water dish would work, i have those in almost all my tanks, i like that you can go with any size fits your frog, it is perfect size/amount of water balance.
as for the rest, you need to clean not part of your substrate but all of it once a month! and stir it at least once a week.
so that is how I do it:
-place a frog in a bath with warm dechlorinated water
- take everything out of the tank, substrate to the garbage, decor - rinse with very hot water.
- prepare a new exo earth, while it is expanding, wipe everything inside the tank with just water, then wipe out by zoomed ( or lately I use veterinary grade disinfectant), when done, I spray with some water and scrape all water residue from the glass, then i use terrarium cleaner by Zilla , it gives very clean finish to a glass and some resistance for future water residue, after everything is done, i put substrate, decor ( exactly the way it was before) and place a very happy frog ( cos she LOVES her bath) in her water dish and close the doors.
- repeat with next tank lol and then the next one... and so on and that is how I spend one day a month.unfortunately only one my frog is happy with the whole thing, all the rest hate every minute of their bath.
that is my terrarium cleaner, love it!
http://www.amazon.com/Zilla-Terrariu.../dp/B001F9ATFG