Tigahboy

Overflow Diagrams

240 posts in this topic

Just finished the 3 I'm most familiar w/ (i.e. have made/used for my own tanks).

 

hope it helps...

 

durso.jpg

 

 

extdurso.jpg

 

 

stockman.jpg

 

I'll try to do a breakdown of pros and cons of each overflow type as well. After I rest a lil tho. -_-

 

EDIT - I am adding a diagram for the Herbie overflow since wombat was so kind enough to contribute them to this thread.

 

Herbie Overflow

Diagrams courtesy of Matt Wandell (wombat)

 

Herbie1.jpg

 

Herbie1.jpg

 

You may add either a strainer at the top of the standpipes or an elbow. I've seen both. Some even add a durso for the higher (secondary) standpipe. But the main elements of a Herbie include a lower, primary standpipe with a gate valve to control the water level in the overflow box and a higher, secondary standpipe.

 

There are discussions about the Herbie throughout this thread, please do a search for them within this thread for more information.

Edited by Tigahboy

Share this post


Link to post
Share on other sites

I'll be following this one Tigah! Thanks!! :bowdown:

 

Rob

Edited by reef 'n ale

Share this post


Link to post
Share on other sites

*bookmarked* :ninja:

 

Thanks Tigah for the very useful information. Great diagrams.

Share this post


Link to post
Share on other sites
*bookmarked* :ninja:

 

Thanks Tigah for the very useful information. Great diagrams.

no problemo. just doin my "job." =) haha.

 

will post more info about each sometime next week.

 

and if y'all have any questions or diagrams need clarification, lmk.

Edited by Tigahboy
1 person likes this

Share this post


Link to post
Share on other sites

Tigahboy = Reef Pimp of the Southwestern World!!!

 

Thanks Dennis

 

Chris

Share this post


Link to post
Share on other sites

Your're the man Tigahboy.

Share this post


Link to post
Share on other sites

Thanks for the diagrams Tigahboy!

Share this post


Link to post
Share on other sites

Which one would you suggest, the durso, or the stockman, for an internal overflow?

 

Thanks for taking time to put the diagrams together.

Share this post


Link to post
Share on other sites
Which one would you suggest, the durso, or the stockman, for an internal overflow?

 

Thanks for taking time to put the diagrams together.

Stockman. I'll elaborate more when I do the pros and cons chart for each.

Share this post


Link to post
Share on other sites

Good thread. Might want to add in the links to the designers' sites too.

 

http://www.dursostandpipes.com/

 

(Stockman dfesign is also available on the durso site under "popular modifications")

1 person likes this

Share this post


Link to post
Share on other sites

good call.

 

but I'm not sure who designed the other 2.

Share this post


Link to post
Share on other sites

gawd! another thread for the lazy. lol

 

tigah, can you build me an award winning pico entry. :)

Share this post


Link to post
Share on other sites

thanks for this, Tigah. I have a question:

 

I recently bought a used Oceanic 40g from an LFS that was going out of business. It came pre-drilled with a 1" bulkhead w/strainer near the top right and a 1/2" return near the top left. Do you think

 

1) I should use the "external durso overflow" setup? Will this provide higher gph than just a regular drain (i.e. no durso)?

 

2) Will one 1/2" return provide enough flow for softies & LPS? I have no interest in keeping SPS. I think I may put a "Y" on the return with some locline attached.

Share this post


Link to post
Share on other sites

bump

Share this post


Link to post
Share on other sites

gawd. the return will generate a lot of pressure. what kind of flow do you want in the tank. for a target of 15-20x turnover, i would want at least 3/4. lots of pumps have 3/4 outs and easier to reduce the pressure.

Share this post


Link to post
Share on other sites

yeah, I think 15-20x turnover would be good. so are you saying you would try to increase the return size to 3/4"?

Share this post


Link to post
Share on other sites

3/4 will give you more pump options to get that kind of turnover. a stand pipe won't increase your flow. flow capacity is limited by the size and the depth of the hole(s) of the standpipe to the water level.

Share this post


Link to post
Share on other sites
thanks for this, Tigah. I have a question:

 

I recently bought a used Oceanic 40g from an LFS that was going out of business. It came pre-drilled with a 1" bulkhead w/strainer near the top right and a 1/2" return near the top left. Do you think

 

1) I should use the "external durso overflow" setup? Will this provide higher gph than just a regular drain (i.e. no durso)?

