urine problem , what can be done ?

[gerbils4]

hello all I love my gerbils and I dont mind giving them all the space they need in my room , I dont even mind the animal scent they produce the problem is with ... well , their urine . I dont know if it just my gerbils , or maybe all gerbils are like that , but when ever they are in a "new" place the first thing they do is to mark it with their urine the thing is that they consider their place as "new" every time after I have cleaned it ! so in a few hours it has such a smell that I'm having a problem to even get near it . does anyone has this kind of problem too ? do you have any suggestions what can I do ?   thanks hila.