Hi Findi,
Very interesting Blog, I will definitely be heading back there later to read other Blog posts.
I think that undergravel filters can be a great solution to filtration, especially when maintaining a large number of tanks that each require independent filtration.
I know in the your Blog post you mention that it can be suitable for larvae and smaller newts (you mention Eastern Newts), I think many are still reluctant to use undergravel filtration for adult newts. This I believe is mainly because people are concerned with the adults ingesting the gravel. Although you can always choose a larger stone size, they will contain a variety of stone sizes and there can always be the risk that they might accidently swallow one.
I have only uses undergravel filtration in one tank that was for tropical fish though, I never felt that it kept the aquarium overly clean. I never thought of cleaning the plates by connecting a siphon to the output tube before though, seems kind of obvious now!
