise?

Alan

Below is a photo of my reactor hooked up to the filter (please excuse the all the wires).

Well, first off, did you "burp the reactor?
When you first start up, usually there is a lot of air in the reactor. If you don't have something built in to get this gas out, just turn the reactor upside down until all the air is purged from the reactor.

If you did burp it, then it sounds like you are pumping in more CO2 than can be dissolved in the length of the reactor.

Concerning the co2 line in the reactor, does it go at least 3/4's of the way down?
You could put Bio-balls or something else to impede the CO2 bubble travel to the top. However you may have more issues cleaning it out especially by having it on the inlet side (really should have it on the outlet).

HTH

Thanks for your reply.

Firstly I have added an arrow to show the water flow through the reactor.
I have "burped" the reactor by using the priming leaver on my filter, this gets rid of most of the air inside and the rest clears after about an hour when CO2 is not pumped. Unfortunatly it is impossible for me to turn the reactor upside down as the filter pipes are not long enough.
As you can see from the photo the CO2 line is about 3" from the top, maybe this is the problem but I though that this was where it was supposed to go. Thinking about it now though I guess the length of the reactor is necessary so the CO2 travels all the way up the reactor. If this is the case maybe I could just reinstall it the other way up, which is a shame because I used the 45 degree angle at the bottom so it lines up with my filter perfectly. I dont think I will be able to seal the hole that I have drilled at the top, any suggestions?
I dont really want to have to put a bio ball in it but if I have to maybe this is the answer.
I thought it had to go on the inlet side of the filter as the gas should travel up against the flow of water thus dissolving efficiently, I'm thinking that if it was on the outlet the gas would just be pushed into the tank through my spraybar and not be dissolved properly.

What is the GPH of your filter or I should say LPH in your case ?If your filter is not strong enough to break the bubbles ,then you probably need a more powerful filter for that reactor.
I also had some air trapped on top of the reactor when I first installed it ,that is normal and will go away in a couple of days,if it does not,then it could be the length , or the diameter of your reactor than is causing a problem but I suggest that you wait a day or 2 before doing anything ,just disconnect the co2 line and see if there is still some air getting trapped or not.if it become less noisy ,then you need a stronger filter.

I suspect the noise you keep hearing is air trapped in the filter flowing back up into the reactor. If so, I'm surprised the filter still starts up with no problems in the morning. I would definitely put the reactor on the output side of the filter, not the inlet. Any excessive CO2 will then be pumped up into the water, rather than hitting the filter as a big bubble where it can cause problems.

My filter pumps 500 LPH, surely this is enough as my tank is only 29 US Gallons?? Ok well its 8am here right now and the excess gas must of been dissolved as all I can hear is silence, I guess that this means my LPH is ok.
The noise is definately coming from the reactor, I've put my ear right up to it and the filter to check. I used to have my CO2 pumped into the filter which was also noisy and caused some airlocks, this is why I decided to build the reactor.
Ok I really think we have our ins and outs mixed up here. I have read on other posts that the gas should travel up against the flow of water to be dissolved. If I connect the reactor to the output of the filter all that is going to happen is that when a bubble is released it will be pushed straight up by the water flow and into my tank without being dissolved. Gas travelling up the inlet side will not go into the filter as gas rises, am I getting this right?

I think the problem must be the way I have the CO2 inlet positioned, I think the gas must travel all the way up the reactor to be dissolved. I'm going to reinstall it upside down to test this before I drill any more holes...

The reactor should/must be on the output of the filter. I think that just making this change alone will make a huge difference.

You can switch it to the return side of the filter--the bottom hose needs to go on the top and the top hose needs to go on the bottom. You will probably need to get rid of the straight barbed fittings for barbed elbows, and you will probably need more/new hose. Also, a 20 degree tilt often solves the problem.

You can also remove the straight barbs, plumb in a couple of pvc elbows on each end and then reinstall your barbs.

Not a big deal--its easier to do it than it is to think about it.....

HTH

Thanks Guys...

So It seems my input theory was totally wrong, sorry that I doubted those that replied earlier. Now I've changed the reactor over to the output, primed the filter and........ !#[email protected] the priming lever has snapped and there's water coming out all over the place!!!!!!! Now I know why people have said stay away from eheim ecco's, wish I found that out before buying the bloody thing!

Ok well all is not lost its only one of the handle clips that has broken so I'm now in the process of glueing it back together with Rapid Epoxy. I've got my filter media in a bucket of tank water and an air pump keeping the bacteria oxygenated, fingers crossed this will stop it from dying.

So anyway once I have fixed the filter I will be able to test the right way of hooking this reactor up and hopefully have a noise free aquarium.....

Ok so i managed to get my filter up and running again and has been leak free all last night. I now have the reactor on the output side of my filter. The 45 degree angle is at the top so the reactor is sitting at about a 20 degree angle, the CO2 line is now situated about 3" from the bottom of the reactor.

The gas has come on by the timer at 10am and already I can hear and see bubbles escaping through my vertically orientated spray bar, as I suspected it would. What have I done wrong here?

The photo below shows how I now have it set up.

You want the water to be going against the co2.
Water enters filter from tank, exits filter, mixes with co2 at top of reactor, exits at bottom of reactor, enters tank.
MS paint to the rescue..


You could also try lowering the bubble rate to stop the gas buildup. You may find the lower bubble rate is sufficient with your new reactor.

B2K2,
I didnt follow closely but seeing the last picture straight away giving me the urge to say the placement is WRONG. The flow must be the other way around. If you set it like the way showed in photo, CO2 will not get dissolved and wasted to the spray bar, then escaped to atmosphere.

I use 4" pipe because I want 100% dissolution in shortest time, and it can held up torrent of 10+bps to feed my 260 gallon tank. No bad issues right here, just significantly improved tank from replacing dinky 2" internal reactor with a bigger gun. You see also I have a very big buldge to contain large quantity of CO2 and run the thing with a dedicated powerhead. Water goes in from the top and exit from below.



I'd say for you a bigger diameter pipe like 2.5" or 3" would be a lot better.

One more time. Water flow should be from TOP to BOTTOM.

Reactor should be on the OUTLET side of the canister.

CO2 injection should be in the top 1/3 of the reactor.

Doing all these allows physics to do the work of dissolving the CO2. You have the water flowing down, the CO2 trying to rise.

The hose coming out of the canister filter needs to go to the TOP of the reactor and the hose going to the aquarium needs to be attached to the bottom of the reactor..........

But first, turn your reactor Back around to the way you had it and then add the elbows that I mentioned in my last post.

Ok I have now fixed my filter and have set up the reactor correctly using right angle elbows. Thanks for the diagrams Lorenceo and medicineman, I was looking for something like that for ages.

Well it seems to be running ok but I still have a slight trickling sound, maybe I just have sensitive ears. I made sure the reactor was burped and it was running silently before turning the CO2 on, so it is definately gas that I can hear. All the plants are pearling very nicely even under 1 WPG as I'm running a low light setup.

Well I guess the slight noise is something I will just have to put up with, does everyone else experience a little noise?

Also I have just noticed tiny bubbles coming out of my spray bar, is this normal also?