anti siphon
the best thing to do is to get an anti siphon tube for your tank its about 10$ canadian (whatever that is in punds or us dollars) it prevents liquid CO2 from entering your gun. An expansion chamber will help significantly. I suggest an ACI 4 or 6 stage expansion. Plus at this point in you paintball "career" a nitro tank would be a waste of money. Nitro is for guns like cockers mags and angels which can't run on CO2 very effectivly because they fire too fast and at a low pressure. If you do decide to get nitro despite my suggestions make sure your field has nitro fills first.