Plumbing a new tank, rigid or spa-flex

[das75]

Agonizing on how I'm going to plumb and route for my CL with a 4-way plus a basement sump, finally drew it up and bought the pieces. Now I've got about 600 bucks in PVC (valves included) in front of me and thinking SPA-FLEX.

Because the tank is sitting on a pony wall with shelves, with rigid fittings I'm forced to use 3-90° just for one leg of the CL. If I used spa-flex I could probably get by either just the S-F or the S-F and one 45°.

Considering that S-F isn't smooth inside, would I be gaining anything in using S-F in 3 feet rather than 3-90° and rigid pipe?

 

[Anonymous]

It does help a little due to the lack of sharp 90 elbows, but you will need to deside if that will make any difference. For most pressure rated pump, it is no issue, but with your close loop, you may want to have least head if your pump is not pressure rated.

 

[smontanus]

With rigid pipe you can calculate the flow resistance of lengths of pipe and equivalent pipe length of fittings and then calculate required pressure. So you could be reasonably sure you were hitting your flow needs. With flex, like 7-e said there's less resistance in general with the turns but I have no idea how to calculate the flow characteristics of that stuff. I had a similar problem and went with rigid just so I could calculate and know the required pumphead. I haven't regretted it so far.

 

[FragMaster]

Calculate it the same way BUT use 45's instead of 90 degree angles.
Reef central has a nice little calculater for this.
I hate reef central in general but this tool is very usefull! LOL!!

 

[HisKid]

For my part, I always used rigid schedule 40 PVC. Its easy to work with and doesn't wear like flexible tubing.

I also agree with the others, only I would add that if you are attempting to pump over a long distance, schedule 40 is definately a better way to go.

What some people overlook is the fact that rigid PVC will garuntee the minimal loss of head pressure because all the energy of the pump is directed along the inside of the pipe at the water. Since flexible tubing is not smooth, there is a great deal of turbulance in the tubing. If the water is tumbling all the way, it will take more kinetic energy to push the water than a smooth lined pipe. This can be observed by looking at how much flexible tubing moves around (oscillates) during pumping.

My 2 cents...

 

[minibowmatt]

to piggy back on Das75's question, has anyone used PEX to plumb their tank? I would use it, but Im unsure of using the compression type fittings it needs. I have also considered this: http://www.usplastic.com/catalog/pr...e cheap too... and It looks pretty flexible.