Water conditions

Hi, i have problem that has only started since the introduction of bogwood yesterday afternoon, the water has gone horribly murky and the nitrite levels have gone up a lot, this is in another post, i have done a water change but it did not help either problem noticably, does anyone know what is happening because it has ruined the look of the tank. and if so, please could you tell me what i could do to stop it?

Thanks

James

have done another water change and replace filter sponges, the murky look has almost gone annd the nitrite levels have gone down a tiny bit, but not much.