[Zapins]

Assuming you aren't just running out of CO2 (when was your last refill?), then perhaps there is a blockage between the needle valve and the regulator. If you have a small metal object like a welding tip file or perhaps an unfolded paperclip you could disassemble the needle valve from the regulator and clean it out.

Otherwise I'd guess it was the tank simply running out.

 

[ipkiss]

I can't say for the UP Aqua diffuser but when I ran a fluval diffuser, because it requires a decent amount of pressure to push through, took a little while to stabilize. Then, as it aged, I think it started to clog or something and created some back pressure too and messed with my bubble count.

 

[goneRogue]

50 psi is awfully high. Can you get that down to 20-30 psi?

 

[Zapins]

How long has the tank been used for?

 

[hello_rockview12]

All of the components are new except the regulator which is next to new. There shouldn't be a blockage as I made sure it was clean before I assembled it. I'm running it at 50 psi because I was under the impression that the atomic diffuser needed 40 and figured 50 wouldn't hurt. It's been running for about three weeks now, 6 hours a day. Perhaps it is the cylinder itself as I borrowed it from a friend to try it out because I was having trouble finding one without a contract attached and they want you to consume it at a much higher rate than I would on my single aquarium. It could be running low. High pressure says about 780