Take care with this set though, I emptied a bottle when the solenoid sprung a leak. Following a move from the reactor to a spiro diffuser, the increased pressure showed a leak at the solenoid where they had put a lock nut & washer in place which prevented the seal from making. I alerted them to their design fault but got no feedback.
Also, check where you can get bottle refills - I've now got 2 bottles that nobody will refill (need pressure test certificates,etc) so my CO2 now runs off a pub bottle (probably got about 5 years worth of CO2 in it !!) which including bottle deposit (refundable - Â£10) cost me Â£23. To be honest, I'm setting up my son's tank and I'm eBaying the items separate to go with a 2kg fire ext.
Sounds like you got a bum one to me, I've got 2 and neither of them have ever given me any problems, ever. I run mine on FE's now and I can say they're far superior to both JBL's, Aquatic magics and D&D.