I found a site in the US that sells two stage regulators with solenoid and PH controller. If I understand the PH controller correctly, that would eliminate the need for a bubble counter?
Thanks,
You don't need a ph controller or a bubble counter but both are nice to have. The ph controller will need to be calibrated every year at a minimum. It can also fail. I like looking at the bubble counter as a visual of the system is working and turned on. I use mineral oil in my fluval bubble counter instead of water, thus lower maintinace because it never evaporates.
Without a bubble counter it'll be like driving by looking in the rear view mirror. You could cause a lot of damage to your livestock before you realize it. A bubble counter allows you to know exactly how much CO2 you are putting in RIGHT NOW, and not have to wait a while to see how steep the pH curve is. I know where you can get one at a very reasonable price.