I've been wanting to make these for a while now, and have had the material laying around for a while now. I couldn't get the silicone hose method to work, and wouldn't settle for sand grains stuck in the tubing, so some down-time, frustration and creative thinking led me to this idea: salt. If any salt remained partially embedded in the plastic it would easily dissolve. Here are the results:
Before: Ugly Rena Plumbing
The first pair I made came out ok. I ended up keeping the return, but I really didn't like the way the intake looked. My girlfriend suggested I try to make the slotted ADA style intake, but I'd heard that they're extremely fragile. I had a bunch of left over plastic so I decided to give it a try:
Much better. Here's what I did: Taped off one end of a tube with masking tape, filled the tube with iodized salt (was simply what was available), shook and packed it, topped it off to within an inch of the top. Then I taped off the second end, laid the tube on a flat, stainless workbench, put one end in a vice, and slowly heated it with a heat gun. I bent the tube around a 1" brass pipe to get a nice curve, slowly working different parts of the curve.
For the slotted intake I pinched off the end with pliers, leaving a small space for priming with an airline tube, and used a hack-saw to make tiny slits in the tubing. Seems to be working great so far. If only i can get the balansae to grow in around them they would be almost completely invisible. Next I'm going to make some for my nano cherry tank.
Thanks to the following for ideas and inspiration, and anyone else who i may have left out (sorry if I have).
curare, wasserpest and unirda