Re: How do you Unblock a watertank Pipe?
Place cheese in tank. Place rat in faucet, open all valves. Not to worry, the rat will clear out the obstruction.
If you're short of rats, you may need to place hand and eye on the pipe, follow it from here to there, open a fitting halfway through, see which side is blocked. Close that fitting, proceed halfway down the line, try again.
If teflon tape was used to seal any of the threaded joints? That can tear loose and clog things downstream of it, too.