 

2) Will one 1/2" return provide enough flow for softies & LPS? I have no interest in keeping SPS. I think I may put a "Y" on the return with some locline attached.

 

External durso will not give you higher flow thru. But just a simple bulkhead at the back will be very noisy and the flow thru won't be constant (i.e. siphoning faster and slower).

 

two 1/2" returns would be more ideal.

Share this post


Link to post
Share on other sites
External durso will not give you higher flow thru. But just a simple bulkhead at the back will be very noisy and the flow thru won't be constant (i.e. siphoning faster and slower).

 

two 1/2" returns would be more ideal.

 

There's a post written by wetworx about flow rates depending not just the size, but the position in the back wall of the tank. Briefly, it says that the closer the hole to the top of the tank, the slower the flow rate will be. So yeah, it wont be as fast, but that doesn't mean that'll be turtle-speed flow rate. A part of the wetworx post as follows

 

Yep. The calculations I did come up with that figure, now keep in mind that my calculations are based on a vertical hole which technically wont drain as much as a horizontally mounted hole (simple example: a 1" hole at 1/2" depth mounted verticaly would only be half underwater yet a 1" horizontal/flat hole under even 1/4" water would be completely covered). So if you were to put a hole on the bottom side of a tank, as long as it is vertical, it will have slightly less pressure on it than a bulkhead mounted on the bottom glass because of it's height. So a bottom hole will have a slight flow gain on a side hole, but I am not going to redo my calculations because were talking a minimal gain here, considering we would be at 12" or more of depth the flow on a horizontal bulkhead is already in the hundreds. More flow can be lost with screens over the bulkheads and accumulation of crud on a bulkhead's intake, easily over 20%. That's why I would never go with a bulkhead less than 1" unless we are using it for less than 100gph, or you are sure to prefilter the water enough to prevent clogging (D, I think you will be fine as long as you put a sponge or screen in your overflow above the bulkhead to keep any chunks away).

Just short of graphing the chart with line curves I have for flow by cross referencing hole diameter with hole depth, I can post the following:

1"bulkhead @ 1" depth=338.6gph

1"bulkhead @ 1.5" depth= 414.8gph

1"bulkhead@ 2" depth=478gph

1"bulkhead@ 3" depth=586gph

1"bulkhead@ 4" depth=677gph

1"bulkhead@ 5" depth=757gph

...if you even need to know what the possible flow for a hole at a given depth is for more flow you dont have a nano anymore, and you are in the wrong forum.

3/4"bulkhead@ 1"depth=190.5gph

3/4"bulkhead@ 1.5"depth=233.3gph

3/4"bulkhead@ 2"depth=269gph

3/4"bulkhead@3"depth=329gph

3/4"bulkhead@4"depth=381gph

...you can draw the rest of the curve from there.

1.5"bulkhead, I dont think anyone needs these on a nano because 1" is enough for most tanks up to 40 gallons, and remember...a 1.5" bulkhead has more than double the intake area of a 1"...so were @ 933gph at just 1.5"deep.

 

Cheers :P

Share this post


Link to post
Share on other sites

thanks. I remember reading this a long time ago but I forgot about it

Share this post


Link to post
Share on other sites

How do you plan where to drill the holes for an external Durso setup? I've seen you do that in rbaby's tank and your 15s and was planning on emulating when my 33 arrives.

 

Chris

Share this post


Link to post
Share on other sites

it seems to me that the externa durso should have some sort of a downward facing elbow on it or something so that the ater always forms a sealwith the mouth of the overflow.

Share this post


Link to post
Share on other sites

If you use a strainer basket, like in the drawing, it will skim the surface. With the external durso, you don't have an internal overflow box to do that skimming, so you compromise.

Share this post


Link to post
Share on other sites

If your skimming then air is coming in and the hole in the top making the overflow a durso overflow doesnt do much does it. The hole keeps a full siphon from ever forming but that hapens when skimming too doesnt it.

Edited by Opcn

Share this post


Link to post
Share on other sites

My understanding is that the hole isn't a siphon break, it's purpose is to disrupt the vortices that form around oveflows. It's a shut the hell up hole, 'cause without it, the overflow will be very noisy.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now