Hello and welcome to FF! Well Keeshe... sorry to be the harbinger of bad news to you; but your present enclosure is a disaster waiting to happen. UTHs in frog tanks do not belong to the bottom since frogs natural tendency is to burry in order to cool off. You can use on the sides if so desired; but they are inefficient done that way. A basking type light on a dimmer dome is a much better choice and will help provide the needed 85F basking spot.

As Bill mentioned; a false bottom or drainage layer to collect extra water is not an optional necessity. No matter which design you go with; it is necessary to prevent the substrate from flooding and becoming a bacteria breeding bog. Talking of substrate, if using live plants need ABG type soil since shredded coco is not a good substrate for them.

Recommend visit the Vivarium section and search for Bill's build threads; specially one called Mantella Paladurium. Know is crazy to tell you to tear up your vivarium and start again; but it will save you lots of problems in the future to start it right now .