re dive cylinder testing
dive tanks from new with dive valves, ie those without built in vent and gauge are due the following, visual after 2.5 yrs then hydro at 5 yrs from manufacture as they are still technicaly capable of being used underwater so come under those regs.
if a cylinder has a pillar valve with built in vent and gauge it is deemed for surface use only and needs a hydro every 5 yrs from date of manufacture.
if you have an old tank it will only get a 2.5 yr test from its next hydro test if deemed a dive tank or 5 yrs if deemed surface, the main differance is the valve which tells whether it is for surface or underwater use, paintball cylinders are due if they are of carbon construction are every 3 years on fibre wrapped and 5 yrs on hooped wrapped from date of manufacture.
hope this helps a bit
Trevor