Overflow length?

RussR19146 · 08/26/2009, 05:56 AM

Hi,

I have a drilled 90g tank - dimensions are 48 x 18 x 24.

My overflow (drain) tube is 1" diameter and 13" long. If I calulate correctly this is approx 37 gallons of overflow into a 30 gallon sump.

That sounds like a problem to me. What percentage of the sump should i fill on overflow? How many gallons - 20?

I can add length to the overflow tube easy enough

Thanks

Lightsluvr · 08/26/2009, 05:59 AM

I'm having trouble visualizing what you are describing. Cam you post a picture or two?

LL

JTL · 08/26/2009, 06:43 AM

If you are saying that the top of the tube is 13" from the bottom of the tank leaving 11" of water above it, then yes that is a potential problem. The drain down with that configuration would be 41 gallons. However, what really matters is the level at which the overflow box (weir) is set. The water can only go as low as the top of the box. The amount of water that can drain to the sump is determined by volume of water between the top of the overflow box and where ever you keep the level in the tank. An inch of water in your tank is about 3.75 gallons. Maybe I didn't understand the issue.

loyalrogue · 08/26/2009, 06:52 AM

If I'm guessing correctly, you are saying that your drainpipe is extending up 13" from the bottom up into your display tank so you are afraid that on a power outage your water level will drain from 24" down to 13", is that right?

Isn't there an overflow guard (plastic wall with slots) that surrounds your drainpipe? This is supposed to keep the water level in your display tank at a constant level no matter how short your drainpipe is.

If you don't have one then build one out of acrylic.

Also, to minimize the sounds of the "waterfall" effect, extend the drainpipe so that the opening is closer (within 1-3") to the normal water level of the display, and look into making a Durso-style top for your drainpipe.
http://www.dursostandpipes.com/make-your-own-diy

Post back and give us a little clarification on your tank/drain setup and we'll be able to give you a better answer.

RussR19146 · 08/26/2009, 07:10 AM

yes i was saying the drainpipe is extending 13" from the bottom. But now i see what you mean about the overflow guard. So really in case of a power outage the only drainage will be the amount that is in the corner where the drain pipe is!

So I guess i dont need to worry about the length of the drain.

Thanks!

Quote:

Originally posted by loyalrogue
If I'm guessing correctly, you are saying that your drainpipe is extending up 13" from the bottom up into your display tank so you are afraid that on a power outage your water level will drain from 24" down to 13", is that right?

Isn't there an overflow guard (plastic wall with slots) that surrounds your drainpipe? This is supposed to keep the water level in your display tank at a constant level no matter how short your drainpipe is.

If you don't have one then build one out of acrylic.

Also, to minimize the sounds of the "waterfall" effect, extend the drainpipe so that the opening is closer (within 1-3") to the normal water level of the display, and look into making a Durso-style top for your drainpipe.
http://www.dursostandpipes.com/make-your-own-diy

Post back and give us a little clarification on your tank/drain setup and we'll be able to give you a better answer.

JTL · 08/26/2009, 08:02 AM

Correction to my post. I meant to say the drain back volume is the amount of water that is above your RETURN outlet not above the weir.

Lightsluvr · 08/26/2009, 03:33 PM

Quote:

Originally posted by RussR19146
yes i was saying the drainpipe is extending 13" from the bottom. But now i see what you mean about the overflow guard. So really in case of a power outage the only drainage will be the amount that is in the corner where the drain pipe is!

So I guess i dont need to worry about the length of the drain.

Thanks!

If you "drain pipe" is truly only 13" high in a 24" tall tank, you are going to get some real gurgling, splashing noise in your corner overflow. That's because the water will be falling from about 22" to 13" (the height of the drain).

Look at the link provided by loyalrogue. That is an excellent article on how to DIY a standpipe (the correct name for your drain). I use them on all the standpipes in my tanks...they cost less than $3 in PVC and fittings to make. Your standpipe should be high enough so that water only falls 3/4"-1" from the tank level into your overflow (thingie in the corner). That amount of fall will be barely audible...

Good luck with your tank.

LL

08/26/2009, 05:56 AM	#1
RussR19146 Registered Member Join Date: Apr 2009 Location: Philadelphia, PA Posts: 104	Overflow length? Hi, I have a drilled 90g tank - dimensions are 48 x 18 x 24. My overflow (drain) tube is 1" diameter and 13" long. If I calulate correctly this is approx 37 gallons of overflow into a 30 gallon sump. That sounds like a problem to me. What percentage of the sump should i fill on overflow? How many gallons - 20? I can add length to the overflow tube easy enough Thanks

08/26/2009, 05:59 AM	#2
Lightsluvr Tangaroa to 500 gallons Join Date: Jul 2007 Location: Edmond, OK Posts: 5,855	I'm having trouble visualizing what you are describing. Cam you post a picture or two? LL __________________ Click on my username and select "Lightsluvr's Home Page" for a recap of our build thread - AGE Hybrid Tank in a 500G system with dedicated fish room. (Takes a few minutes for photos to load) Leave a note if you stop by... Current Tank Info: 350G AGE Hybrid reef tank. 500G+ total water volume. Three sumps for filtration. Barracuda Gold return and Hammerhead Gold closed loop pumps. DIY T5 light system on rails. MP40W x3 to supplement closed loop. 130G Water management system.

08/26/2009, 06:43 AM	#3
JTL Registered Member Join Date: Jun 2003 Location: Venice Island, FL Posts: 2,532	If you are saying that the top of the tube is 13" from the bottom of the tank leaving 11" of water above it, then yes that is a potential problem. The drain down with that configuration would be 41 gallons. However, what really matters is the level at which the overflow box (weir) is set. The water can only go as low as the top of the box. The amount of water that can drain to the sump is determined by volume of water between the top of the overflow box and where ever you keep the level in the tank. An inch of water in your tank is about 3.75 gallons. Maybe I didn't understand the issue. __________________ John 100 gallon DT and 50 gallon sump with refugium. Reefbreeders Photon V2+.

08/26/2009, 08:02 AM	#6
JTL Registered Member Join Date: Jun 2003 Location: Venice Island, FL Posts: 2,532	Correction to my post. I meant to say the drain back volume is the amount of water that is above your RETURN outlet not above the weir. __________________ John 100 gallon DT and 50 gallon sump with refugium. Reefbreeders Photon V2+.

08/26/2009, 06:52 AM	#4
loyalrogue Registered Member Join Date: May 2006 Location: Orlando, Florida, USA Posts: 1,535	If I'm guessing correctly, you are saying that your drainpipe is extending up 13" from the bottom up into your display tank so you are afraid that on a power outage your water level will drain from 24" down to 13", is that right? Isn't there an overflow guard (plastic wall with slots) that surrounds your drainpipe? This is supposed to keep the water level in your display tank at a constant level no matter how short your drainpipe is. If you don't have one then build one out of acrylic. Also, to minimize the sounds of the "waterfall" effect, extend the drainpipe so that the opening is closer (within 1-3") to the normal water level of the display, and look into making a Durso-style top for your drainpipe. http://www.dursostandpipes.com/make-your-own-diy Post back and give us a little clarification on your tank/drain setup and we'll be able to give you a better answer.