Wheres SuperColey when you need him
Lol, there are plenty of knowledgable people on here. I'm maybe a little more vocal. lol
When you've made all the knobs on the regulator 0, do you twist the cylinder wheel thingy just one full turn?
Open the cylinder up until you hit 1.5bar (with the needle valve closed)
when you 'fire' the canister I take it you just do it with a regulator in (solenoid too?) then connect everything and fiddle with the regulator to start with 1bps and work it up? I read on the sellers website you can times the KH by the litres in the tank to get an estimate which was 5bps for me.
Nope. you 'open' the regulator with the large knob and then leave it alone. From there on you are using the needle valve. No idea on the 'firing part. I never used FEs I used disposable welding cannisters.
No idea on this 'estimate' theory. You start at 1bps and then slowly work your way up or down until the DC is saying 'bingo'. Can take a couple of days to get it dialled in first time and from then on you pretty much know where you are. Can take a couple of tweaks though as the 'back pressure' can change slightly when you disconnect and reconnect (cleaning diffuser)
The 2 hour prior concept is used by the majority. Basically the plants do all the hard work in the first few hours. therefore people want the CO2 in there ready and can then turn it off well before the end of the photoperiod. Think of it as you get somewhere have a huge meal and aren't hungry for the rest of the day.
Some people who 'trust' their abilities may only have the CO2 on for 1-2 hours before and then turn it off 4 hours in. Most do 2 hours before lights on and then off 2 hours before lights off. Tom Barr (who as oyu would expect knows his stuff on this and more than likley has his CO2 setup better than anyone else in the world) turns his on at the same time as the lights
I would go for 2 before and 2 after. Once you're happy the setup is fine (circulation, etc) then you can adjust your method if wanted. I used to have mine turn on half an hour before lights and off 4 hours before lights off.
~Forget the estimates. CO2 can kill fish pretty easy. Always start cautiously on the low side and work your way slowly up. Keep checking the DC every 2 hours for the first few days and 'tweak it' until you are happy it is not going yello but is reaching 'lighter green' push it to limeade colour when you are confident but that is pretty close to yellow so hold off until you are confident.
Forget anything that ever tries to tell you the bps. Your bubble counter may give 1 bubble to 5 in mine
different units produce different size bubbles.
Good luck, take care and keep monitoring. CO2 is a big step but if you get it working well is a huge leap from being a gardener to being a 'technician'. You will be pruning a lot more than you think
AC
If I don't return, my fish will need a new home 
very reassuring!
