Grimsby have serious disciplinary problems after having three players sent off in two games.
Two of them midfielders, Des Hamilton and Iain Anderson, now face three-game bans for being dismissed for serious foul play.
Grimsby player manager Paul Groves defended Anderson who he said is:"An honest lad who made a genuine challenge for the ball and was amazed to be shown the red card." After taking a 1-0 lead in the first half and then losing Anderson in stoppage time Grimsby conceded two soft goals in four second-half minutes.
Despite Vale being the better side early on with Grimsby keeper Aidan Davison making three great saves it looked rosy for the Mariners when an excellent cross on the run from full-back Marcel Cas was headed home by striker Mick Boulding on 37 minutes.
But Grimsby had to alter things in half time with striker Laurens Ten Heuvel making way for player-manager Groves.
Ironically Grimsby's best spell of the game came at the start of the second half but a double substitution by Vale manager Brian Horton did the business for the Valiants.
Striker Stephen McPhee equalised on 64 minutes when he latched on to a backpass and rounded the keeper to score and then four minutes later Grimsby were caught out from a free-kick when young sub Billy Paynter converted from Ryan Brown.
Grimsby tried to pull things round in the closing stages with sub strikers Darren Mansaram and Jonathan Rowan thrown on and Mansaram missed a good chance to equalise.
But it was Vale who almost had the last word when Grimsby were caught with nine players in the opposition half but two Vale players made an absolute hash.
So with two wins from their opening games Vale sit pretty in the second division table, but with a new-look line-up Grimsby are finding in hard to adjust to life in a lower division after relegation from Division One.