Plumbing question

[spoot]

I see alot of people skip the hose clamps, but I just don't feel safe not using them. I use vinyl on all the connections from my pump. It keeps the vibrations down.

[GreenSpottedPuffer]

Originally Posted by spoot

I see alot of people skip the hose clamps, but I just don't feel safe not using them. I use vinyl on all the connections from my pump. It keeps the vibrations down.

Yup, seems to be a lot of advantages to vinyl for the return. I have never tried it myself, so I figure I may give it a shot.

[schroeder]

I know... it's an old thread, but I too am working on a plumbing system that uses flexible tubing, but not vinyl.

My plumbing will be on a 20 Litre Pico tank with 1/2" bulkheads.
Into the bulkhead fittings I am threading in a push fitting like the 'John Guest Speedfit'
http://www.johnguest.com/part_spec.asp?s=USNC23_S3

These fittings do have some stainless steel retaining 'teeth' in them, but the seal is formed by an O-ring that excludes all fluid from contacting the metal parts, and they are thus rated for semi-corrosive and/or corrosive liquids, but they cannot be immersed in saltwater because then the water will contact the metal 'teeth' that hold the tubing in place

These fittings can also be disassembled (ie: tubing removed) non destructively (difficult to do with barbs) so I can do away with unions, and no clamps are necessary

The tubing will be food grade 1/2" I.D. polyethylene

if you heat the polyethylene tubing in hot water it becomes more pliable and when it cools it retains some memory of the shape you bend it to so you can tidy up your plumbing. It is cheaper than vinyl (at least in quantity it is). Also vinyl is more prone to staining, or having VOC's or other compounds migrate through, but the poly is less permeable, and less reactive (just try and find a solvent cement for poly, nothing works well particularly on HDPE). One other advantage is that polyethlene has a lower coefficient of friction than the vinyl so the flow characteristics tend to be better, particularly if you can find the 'barrier' tubing.

I am nearly ready to start the plumbing. I just finished purchasing the last of the parts. I will try and post photos when I'm done.

BTW. GSP what did you end up doing for your plumbing?

[Myka]

Personally, I will use vinyl tubing for my drain lines, but not my return lines. I don't like to use them for anything with any pressure as I've had them pop before, even with clamps. I use them without clamps on the drain though.

[BlueAbyss]

Originally Posted by Myka

Personally, I will use vinyl tubing for my drain lines, but not my return lines. I don't like to use them for anything with any pressure as I've had them pop before, even with clamps. I use them without clamps on the drain though.

Hmm, this is something I hadn't considered. I wanted to have a section of flexible tubing on my 'return'... did the tubing pop, as in come off the barbs even with the hose clamps, or pop as in tear through the sidewall?

[Myka]

Came off the hose barb, clamp and all. Since the hose barb is plastic you can only get it "so" tight without cracking it, plus the walls of the 1" tubing are very thick. I had to heat the tubing in boiling water to even get it over the hose barb, and then clamped the crap outta it. I tried removing it once, and couldn't get it off without boiling water, and couldn't exactly get that in the right place!! I gave up, and the return pump blew it off for me! Not good. There was a lot of back pressure though because there was a ball valve holding back the return pump. There's no way the sidewall would tear. It's really thick.

[mike31154]

One thing to keep in mind with the clear vinyl is that any light source will promote 'growth' inside the line, requiring periodic cleaning. This is ok as long it's accessible, which in most situations should be the case. On the other hand, you 'can' see what's going on inside the vinyl tubing as opposed to pvc or other tubing, where it's a mystery until there's a problem.

[golf nut]

Also be very careful with math, a typical 3/4 barbed fitting doesn't have a 3/4 hole in it, I just measured one at.566 inside diameter that is a huge restriction when it comes to choking a 3/4 outlet pump. almost a 50% loss.

[NHRA]

When I built my system I used rigid 1' PVC and a very flexable and reenforced PVC. No hose clamps were required on the flexable PVC to nylon hose barb connections. This system has been running for a year and a half without even a drop leaked. The hose is a little expensive but I feel well worth it. It also has a bend radius of 3" for the 1" with no possibility of collapsing.

www.greenlinehose.com part#G941BW-100 for 1"

[banditpowdercoat]

Originally Posted by Mr OM

Also be very careful with math, a typical 3/4 barbed fitting doesn't have a 3/4 hole in it, I just measured one at.566 inside diameter that is a huge restriction when it comes to choking a 3/4 outlet pump. almost a 50% loss.

3/4" NPT ID, .755" 50% less .375 3/4" barbed fitting ID .566. It's more like 30% less, but who's counting HAHAHA