Nepenthes soil problem

[kentosaurs]

Hi all..


I have 2 nepenthes which are potted in potting soil and both have not much problem pitchering just that its not that big.The 2 unlucky neps are my N ventrata and my N mixta x fusca.I don't have any pics on it so i'm gonna try to describe the problem

The thing is that few months back when i water these 2 neps the water comes rushing at the bottom of it even of i water just a little.When i looked at the media looks as if the soil constricted or something.There is an empty space all around the pot..Means a round empty space at the sides of the pot so it looks as if the media constricted or something.Do any of you guys have this problem???And if so any of you know how to deal with these stuff because i think this is why the 2 neps always have very fast drying medias

Ken