I started using a citric acid setup about two weeks ago. It looks just like your first link but without the bubble counter. I had read reports of close to a month, 8 hours a day at 1bps. Currently I am running 2.3 bps 24/7 and only getting six days. I bought this system just to experiment with so that's what I am doing. I will need to remix powders on Saturday and am going to try shutting off the flow when the lights are out using a valve I put together. I am also playing around with different reactors to increase dissolve rates. What I like about the citric acid is the output is much stronger that yeast and there is no waiting for the pressure to build up. I have much more bubble count control with the needle valve. I only need to see a huge increase in the time between refills for me to say I like it.