Fundamental questions on plumbing and flow

edacsac · 10/09/2007, 10:28 AM

Overflow considerations:
If I use the calculator on this site I can come up with the proper bulkhead size and linear inches for the overflow.

1.) Is it ok to have more overflow surface than you have gph (in the case of planning for a future upgrade)? Like if the calculater says 7 inches and you overdo it with 10 linear inches?
2.) Does linear really mean linear, or can you add up the front and side of the overflow to create a linear measurement? Example: you need 8" overflow. Do you build and 8x4 over flow because you have 8 "linear inches", or can you build a 4x4?
3.) Is the recommeded linear inches the slots in the overflow, or the total overflow?
4.) I've been reading about overflows with no slots, but rather eggcrate over the top of the overflow at the water level height. I like this idea, but I don't understand how it fits in to the overflow calculations since there are not teeth.
5.) If the calculator recommends a 3/4" bulkhead, is it ok to use a 1" or 1 1/2" inch? What are the drawbacks other than noise (if not using a durso or some other noise reducing technology)?
6.) I know the height placement of the bulkhead also affects flow, but if you place the bulkhead much lower in the tank, will you drain the overflow faster creating more noise? If its too high, then your in big trouble because it won't keep up with the return pump? Best place to put the overflow bulkhead?
7.) Is it ok to use a strainer basket inside the tank for the closed loop intake?

This question is tough for me to explain. --> As far as general plumbing is concerned, how can I calculate flow or determine problems adhead of time if I reduce or expand plumbing diameter. Example: For my closed loop, I will most likely choose a pump that will have a 3/4" or 1" output. The closed loop will output will be plumbed into a manifold made of 1/2" pvc, with probably 4 outputs. What changes here going from 1" or 3/4" to 1/2", and how do I determine what the flow will be at each output? I imagine if I'm shooting for lets say 800gph in the CL I will need a pump that does better than 800gph, but how much?

thanks a bunch!

papagimp · 10/09/2007, 10:34 AM

In regards to the drain line sizes and oveflow sizes, you can always go bigger. The only downside I can think of would be potential gurgling noises from the drain, but theres ways around that.

As for the last question, see if this helps at all: I'm currently using a mag12 returtn on my 75g w/ 20g Long DIY sump. The outlet on the pump is 3/4" and ran to the top of the tank where it then reduces to a 1/2" pvc manifold with 4 outlets. The headloss is bad enough that I don't even need the second u-tube on my overflow, one would suffice, so my 1200gph pump is probably pushing closer to 600gph. I could have avoided alot of headloss by reducing the amount of 90 degree connectors and instead of the 1/2" , should have gone with 3/4" the entire way and just put reducing adapters on the outlets themselves. I will be redoing the manifold/return setup, but gonna have to wait until ai have a better reason to tear all the rock out of my tank (the manifold runs through a rock pillar, under the substrate, and out from each 4 corners. This added length in the return adds alot to headloss as well.

edacsac · 10/23/2007, 09:06 AM

Wow! You lost 1/2 of your gph going to the 1/2 manifold?? Wow!!

I was thinking of using 45's instead of 90's around my manifold, but then it wouldn't fit so nice. My manifold will be part of the closed loop, so my pump should be pretty close tot he manifold if I do it right. My tank is only 24 gallons so, 3/4" manifold would stick out a bit. So I'll need like a 2000gph pump?? Wow!

10/09/2007, 10:28 AM	#1
edacsac Registered Member Join Date: Jul 2007 Posts: 40	Fundamental questions on plumbing and flow Overflow considerations: If I use the calculator on this site I can come up with the proper bulkhead size and linear inches for the overflow. 1.) Is it ok to have more overflow surface than you have gph (in the case of planning for a future upgrade)? Like if the calculater says 7 inches and you overdo it with 10 linear inches? 2.) Does linear really mean linear, or can you add up the front and side of the overflow to create a linear measurement? Example: you need 8" overflow. Do you build and 8x4 over flow because you have 8 "linear inches", or can you build a 4x4? 3.) Is the recommeded linear inches the slots in the overflow, or the total overflow? 4.) I've been reading about overflows with no slots, but rather eggcrate over the top of the overflow at the water level height. I like this idea, but I don't understand how it fits in to the overflow calculations since there are not teeth. 5.) If the calculator recommends a 3/4" bulkhead, is it ok to use a 1" or 1 1/2" inch? What are the drawbacks other than noise (if not using a durso or some other noise reducing technology)? 6.) I know the height placement of the bulkhead also affects flow, but if you place the bulkhead much lower in the tank, will you drain the overflow faster creating more noise? If its too high, then your in big trouble because it won't keep up with the return pump? Best place to put the overflow bulkhead? 7.) Is it ok to use a strainer basket inside the tank for the closed loop intake? This question is tough for me to explain. --> As far as general plumbing is concerned, how can I calculate flow or determine problems adhead of time if I reduce or expand plumbing diameter. Example: For my closed loop, I will most likely choose a pump that will have a 3/4" or 1" output. The closed loop will output will be plumbed into a manifold made of 1/2" pvc, with probably 4 outputs. What changes here going from 1" or 3/4" to 1/2", and how do I determine what the flow will be at each output? I imagine if I'm shooting for lets say 800gph in the CL I will need a pump that does better than 800gph, but how much? thanks a bunch! Last edited by edacsac; 10/09/2007 at 10:38 AM.

10/09/2007, 10:34 AM	#2
papagimp COMAS Rocks! Join Date: Apr 2006 Location: Oklahoma City, OK Posts: 8,185 Blog Entries: 2	In regards to the drain line sizes and oveflow sizes, you can always go bigger. The only downside I can think of would be potential gurgling noises from the drain, but theres ways around that. As for the last question, see if this helps at all: I'm currently using a mag12 returtn on my 75g w/ 20g Long DIY sump. The outlet on the pump is 3/4" and ran to the top of the tank where it then reduces to a 1/2" pvc manifold with 4 outlets. The headloss is bad enough that I don't even need the second u-tube on my overflow, one would suffice, so my 1200gph pump is probably pushing closer to 600gph. I could have avoided alot of headloss by reducing the amount of 90 degree connectors and instead of the 1/2" , should have gone with 3/4" the entire way and just put reducing adapters on the outlets themselves. I will be redoing the manifold/return setup, but gonna have to wait until ai have a better reason to tear all the rock out of my tank (the manifold runs through a rock pillar, under the substrate, and out from each 4 corners. This added length in the return adds alot to headloss as well. __________________ 58g Softie & 75g Stoney Member, Central Oklahoma Marine Aquarium Society Current Tank Info: 58g Mixed Reef Project - Started June 2011

10/23/2007, 09:06 AM	#3
edacsac Registered Member Join Date: Jul 2007 Posts: 40	Wow! You lost 1/2 of your gph going to the 1/2 manifold?? Wow!! I was thinking of using 45's instead of 90's around my manifold, but then it wouldn't fit so nice. My manifold will be part of the closed loop, so my pump should be pretty close tot he manifold if I do it right. My tank is only 24 gallons so, 3/4" manifold would stick out a bit. So I'll need like a 2000gph pump?? Wow!