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Flex pvc or sch 40 or spa flex?

Tazmaniancowboy

Tazmaniancowboy

Officer Emeritus
Officer Emeritus
I'm starting to get a list together for plumbing supplies to set up my new reef ready tank. On my last tank I plumbed everything with flex PVC and barb fittings all the way from the tank to the basement sump. This time I am thinking about doing regular PVC pipe. I've seen many people use both methods so I'm not sure which is better over the other. Can you tell me some pros and cons on both methods and your opinions on anything to look out for or plan to do? Also, with the sump in the basement, I want to make the tank as quiet as I can make it being it is in our livingroom. Any tips on this? Is hard or flex PVC any louder than the other?

Any input is appreciated
Taz

PS, I can also get spaflex locally please include this in advantages and disadvantages if you have used it. Sound deadening?
 
D

DaveK

In general rigid PVC pipe will transmit vibrations more than flexible PVC pipe will. Because of this I do like to use flexible PVC pipe for at least a foot or two going into and coming out of pumps. I also like flexible PVC pipe when I can make a gradual bend to get to a fitting. It saves a lot cutting and fitting there.

However, flexible PVC pipe does have some disadvantages. Since flexible PVC pipe has a slight spiral to it, there is a lot more friction when using it. Also, it's a little more tricky to glue. You should use cement made for flexible PVC pipe. It's a slightly different formula, and it will hold better compared to normal cement.

Since you are setting up a basement sump, and you'll have a lot of flow loss just because you are pumping up to the next floor, I recommend you use rigid pipe where ever possible. Then use short lengths of flexible PVC pipe going to and from the pumps, and in places where you need a gradual bend or need to get around something.

Since you also want to keep the pumps as silent as possible, I recommend you mount them on a thick, soft piece of rubber. A mousepad can work well for this. Also, I recommend the use of true union ball valves at the pump's intake and output. This lets you remove the pump for cleaning and other service.
 
H

harryk

I used Spa flex PVC for all the plumbing on my 215 for the drains and returns. I used regular PVC cement and i have no issues. I would definately recommend it.

Harry
 
AqOb

AqOb

DaveK said:
However, flexible PVC pipe does have some disadvantages. Since flexible PVC pipe has a slight spiral to it, there is a lot more friction when using it. Also, it's a little more tricky to glue. You should use cement made for flexible PVC pipe. It's a slightly different formula, and it will hold better compared to normal cement.
Click to expand...
This is an interesting point. I have been trying to wrap my head around what dynamic loss the spiral would create, and cannot find any spa-flex friction loss charts. I can find many for rigid, but if you could point me to one I would appreciate it.
 
D

DaveK

Ironhorseiv said:
In a typical stand with sump/fuge below, is flexible PVC appropriate for intakes and returns?(assume tank is drilled) Also, I have seen web sites that advertise their PVC as "saltwater safe: http://www.savko.com/portal/flexibletubing.asp"]Savko Plastic Pipe & Fittings, Inc. [/URL]Is this just PR hype or are some brands saltwater safe and others not saltwater safe?
Click to expand...

I don't think that this is mostly hype but it is just letting people know it's OK to use. Savko also sells normal plumbing stuff, and a lot of that is not :sw safe". I've gotten PVC pipe and fittings from several sources, and not had an issue.
 
D

DaveK

AqOb said:
DaveK said:
However, flexible PVC pipe does have some disadvantages. Since flexible PVC pipe has a slight spiral to it, there is a lot more friction when using it. Also, it's a little more tricky to glue. You should use cement made for flexible PVC pipe. It's a slightly different formula, and it will hold better compared to normal cement.
Click to expand...
This is an interesting point. I have been trying to wrap my head around what dynamic loss the spiral would create, and cannot find any spa-flex friction loss charts. I can find many for rigid, but if you could point me to one I would appreciate it.
Click to expand...

As I seem to recall, without looking it up, and remember that I may be wrong, the friction loss from flexible PVC pipe is high, with a few feet of it, in a straight run is about equal to a 90 degree elbow.
 
J

jonathan.

Flex PVC also builds up algae and everything else much, much faster than rigid PVC. It needs to be cleaned once in a while.
 
D

DaveK

jonathan. said:
Flex PVC also builds up algae and everything else much, much faster than rigid PVC. It needs to be cleaned once in a while.
Click to expand...

Not to give you a hard time, but I fail to see how you are going to get any additional algae build up using flexible PVC pipe. It's the same color and doesn't transmit light just like the rigid stuff. With no light it's sure not going to get algae. I have seen it build up a bacteria film on the inside, but it's about the same as rigid PVC pipe. I've never had to clean the inside of either type of pipe, except where a return or something similar is in the water, and light can get down that first inch or so.
 
V

vangvace

DaveK said:
Not to give you a hard time, but I fail to see how you are going to get any additional algae build up using flexible PVC pipe. It's the same color and doesn't transmit light just like the rigid stuff. With no light it's sure not going to get algae. I have seen it build up a bacteria film on the inside, but it's about the same as rigid PVC pipe. I've never had to clean the inside of either type of pipe, except where a return or something similar is in the water, and light can get down that first inch or so.
Click to expand...
Oops I was thinking that flex pvc was the clear tube sold in rolls at home depot. :-[
 
C

chaoscat

You know, I keep thinking about dragging out my old college Fluid Dynamics book for review....the only problem with that is I'd have to pull out and review the old Calculus book first.

Remember when you actually had the time to study things like this?

Actually, the problem is I DONT remember. :-\
 
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