Reef Central Online Community

Home Forum Here you can view your subscribed threads, work with private messages and edit your profile and preferences View New Posts View Today's Posts

Find other members Frequently Asked Questions Search Reefkeeping ...an online magazine for marine aquarists Support our sponsors and mention Reef Central

Go Back   Reef Central Online Community Archives > General Interest Forums > Do It Yourself

 
 
Thread Tools Search this Thread Display Modes
  #1  
Old 12/21/2006, 12:43 AM
a1rabbit a1rabbit is offline
Registered Member
 
Join Date: Apr 2004
Location: BC, Canada
Posts: 28
Reef Central's Drain Size Calculator

http://reefcentral.com/calc/drain.php

Is this the max GPH from syphoning or pure gravity?

What I mean by pure gravity is if the drain pipe (let's say 1") was attached to the tank so it was perfectly horrizontal and then had a 90 degree bend down to another tank. Could it handle 600gph?


Sorry if this is obvious to you, but I've been wondering.

Thanks.
  #2  
Old 12/21/2006, 08:04 AM
BeanAnimal BeanAnimal is offline
Premium Member
 
Join Date: Feb 2003
Location: Pittsburgh
Posts: 11,710
When you look at a flow model... any fully submerged drain IS in effect a siphon. When a drain is submerged, the TOTAL head on the system is what dictates the flow. The total head is the difference in level between the TOPS of both bodies of liquid + the friction of the plumbing.

If the drain IS NOT submerged and air is allowed into the system, then the open channel flow model is what is used to determine max flow. A siphon will always outperform open channel flow given the same size pipe and same head DISTANCE. I am not sure if I worded the well...

To answer your question... I THINK (not sure) that the RC calc is based on open channel flow.

Bean
  #3  
Old 12/21/2006, 07:05 PM
a1rabbit a1rabbit is offline
Registered Member
 
Join Date: Apr 2004
Location: BC, Canada
Posts: 28
Quote:
Originally posted by BeanAnimal
When you look at a flow model... any fully submerged drain IS in effect a siphon. When a drain is submerged, the TOTAL head on the system is what dictates the flow. The total head is the difference in level between the TOPS of both bodies of liquid + the friction of the plumbing.

If the drain IS NOT submerged and air is allowed into the system, then the open channel flow model is what is used to determine max flow. A siphon will always outperform open channel flow given the same size pipe and same head DISTANCE. I am not sure if I worded the well...

To answer your question... I THINK (not sure) that the RC calc is based on open channel flow.

Bean
Yes, I think I understand.

So basically, the calculator (as far as you know) is the open flow type of overflow/drain which means that if the drain is not fully submerged then a 1" drain will allow about 600gph through. If this same drain were fully submerged in water and created a siphon then it would perform even better than 600gph.

So for example, a 1" drain could easily accommodate 160-300gph powerhead/pump without flooding your house, even if a true siphon (fully submerged drain) was not created.

I may be completely wrong. lol

(this next part is basically me rambling to myself, just easier to type it out and read it over. Maybe others will want to see this someday)

So now I'm wondering, how do you make sure your drain does not out compete your pump and your pump does not out compete your drain? If you have a drain capable of 600gph and a pump doing 300gph you can't have a continuous siphon, can you? You can't replenish the water in the display fast enough... But on the other hand if your pump is 900gph and the drain is 600gph, well then you have a flood... Assuming the siphon created does not manage to keep it in check or you don't tone down your pump. I guess that's what the ball valves are for.

Soooo... I guess you'd rather have a 600gph drain with a pump capable of less than that with enough space at the top of your fuge/sump to accommodate the extra water that may flow out of the display if it over drains. Then the pump will catch up and the flow will start again...

Hmm, starting to understand a bit more now I think, even after reading lots of posts about it. Do I seem to be on track or am I way off?
  #4  
Old 12/21/2006, 07:26 PM
douggiestyle douggiestyle is offline
www.kandnsales.net
 
Join Date: Nov 2004
Location: MOON
Posts: 1,736
Send a message via AIM to douggiestyle
with a stand pipe. as what was said it is most likey an "open Flow" model anything else would require to many other variables.

but yes the drain should be larger than the pump. the drain will only drain what the pump pumps. you could have a drain pipe large enough to handle 10,000 gph. if the pump is only 300 gph then that is all that will flow down the drain.

does that help you?
  #5  
Old 12/21/2006, 07:37 PM
douggiestyle douggiestyle is offline
www.kandnsales.net
 
Join Date: Nov 2004
Location: MOON
Posts: 1,736
Send a message via AIM to douggiestyle
sorry i need to add more.

1. this is most important. nothing should ever flood.

you need to design your tank and sump so that they do not flood. make the sump larger, make the pump area of the sump smaller. if the power goes off the sump should be able to hold all the excess water that comes down the drain. if the drain clogs the aquarium should be able to hold eveything the pump pumps.

2. dont use ball valves to cotroll the flow. youl adjust one for the pump then the drain then the pump again. eventually you be using half the pumps output and half the drains max. if you need to controll anything controll your pump output; either buy a smaller pump or use a three way valve/design that spills the excess back into the spump.
 

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -5. The time now is 02:12 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Use of this web site is subject to the terms and conditions described in the user agreement.
Reef Central Reef Central, LLC. Copyright 1999-2009