Re: Water feature critters!
It should be remembered also that Whites Tree Frogs usually defecate in their water feature. They are a large frog and it is copious. It is too much waste to be processed in a habitat-compatible "bio active" function.
You have 3 Whites.
Although you are invested in the bioactive modality, I would recommend a removable/replenishable hydration feature. It should be changed daily whether tainted with stool boluses or not. Twice daily is optimum, so make it easy to sevice/remove/replace. Think of it as Drinking Water standing in a warm place. Dawn and Dusk, the only times they should be misted is a good time to replenish the feature.
In doing so you have "management purchased" health insurance for your White's Tree Frogs.