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CO2 reactors???


10 Apr 2008
Coventry, UK
Erm...ive never used these, but I am think ingthey might be ideal over my current system whihc is a JBL diffuser.

my current aqaurium is 400 litrs and i may upgrade to an 800litre. I have seen the Aqua medic 1000: http://www.aquaticbiotope.co.uk/Scripts ... roduct=827

I am not sure though what 12/16 mm connection hose mean. Does that mean it can connect to 12 and 16 mm internal radius hose?

I have a fluval fx5 which has 24mm hosing and an Eheim 2080 which has 16/22mm (i get confused what does that mean, its 16mm internal radius?).

So this works by attaching the reactor to the inlet pipe of an external filter? Is there another way of doing it so that you dont reduc filet flow. Can you use a powerhead ( dont know how that would work lol) or an external pump? hmmm maybe just another smaller filter....think clive mentioned that.

Do you guys have links to any other co2 reactors?



Expert/Global Moderator
11 Jul 2007
Chicago, USA
The smaller number is the internal diameter of the hose while the larger number is the external diameter. 22 mm minus 16 mm = 6 mm so that the wall thickness of the plastic hose is 3 mm. This hose fits comfortably over any spud having an external diameter of slightly less than 16 mm (0.63 inch). A 12/16 mm tubing has a wall thickness of 2 mm (16 minus 12 divided by 2) and fits comfortably over any spud having an external diameter of less than 12 mm (0.47 inch).

As you can see by the hose sizes the FX5 it's flow rate is substantially higher. Look at the diagram on this Cal Aqua page=> http://www.calaqualabs.com/Inline_diffusers.html

Can you see that it has three spuds? The bottom spud is where you connect the filter outlet. The top spud is where you connect the hose that enters the tank. Filter exit flows from bottom to top and around the ceramic disk in the middle of the bulb shape. The third tiny spud is where you connect the CO2 line. The CO2 exits the disk in tiny bubbles and enters the water stream which dissolve on their way to the the lily pipe or spray bar in the tank. The water actually flows around the disk and the pressure drop helps to pull more gas into the stream. In this design the bubble flow in the direction of the water flow.

In the AM1000 the CO2 bubbles rise from the bottom of the reactor against the flow of the water which flows from top to bottom. This gets the gas into solution with greater efficiency but the penalty is steep. The flow reduction, is much greater than in the Cal Aqua design. Both these designs are incompetent due to the heavy penalty imposed on flow due to their very small diameter spuds. Ed Seely has a DIY design that you might find useful. Check the Hardware section. None of these designs were made for large tanks so you will be forced to use at least 2 and probably three. The Cal Aqua is elegant but difficult to clean - and is delicate due to glass construction. The AM100 is constructed of a more sensible plastic but is more fiddly.

You cannot use a powerhead (which needs to sit inside the tank) on these external designs.

Hope this helps. :D


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