I feel you. 43c in Melbourne today and my tank go to about 27.7c.
Not as bad as 34c but all i do is either open where my sump and light is and just run a fan through it. Or put ice in your sump.
My tank sits at about 25.5c normally, So a 2c isnt to bad of a jump, Luckily i havent lost anything.
Good luck to you, try turning your heater down to about 24.7.
Your hammer may come back, I thought Leathers were abit more hardy then that.