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View Full Version : Smooth U-tubes vs Squared connected pipe


Vincerama2
07/08/2003, 01:03 AM
Hi!

I'm building an overflow box and I have some 1/2" PVC (Yes, I know, small diameter! It's for a 10g with a 10g sump and a small pump) Anyway, I was originally planning to make a siphon tube by connecting 3 pieces of PVC pipe with two 90 degree elbows. Then I decided to try making a U tube by heating the PVC (sched 40) over my stove. Well, the U tube works pretty good, and was not that hard (be careful when doing it!). The only tough part was bending the pipe slowly, in small sections, otherwise the pipe would flatten in the bend. I suggest having a bowl of water to hasten the cooling, so you can get on to bending other parts.

Anyway, the tube works pretty good, but the shape is not very compatible with the squareness of the boxes. So I was thinking of carrying on with the squared connected pipe plan. But I noticed that the elbow/pipe connection is actually not very smooth. Would that connection cause air bubbles, or cause drag in the siphon tube? Since I have some spare pipe, I am also going to try heating up a section and making a more square U tube without the elbows.

Does it matter what shape the siphon is? Anybody know?

Vince

skipm
07/08/2003, 09:01 AM
I would think that the elbows and pipe should make a nice clean tube, if you are worried about the flow restrictions/turbulence that will be generated from the elbows then go to 3/4 inch pvc for the tube. You can also find the 1 1/4" premade u tubes for about $5-$7 in most fish stores if you would rather not mess with making one. Good luck, Skip