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stevenjohn21 09-13-2012 07:09 PM

Rex Grigg style reactor not working
Ive had my Rex style reactor on my XP-3 now for 2 days and although i dont see a mist of C02 bubbles i dont see it working very well. Today i decided to experiment and turned the needle valve open allowing about 20bps ! and my drop checker only turns to a light green. Fish are still very much active.
Does someone have a picture of there setup so i can see what tubes run where ?

HD Blazingwolf 09-13-2012 07:12 PM

what size tank is this?

do u have an airstone in the tank? hos much of the co2 is actually dissolving? is there a giant co2 pocket in the reactor? if so its not doing its job well

stevenjohn21 09-13-2012 07:17 PM

the tank is a 75 gallon standard, no airstone just Rena XP-3. C02 seems to be dissolving as ive sat and watched the output for about 20 mins and dont see any bubbles (maybe every now and again)
I turned the reactor and shook it so there shouldnt be an airpocket.

RainSong 09-13-2012 07:18 PM

Mine has worked very well ... it is 1 year old.

The outflow from your canister should go to the top of the reactor. The bottom of the reactor goes to the fish tank.

stevenjohn21 09-13-2012 07:23 PM


Originally Posted by RainSong (Post 2010078)
Mine has worked very well ... it is 1 year old.

The outflow from your canister should go to the top of the reactor. The bottom of the reactor goes to the fish tank.

Thats how i have it setup but the reactor is not standing straight up. Its at an angle like 10 O'clock with the c02 entering the top. Do you think that with it not being straight up its causing a problem ?

RainSong 09-13-2012 07:36 PM

There are only a few places for the CO2 to go:

1. Dissolve into the water -- a good thing.
2. Collect at the top of the reactor -- would become obvious at some point.
3. CO2 leaking -- sounds quite likely in your case.

I do not think a slight angle in the reactor would hurt it. I would first try to eliminate the possibility of leaks.

Also, what type of tubing do you use from your drop counter to the reactor to carry the CO2?

stevenjohn21 09-13-2012 07:47 PM

I thought i might have a leak but i used shaving foam around the seals and cant find anything to prove this. My airline tubing is Fluval's micro flex black tubing

RainSong 09-13-2012 08:04 PM

My understanding is that airline tubing is not the best for CO2 and that it can lead to leaks (not necessarily around the seals).


I use Polyethylene tubing.

Curt_914 09-13-2012 08:14 PM

When my reactor was hooked up it did just fine. I dont use airline tubeing as the silicone tends to bleed co2. I use a co2 specific tubing. It is around $4 a foot but worth every penny. You should be able to get it from big als.


HD Blazingwolf 09-13-2012 08:23 PM

regular tubing works fine

a 75gallon is a lot of water to saturate with co2 and ur bubble size can contribute a lot to misconceptions. if i had a bubble counter with that super small opening id probably be running 20 bps in my 29 gallon
as it stands with an open airline im at about 3-5 bps.. its hard to tell but they do come out fast

Jeff5614 09-13-2012 08:46 PM

I used a reactor for years and they're all about flow. A reactor of this sort really cuts down on the flow from a canister. If I neglected filter maintenance I invariably paid the price with stunted growth (check out my journal and you can find a few pics showing this).

I think the issue is flow in the tank. I don't think a lone XP3 is going to cut it, especially with a big PVC reactor, as the only source of water movement in a 75 gallon tank that has or will have a lot of plant mass. You're going to need a filter that moves more water, a second filter or a circulation pump or two such as a koralia.

If your dropchecker is on the opposite end of the tank from the filter output try moving it closer and see if there's any difference.

HD Blazingwolf 09-13-2012 09:26 PM

glad to see ur still around jeff!

Jeff5614 09-14-2012 12:05 AM


Originally Posted by HD Blazingwolf (Post 2010245)
glad to see ur still around jeff!

Where else would I be? :)

isellcars 09-14-2012 01:49 AM

I also have a Rex style reactor on my return from my sump tank. Except I have the return going in the bottom and out of the top to the tank. I am pushing about 800gph and I do see the fine co2 bubbles going into the tank.
My thing is no matter how much co2 I push in my drop checker stays blue. I do have it set up on the opposite side of the tank. Is this a good idea or not? Not sure if it makes a difference but I do have lots of co2 bubbles all over the drop checker.

milesm 09-14-2012 03:58 AM


Originally Posted by isellcars (Post 2010619)
I have the return going in the bottom and out of the top to the tank.

therein lies your problem. the input should be on the top, output on the bottom.

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