Overflow Options

[Forbesy]

I have a 150 gal with an overflow that has 4 holes drilled into the bottom.

2 x 3/4 inch
1 x 1 inch
1 x 1 1/2 inch

I'm planning a bean animal using the 1 1/2" for the full siphon 1" for the secondary and the 2 3/4" lines as the emergency.
Does this sound like a good idea?
The tank is an in wall setup so I'll be running my return lines up the back side of the tank separate from the overflow.
My return pump is a Reef Octo Varios6 @ approx 800-900 gph with head presure.
The 2 3/4" emergency lines should handle this in a worst case scenario? My research shows they should handle around 1300gph just from gravity alone.
I'm wondering if I may be missing something.

I'm new to this whole saltwater thing so I'm just looking for some feedback as I move forward with this build.

Thanks in advance.

 

[Reef AquaCult]

That sounds good to me. Sounds like plenty of safety built in

 

[Reef AquaCult]

Actually I think its better to use the inch drain as the primary full siphon drain. at 900 gph you might have issues with bubbles and difficulty getting a full siphon going in the 1.5 inch drain which can handle a massive amount of water. You can also consider using one of your 3/4" holes for the return line because a 3/4" return line can also handle this flow rate. Good luck

 

[Forbesy]

Thanks for the input.

 

[RocketEngineer]

Honestly, I would want to the largest drain to be the emergency so that if something goes wrong it can handle everything that can be thrown at it. While a 3/4 main drain seems small, I would rather be safe than sorry. 1-1/2" would be my emergency and the 1" would be the secondary drain. The last 3/4 would be the return.

 

[Forbesy]

Thanks. From everything I've been looking at your suggestion seems to be a winner. My return pump has a 1 1/4" return line. Would the head loss be insignificant reducing to a 3/4" line?
Thanks again.

 

[dugthefish]

1" main, 3/4" secondary, 1.5" emergency, 3/4" return

 

[JoshH]

Personally I would go with a Herbie drain setup, 1" for the main, 1 1/2" for the secondary/emergency drain and go with dual 3/4" returns. Going from 1 1/4" outlet on your return pump to 3/4" is seriously choking off your DC pump.