Need help with linear overflow size on DIY overflow, teeth, threshhold, etc.

llebcire · 01/23/2009, 01:29 PM

As the title says, I need some advice with my DIY overflow. Bear with me as I might ramble a bit but the points/questions will be there somewhere!

I'm starting a 72g bowfront build, All-Glass (Aqueon) non reef ready tank that I will have the rear glass drilled (I think only bottom and front are tempered).

Initially, I'll be running +/- 507 gph, Rio 2500 using Reef Central's Head Loss Calculator.

For that flow, using the RC Drain Flow Calculator, I'll need a drain @ 0.93" with a linear overflow @ 8".

I'm using something similar to what ibmgeek used in this thread

with 1-1/2" x 3" reducers

According to the calculation that I found, linear overflow size equals Pi (3.14285) x diameter.

So using all of this information, a 1" PVC drain would more than handle the flow, and this reducer (3.5" internal diameter) should meet the minimum linear overflow @ 10.99".

1st Question:
This fitting satisfies the minimum requirement, but what will happen when I notch it to become a toothed overflow? How would you calculate the loss from the teeth? Common sense would tell me that if I cut a 1/4" notch every 1/4", then I would effectively lose half my available overflow. This isn't my planned notching, but used for a simple example.

While this setup will handle my initial flow, I most certainly will increase the flow at a later date, probably closer to 800-900 gph. According to the calculator, I would need a drain @ 1.24" and a linear overflow @ 14" to handle 900 gph.

2nd Question:
Are these numbers theoretical and I do need to allow for a variance say 5%, and that if I'm looking @ 900 gph I need to build a drain that can handle 945 gph (5%)?

3rd Question:
If I instead drill 2 bulkheads now, I could get away with two 1" drains to handle the flow, but do I add the linear overflow size together? Would it be easier to just create 2 overflows now, each designed for 450-500 gph?

4th Question:
Would only providing these 2 overflows with 507 gph (combined) cause any noise problems initially?

Thanks for any help that I get and feel free to ask me questions if needed!

llebcire · 01/23/2009, 10:18 PM

Anyone?

I know there are reefers here that can help!

Thanks!

01/23/2009, 01:29 PM	#1
llebcire Registered Member Join Date: Nov 2003 Location: West Des Moines, Iowa Posts: 1,210	Need help with linear overflow size on DIY overflow, teeth, threshhold, etc. As the title says, I need some advice with my DIY overflow. Bear with me as I might ramble a bit but the points/questions will be there somewhere! I'm starting a 72g bowfront build, All-Glass (Aqueon) non reef ready tank that I will have the rear glass drilled (I think only bottom and front are tempered). Initially, I'll be running +/- 507 gph, Rio 2500 using Reef Central's Head Loss Calculator. For that flow, using the RC Drain Flow Calculator, I'll need a drain @ 0.93" with a linear overflow @ 8". I'm using something similar to what ibmgeek used in this thread with 1-1/2" x 3" reducers According to the calculation that I found, linear overflow size equals Pi (3.14285) x diameter. So using all of this information, a 1" PVC drain would more than handle the flow, and this reducer (3.5" internal diameter) should meet the minimum linear overflow @ 10.99". 1st Question: This fitting satisfies the minimum requirement, but what will happen when I notch it to become a toothed overflow? How would you calculate the loss from the teeth? Common sense would tell me that if I cut a 1/4" notch every 1/4", then I would effectively lose half my available overflow. This isn't my planned notching, but used for a simple example. While this setup will handle my initial flow, I most certainly will increase the flow at a later date, probably closer to 800-900 gph. According to the calculator, I would need a drain @ 1.24" and a linear overflow @ 14" to handle 900 gph. 2nd Question: Are these numbers theoretical and I do need to allow for a variance say 5%, and that if I'm looking @ 900 gph I need to build a drain that can handle 945 gph (5%)? 3rd Question: If I instead drill 2 bulkheads now, I could get away with two 1" drains to handle the flow, but do I add the linear overflow size together? Would it be easier to just create 2 overflows now, each designed for 450-500 gph? 4th Question: Would only providing these 2 overflows with 507 gph (combined) cause any noise problems initially? Thanks for any help that I get and feel free to ask me questions if needed!

01/23/2009, 10:18 PM	#2
llebcire Registered Member Join Date: Nov 2003 Location: West Des Moines, Iowa Posts: 1,210	Anyone? I know there are reefers here that can help! Thanks!