Fresh2o
Aquarium Advice Addict
OP - sorry to barge in again. Interesting stuff here. The CarbonDoser regulator that jehenry mentioned is toted as "the best in the world". No mechanical needle valve (it uses an electronic valve), it also has no solenoid valve. The conventional bubble counter is replaced with a flashing LED indicator. Yes, a little pricey but competitive with several GLA models price wise. Oh, the confusion sets in...