Quick Plumbing Q

[alexwolf]

For you water flow gurus......

I am coming into my tank through a 1" bulkhead. My pump outlet is 1 1/2". Does it make a difference if I scale it down at the pump or closer to the tank? IE, if I reduce it at the pump or the tank bulkhead?

[obtusewit]

The larger diameter pipe will have less frictional loss, but if we are talking about 6' of pipe, there will probably not be much difference if you reduce at the pump or at the outlet...

[verynewatthis]

well im new at this but this is something to think about...if you leave the pipe thick, and you are pumping up from a sump, you are fighting more gravity. This may slow your gph down. You are limited to the width of the pipe by your bulkhead so I would use that size for the whole pipe. The change over fitting would also be out of sight if it is in your sump, making a cleaner set up. Take this with a grain of salt because I am very, very new at this....
rich hancock 8)

[RobertG]

Alex, do not downsize from the pump. Use the same output of the pump until you must change it. This will keep your volume high without making more or losing any pressure. Where you downsize it you will increase the pressure out.

At the tank, not the pump.

HTH

[captexas]

I second Robert's input on reducing the pipe at the tank rather than at the pump. I also think having a reduction immediately at the pump might cause extra wear on the pump do to the increased back pressure.

[verynewatthis]

im sorry i guess i was wrong.....like i said im new at this.....i was just letting ya know what i thought....dont hate me....sorry...........
rich hancock

[TroyPham]

i'm gonna jack this post for a quick question. how long after glueing/bonding pvc do u wait before plumming it or using it in your system. i put together a check valve on sunday and haven't put it on the sytem yet cuz it still smells of the bonding agent.

ok. sorry. back on topic now

[NaCl_H2O]

Alex, I agree with those above - reduce the Dia as late in the pipe as possible. For the reasons above, but also ... if you ever add another outlet to your pipe run, you will have the capacity/presure in the larger dia pipe to do so.

TroyPham - I wait about 1.2 seconds after glueing PVC before using it! The only exception is a high pressure instalation, which there are none of in an aquarium system.

[AlexKilpatrick]

I have actually used it within minutes of bonding, and had no ill effects. I have heard of others doing the same. I'm not sure I would recommend that, though. It was an emergency in my case.

I'm surprised you smell anything this far after bonding. Are you sticking your nose right on it? I would expect that overnight would be plenty, even to be conservative. The stuff cures pretty much instantly.

[dan]

i would think back pressure is back pressure no matter where you are with the decress in pipe. once you turn the pump on and it hits that smaller dia. pipe you have back pressure from than on, on the pump no matter where you reduced it at.

... if you ever add another outlet to your pipe run, you will have the capacity/presure in the larger dia pipe to do so.
now this is true. SOOO i would do it at the tank

[jroescher]

Here is a short article that answers your question about where to reduce the pipe size:
http://www.dolphinpumps.com/plumbing.htm.

I don't remember where, but somewhere else I read that it's best to increase the size of the pipe by 1 size at the outlet, then reduce it back again at the last point you can.

[jroescher]

And yet another article from a very scientific view:
http://www.advancedaquarist.com/issues/jan2003/featurejp.htm
It's based on aquarium plumbing.

[TroyPham]

yea, i'm putting my nose up to it. but i let the pvc sit in water over night and the water smelled like the glue. is there a special glue being used. i just got the stuff from home depot. it's been since sunday and i can still smell the glue.

thanks

[alexwolf]

thts too long, shouldnt smell by now. I believe, depending on the glue, that it needs to cure dry.

[AlexKilpatrick]

yea, i'm putting my nose up to it. but i let the pvc sit in water over night and the water smelled like the glue. is there a special glue being used. i just got the stuff from home depot. it's been since sunday and i can still smell the glue.

thanks

Are you using regular PVC cement? The most common stuff is purple, and about the consistency of water. Typically, the top has a brush on it, and you just brush it on the joint before fitting it together.

I'm wondering if you are using something different.

Or maybe you actually have a dog nose. :)

[TroyPham]

haha.... no it's the stuff your talk'n about Alex. the primer is purple and the glue is umm snot like consistancey. i'm gonna put the check valve in place today. hopefuly it's ok.

thanks for the help