so I am wanting to build a half land half water tank for firebelly toads in my 29gallon. Ideally I would like to have land on both sides with a "stream" in the middle. I would like to build a rock wall on each side of the stream just by stacking larger rocks. but my question is would hygroballs behind the walls make my water very dirty? Im wondering how to go about filling up the water space with something so I can put land on top. do hygroballs go bad? I do not want to silicone anything because I like to rearrange my tank ever so often. anybody have any ideas? I have been looking on youtube for some ideas but I can't find anything really besides this How to setup a naturalistic vivarium pt1 - YouTube and he doesn't really show it completed with the water running.