ooh cool i used to have one on a 7g minibow.
most silicone tubing is bad its too soft.
if you want a small one you can get some tubing at a model shop its teflon and narrow, you can use 2 20' lengths wrap it inside a 2" piece of pvc and add 4 bio balls
total length is like 8" which is shorter than the minibow.
even is you do choose to use .170ID or .250ID tubing you can power them with anypower head the low flow rate will allow you to use most pumps for both the coil and waterflow.