Like Zoomie said use a spray bottle for misting. The fog effect is cool in your terrarium and does increase humidity some but hand misting with a spray bottle will also keep your plants watered better and when you hand mist you are also getting a good look at your frogs/plants health. Auto mist systems are great too,but if you are home daily use the spray bottle.
I currently hand mist once a week because there are just plants no frogs right now I like the idea of a self sustaining system though I want to add a mister and I have a fan ready. There are 2 waterfalls so it’s not that its lacking humidity it’s actually perfect but I want the mister and the fan to be timed and go off every few hours. so there is movement in the air and it doesnt get stale and I want to make my pond smaller I have an older pic I can post then I’ll get some new ones tomorrow I lost some plants and got new ones so I won’t waste time posting the foliage