<a href=showthread.php?s=&postid=8048632#post8048632 target=_blank>Originally posted</a> by Reefflections
Just having a real hard time getting the bubble count to run really slow/without totally stopping.It's a dual chamber My Reef Creations.And also want to CO2 to break down the media
Issues with unstable CO2 flow are reduced to three posibilities:
a) Quality of the regulator: for a low stable flow a stable low delivery pressure is required from the regulator. Unfortunatly quality dual stage regulators required to do so are rare in the aquarium business so we need to live with what we get. Usually a single stage like the ones we use will surge up and down when trying to be set at a low discharge pressure (Less than 20 psi). In other words it will open, rise the pressure then close and until the pressure drops again it will open again so instead of proportionally regulating the pressure it acts like an on off valve which breaks havoc with the stability. Try setting the outlet pressure between 25 and 30 psi in the outlet gauge while the flow is running.
b) Unfortunately the higher pressure will make the needle valve more sensitive, a very small turn may imply a rather large change in the bubble rate. Try adjusting your bubble rate and if it is a bit too fast, instead of readjusting the needle valve use the regulator's pressure knob to lower the delivery pressure a bit and vice versa.
c) Another source of issues is usually the CO2 check valve or the absence of one. , DOmetimes the check valve needs too much pressure to open thus also generating surge. Pressure in the line increases, vlave opens pressure drops and so on, if you notice this behaviour try a new good quality check valve. (D'Nearle is my preferred one)
Finally changes in temperature can change the adjustment. As the temperature around the needle valve changes the aperture between the needle and the seat changes and the bubble rate changes.. This effect is anoying but not critical, your reactor will operate at various PH levels troughout the day but in overall it will still in average deliver the required alkalinity.
So in summary:
Try playing with a combination of regulator pressure knob and needle valve to facilitate the adjustment, review your check valve and finally, a PH controller can make your life a lot easier as it will alow more deviation in the bubble rate than if you do not have one.
If everything fails then we will need to work toward achieving stability inside the reactor and the recirculation pump. (Media size, media mushing, pump capacity, trapped air or bubbles, feeding method and so on)
I really don't even test my Ca anymore, I do the Alk test and if it's where it's supposed to be I know the Ca is in line as well.
