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EXTERNAL INLINE CO2 REACTOR

I was running CO2 into my Ehiem 2026 canister
and was having trouble keeping CO2 levels high
enough in my 75G heavily planted tank. Pumping
more CO2 caused a lot of burps and sometimes the
reactor would airlock.It was time to use a CO2 reactor,
but I didn't want to spend too much so I decided to build one.

My DIY CO2 reactor is based on the Barr method,
but I hate adding more equipment into my tank,
so I designed it to run inline with my canister.
I made two reactors, the only difference between
them being the barb size. I'm running them inline
with my Eheim 2026 and 2213 on the filter intake.

Parts used:
One 10" length of 2" diameter PVC
Two 2" - 1/2" (female) reducers [the endcaps]

Three 1" hose clamps
Two 5/8" hose barbs (male)
Teflon tape
Five Bioballs (from Local fishstore)
One airline connector (from Local fishstore)
PVC solvent glue
Plumbers goop [waterproof resin glue]


Initially I used a different design that would be
inline on the filter outflow - only clean water
enters the reactor, less muck to deal with,
but i noticed a significant reduction in the
flow rate. I ended up putting it inline on the
filter inflow. As I write this article, I've been
running the reactor with no clogging issues yet for
2 months. If it does start to clog up, I'll simply take
it off, run some water at high pressure through it to
clean it out and pop it back on. If you're worried
about it - you can use a prefilter on the intake tube.
That will catch any larger pieces of debris.

Almost everything was bought from Lowes but Home Depot
carries most of this stuff too. Under $10 cost per
reactor for parts and took me about 20 minutes to put
most of it together with PVC solvent glue and a
little 'Plumbers Goop' (can use epoxy) for the
airline connector. I put Teflon tape on the barbs
before I screwed them on to eliminate leaks.

I chose not to attach a 'hang on' piece, instead I
secured the hoses with clamps. Much cleaner.

I'm getting 100% dissolution. Now I can crank up my
CO2 without worrying about air locking my Eheims.
No more burps!

You can use cheap plastic scrub pads from the dollar
store if you can't find the bio balls.
Just make sure they're inert.

Good luck!