[ChrisGotSteeZ]

i didnt know where else to put this... but there is like a hair line split there,

will that cause my tank to leak? how should i go about tightening this?

i have a 45/4500 that is nice and flush without this little hairline split.

i have tried to back out those screws... and screw it in... but it is stuck, and stays there with this little split....

will the tank still work? or is it going to leak?

[Tabris17]

There should be an o-ring between the reg base and the bonnet so it seals the threads. It's probably just how the reg and bonnet come together that forms this 'split', I wouldn't be worried about it too much since it's so small.
And only way to figure out if it's going to leak is to put some air in it but I highly doubt it will. Especially since you snugged it down and retightened the bonnet set screws.

[aerosaaber]

Try filling it, if it leaks then go from there.