co2 reactor and internal pump???

With CO2 injection you will probably use a reactor inline, or a diffuser of some sort in the tank. The diffuser option will put CO2 bubbles in the tank. It will be less efficient at dissolving the CO2 and of course the bubbles will be visible.

This is a decent compilation of the methods available to you:
http://www.plantedtank.net/forums/showthread.php?t=423713

If I was dealing with a tank as large as yours I would definitely consider a canister filter with a reactor inline. If you already have your filtration covered then you could consider an additional smaller canister filter just for the purpose of dissolving CO2.

Even better, for that tank size. An external sump with wet/dry filter would work at best. Them you can put all the pumps you want inside the sump, out of your tank.

Thanks. But both suggestions are no go. Dont have room under the tank for sump and i dont want a canister filter, dont have room for it either. Next tank im getting i want a sump. I also sleep very close to the tank so dont need more sound from it.

get an external pump and run your reactor in a closed loop. only equipment in tank will be the input and output lines which are easily hidden.

I might get an external filter but mostly to use with co2 reactor. http://www.allpondsolutions.co.uk/a...ilters/aquarium-external-filter-1400-l-h.html

Will this do the job?? I got a big filter behind the background that works perfect.

I am also thinking of getting this http://www.co2art.co.uk/collections...l-stage-regulator-and-solenoid-magnetic-valve

Is that okay or are there others i should look at instead??

I got the external filter and i dont think it would be capable to use with a co2 reactor. Its also noisy

Is it possible to drop the pump inside and use it with an external pump standing beside the canister, like the eheim compact+ or something like that??

I used an internal filter and a Rex Griggs reactor that hangs on the back of my 40b. Works great.

Link