Thank you for the replies!
There's a filter under the bark in the rear right. I change half of the water every month; some further change occurs because of the monsoon misting system which adds clean water daily. I make some deeper cleaning occasionally and once a year a complete cleaning, also of te terrestrial part. Plants help a lot in keeping the water clean and stop algae. Basically, is a low maintenance tank..
PS my babies are growing.. rear legs are almost done! I'll let you know when metamorphosis is over!