Plumbing up my new tank, a few plumbing and overflow questions

[adamRS80]

I'm setting up a 40 gallon SPS tank. I'm using a Mag 7 and I'm expecting it to be running about 400-475 gph. It will be returning about 4' high through a check valve, and two Innovative Marine "Spin Steam" returns I was planning on using a single 1" bulkhead with a Durso overflow. Now I'm wondering if I should use a 1.5" bulkhead instead. My overflow is in the corner of the tank and is a total of 10" of weir. I'm planning on cutting 3/16" deep 1"4 wide overflow teeth but was considering a smooth overflow with no teeth. I think for surface skimming a smooth overflow would be optimal but I've read that it also makes it easier for fish to get sucked over, along with food and other stuff.

Will I be fine with a 1" bulkhead or should I use a 1.5" instead? Is anybody else running an overflow without teeth?

[FireWater]

RayAllen is running a toothless overflow.
What size is the hole for the return? If you have to back down to 1" for the bulkhead then going 1 1/2" won't do any good.

[adamRS80]

I have not cut any holes in my tank or sump yet. My returns were going to be two 1/2" bulkheads, one each running the IM Spin Stream. Originally I was going to run a 1" overflow from the tank to the sump. I started thinking that one 1" drain line might not be enough so I could run a 1.5" Durso standpipe, through a 1.5" bulkhead and bush down to 1" at the sump bulkhead. I became concerned because I figured it would not be a siphon and maybe 1" would not be enough. If 1" seems adequate than I'm all for sticking with 1" because I already have all the bulkheads.

[Cammed_02]

a true weir overflow has no teeth. I'm running one but you're right about fish taking a ride into the overflow. I just had a small clown take the plunge. luckily he didn't take the full ride down the overflow pipes.

[Diesel]

1'' is more than enough, with a 4' drop and use all 1" pipe to the sump you should have a about 1800 gallons running to your sump.
If you use a MAG 7 you might put a gate valve between to slow your drain down for a bit.
As of returns I would use not smaller tha 3/4 pipe, in that case you got max return from your pump.
What do you do for overflow?
As for a skim, it doesn't really matter on this size tank, just what you like the best.
Ofcourse with teeth can be a life saver for small fish.
That my $0.02 for today.

[adamRS80]

I was under the impression that a 1" bulkhead could not flow more than 600 gph except in a siphon situation. The overflow is just built into the corner of the tank, a 5"x5" box. I'll probably go with teeth on the overflow because with a tank this small, most of my fish will be pretty small too.

My skimmer is an AquaC urchin

[adamRS80]

After reading this page, I think I've decided to stick with the 1" bulkhead.

http://www.dursostandpipes.com/make-your-own-diy

[BBQHILLBILLY]

For a 40 and sump, 1in should be fine. Although I like the 1.5in for more flow on 75s. It also depends on the sump/refug setup. How much flow through your sump/refug?
And use teeth on overflow. The teeth will save your fish. I dont know why people use this toothless overflow.

[adamRS80]

The reason for the toothless overflow is that you should get better surface skimming over a toothed overflow. I don't really think the benefit outweighs the hassle of dealing with fish going over the edge though.

I've found a few 1.25" bulkheads. I'll use those to be on the safe side. Thanks fellas for the advice.