I know what you mean about the filter, I must admit that I run an eheim ecco pro cannister on my C. pyrrhogaster tank, but only because I know it's over stocked at the moment with my adults and seven juveniles I'm raising and I don't run one on any of my other newt tanks. If you keep the stocking sensible and there are enough plants the filter really is doing more harm than good for the reasons already given.
I'm not that knowledgeable when it comes to natural aquariums, but as I understand it the plants will in fact remove ammonia directly from the water along with nitrates.
Remember you are trying to provide conditions that are optimal in every way and as Azhael has said any kind of water movement will upset the newts and possibly compromise their rehabilitation. If they do recover and become fully aquatic they will probably probably tolerate a slow turnover cannister or air driven sponge filter but they will be perfectly ok without one.
I'm not that knowledgeable when it comes to natural aquariums, but as I understand it the plants will in fact remove ammonia directly from the water along with nitrates.
Remember you are trying to provide conditions that are optimal in every way and as Azhael has said any kind of water movement will upset the newts and possibly compromise their rehabilitation. If they do recover and become fully aquatic they will probably probably tolerate a slow turnover cannister or air driven sponge filter but they will be perfectly ok without one.