Just a quickie, we have purchased a 400ltr tank and it has a threaded plastic 1" connector on it.I cant find a way of converting this down to 12mm nor can all of the shops i have been in So if i remove this and put a new one in what do i need I cant find tank connectors or fittings to connect up to the 12mm pipe! HELP!! CAN I ASK WHY YOU ARE GOING DOWN TO 12 MM