I built my own cerges reactor based on the instructions from the barr report article linked below.
How To Build A Cerges CO2 Reactor
barrreport.com
My modifications included using plastic pipe fittings, and cutting a small piece of 16/22 hose at a 45degree angle to fit inside the head to divert the inlet flow downwards.
I also removed the foam inside the reactor as it blocks over time and doesnt seem to make any difference to the diffusion.
I find it very quiet and no bubbles in the tank. Total cost including fittings was £25.
I originally had it on a 300l tank and connected to a 3000l/hr pump and there was some some noise if the CO2 rate was high. I found the clear acrylic became frosted after a while even though there was a prefilter on the inlet. Now its on my 200l powered by an Oase 850 and there is no noise except for a few minutes when air gets in the system after cleaning.
I didn't take any photos during assembly but this is one insitu.
View attachment 198313
Hope this helps.