i had the same problem. i has bed-a-beast over top of my soil. and they would romp in it and brag it into the water making it lookg awful. and changing the water every other day did help. So i went into the woods and goot some moss and covered my alnd area in it. (see picture above, like its easy to miss...) I really recomond this set up if you feed the frogs by hand. if you do not a cricket could make its way under the moss and die. since i put the moss in about a week in a half ago my water has improved by 110%! When i changed the water before it was full of nasty soaked bed a best. no i soak up just impurities.