Great job honda man! I'm anxious to see what your setup will look like complete.
As for that filter, it looks like an aquaclear 110 (formerly AC500) and it's easy to find parts for those filters. They're great for those who like to customize what's in them too, but I only keep 2 sponges in them, and hope to get an eheim soon which will keep mainly bio media in it.
I would suggest you do something similar with your 55g so that you can avoid using a sump, and still get excellent water quality.
I'm surprised the silicone is doing okay after only 24 hrs curing time... I thought it needs 5 days? My only experience with using the stuff is when I made a DIY CO2.
Again, great job.