Bending pvc rather than 90s. Does it improve flow?

[BZos106]

I’m getting ready to setup a new tank. I’m going to be putting all the filtration in the basement. Roughly 13’ of head pressure not including fittings. I know that each pvc 90 reduces flow rate creating more head pressure. So I was wondering if flow rate improves if I were to bend the pvc into a longer sweep that still creates a 90 but not as drastic. Anyone know ?

 

[Montiman]

I have not done this but in general my understanding is that it doesn't matter as much as you would think. BRS did a video compairing using a 90 vs 2 45s and found very little difference.

 

[Reefs and Geeks]

With the viscosity of water and normal flow rates, it makes little difference unless you have tons of 90s. In theory, yes it will provide some decrease in flow resistance, but is likely negligible.

For example, when I'm working with hydraulic fluids that are 50X+ more viscus than water I can expect maybe a fraction of a psi decrease in head pressure by changing out a couple of 90s to smooth bending pipe.

 

[Jon Fishman]

Wish this was brought up before I busted my butt on my plumbing

 

[JoshH]

With the viscosity of water and normal flow rates, it makes little difference unless you have tons of 90s. In theory, yes it will provide some decrease in flow resistance, but is likely negligible.

For example, when I'm working with hydraulic fluids that are 50X+ more viscus than water I can expect maybe a fraction of a psi decrease in head pressure by changing out a couple of 90s to smooth bending pipe.

Do you feel with longer horizontal runs the head height increases significantly? I'm about to plumb mine and haven't bought a pump yet. I will be using one sweeping curve more for aesthetics than actual performance and the rest will be 90s. I have roughly 10' of actual head height (Not including 3-4 90s) and another 15' of horizontal run. Should I focus my pump selection based on the 10' plus the 90s or add even more for the horizontal run?

 

[Jay Z]

I noticed no difference in head pressure with 90’s in line.

What I did notice was a dramatic drop from not matching pipe size to return output size.

I had my vectra hooked to 3/4 off the get go for my return size. Had it at max for flow.

When I redid it, I ran 1 1/4” up to the junction, used a pair of 3/4” reducers sending it to the 2 tanks.

Now I’m at half speed with more flow than my first set up.

 

[Jay Z]

If running 2 tanks up stairs off my vectra. 10’ of head on both, 20’ lineal run and 4 90’s on The other. Overflows have a hard time keeping up if I crank it all the way up. But the one tank has dual 3/4” overflows in it.

 

[Brew12]

Do you feel with longer horizontal runs the head height increases significantly? I'm about to plumb mine and haven't bought a pump yet. I will be using one sweeping curve more for aesthetics than actual performance and the rest will be 90s. I have roughly 10' of actual head height (Not including 3-4 90s) and another 15' of horizontal run. Should I focus my pump selection based on the 10' plus the 90s or add even more for the horizontal run?

The horizontal run will make less difference than the difficulty reading the pump curve accurately imo.

 

[MrWheelock]

I have not done this but in general my understanding is that it doesn't matter as much as you would think. BRS did a video compairing using a 90 vs 2 45s and found very little difference.

I was going to link the same video! Good stuff

 

[JoshH]

The horizontal run will make less difference than the difficulty reading the pump curve accurately imo.

Exactly what I wanted to hear, wasn't sure if I needed to size my pump based off just the 10-12' in overall height or the entire run of the pipe that's higher than the pump putting the HH in the 25' range which makes selecting a pump far more difficult.

Thanks @Brew12 !