i have one im using as a second chamber for a pm reactor i think if you already have all the stuff to build it then it should be real easy just add in a few holes and pipe and pump but if you have to buy from new just the cost of the eheim 1048 pump and the phosban reactor will run you $100 for both online but even more at retail stores :shock: .... if you are just needing a quick cal . reactor thats easy and cheap i would just buy this and it comes with the pump.
I don't believe the phosban reactor can handle the internal pressure from CO2 being added. CO2 tends to be kept around 12 to 20 PSI, and the reactor can handle something like 6PSI if I recall correctly.
If it works, be sure to let me know so I can let others know.