Fitted a new direct hot water cylinder today in work for my boss and tidied up some pipework. Filled Cylinder and had 2 small leaks on the blanking plugs. Drained down cylinder,removed plugs, removed ptfe tape and reapplied fresh ptfe tape. Filled cylinder back up and still get a itzy bitzy weep on the bottom blanking plug . So i goto drain down again tomorrow and do it again. Beside ptfe is there a pretty surefire way to ensuring this small weep isnt going to happen again once i refill. Bosswhite or some other similar threading compound be better than ptfe?.