ps you have one of the best sigs I have ever read.
Many heaters like this one out there, I would measure the space in the Aquaclear and see if you may be able the squeeze it into the back side of the filter, or cut a slot in the sponge Those nano heaters do not get near hot enough to cause problems like plastic melting.
There is ALWAYS a need for MORE filtration.
40b high tech, 20h low tech, and more 10g than I am willing to admit.
75g in the works (maybe discus high tech?)
SunSun Pimp #85