Originally Posted by Rex Grigg
And as I told you I had tested the Fabco years ago. And the unit I tested was crap. I would now suspect that someone had gotten out of hand using it as a shut off valve. You convinced me to give them another try. They are a great needle valve. I will be buying them 25 at a time.
But you seem to be really hung up on the pH issue. And it's not an issue so I can't understand why you are so hung up on it. You claim that it's better for the fish to have a more stable pH. Yet you have in one way acknowledged that pH changes caused by CO2 do no harm to fish. But you still insist that a stable pH is better.
Why are you still harping about pH? Re-read my posts (again several times). There are many other advantages
to 24/7 injection. I never said that the larger pH fluctuation is lethal to fish. The goal of any experienced aquarist is to maintain a clean and stable water chemistry. In the case if 24/7 injection, we can accomplish this with less equipment and greater overall system reliability. If you want to split hair about the cost of CO2 injection, then I submit that you will have to pay an additional $3.94 annually in electricity to run the solenoid/timer unit (3 watts 24/7 at 15 cents per KWH).
designer would have zero problem identifying a quality needle valve by visual inspection. Any hardware can fail, right out of the box. If you paid $1500 for a Nikon digital SLR camera and the unit would take lousy picture, would you conclude that this line of camera is junk? Furthermore, one can often request a sample of the Fabco NV55 from the local distributor, free of charge. I would expect better judgment from an individual who claims to have may years of experience in this hobby.
Look at the posts in this forum about people with CO2 rig at 30 psig regulated pressure and still unable to achieve a stable bubble count. Virtually all of these problems will go away if a high quality needle valve is attached directly to the regulator. The inclusion of solenoid, pH controller, pH sensor, and other bells and whistles can only add more complexity to the simple task of metering the CO2 to the water column.
Anyone can build a great CO2 injection rig. Start out with a $40 beer regulator. Add a $20 Fabco NV55 needle valve. Miscellaneous brass connectors to attach the NV55 to the regulator will cost another $5. To prevent water from contaminating the needle valve and regulator, you'll also need a $5 one-way check valve. Final cost is $70. You'll save at least $50 with this DIY approach. The only tool required is a crescent wrench.