Return kit

[wannabe29]

First, thanks for the quick shipping of my 700gph overflow kit....and for the candy.  My wife wasn't sure if it was safe to eat so, therefore, she didn't get any. Ha! 

Anyway...my question is this:  What size return kit should I get for this overflow and what size pump? (ok...that's really two questions).

My system is going to be this:

40 gallon breeder with the 700gph overflow.  That drains into a 29 gallon sump divided into a protein skimmer area, a deep sand bed area and a return water area.  Above the deep sand bed section there will be a 5 gallon refugium.  This 'fuge will be fed by a t-junction off of the return pump controlled by a ball valve to reduce the flow going to the 'fuge. 

So, again, what size return kit should I use?  I would like to use 2 returns.  Also, since I am diverting some of the return water to the the refugium, what size pump should I use?  Also, what size pipes do you recommend for the overflow and the returns (okay, that's three questions)? 

Thanks a lot,
Matt

[superbuzz]

I'd go with two 1/2" returns and a pump in the 700gph total range. If you split this roughly in thirds between your refugium and two returns you should be good.  Use 1 1/2" for the drain, and whatever the pump discharge size is (prolly 3/4") reduced to 1/2" for each return.
We stopped shipping poison candy weeks ago....

[The Gent]

Ignorant question here:

What is to stop the return from drawing water out of the display tank and into the sump during a power failure?  I have been warned against a check valve for the return.

[superbuzz]

a:placing the return high in the tank
b:a siphon break

[The Gent]

Again, forgive my ignorance.  A siphon break?  With an over the top return i was going to drill a small hole just below the waterline.  How do I do it with your return kit? 

LOL Power just flashed on and off as I type this...

I do not know how much overflow my sump will hold i guess is the root of all my questions...

[superbuzz]

it's best to test it while you're watching to make sure everythings ok.
a siphon break can be created by having the return plumbing go higher than the waterline, and dropping back down to the return.  A hole is drilled and tapped for a jaco http://www.airwaterice.com/product/WA-ME0404/Elbow-Male.html fitting.  A piece of icemaker tubing is put into the jaco fitting and is directed at the water surface, just above.  When the power goes out, this will break the siphon just like the hole you were going to drill, just more complicated.

[The Gent]

Got it thanks!

[superbuzz]

you should be able to find that fitting, or one similar, at home depot

[The Gent]

I feel like an idiot.  Having a little trouble wrapping my head around it.  I was just gonna run vinyl tubing with a ball valve along it back up to the return, been talked out of a check valve.  I guess I am a diagram kind of guy.   Can't quite get it without seeing it.  Seems like it woud of been easier to go with the over the top, but through the glass looks better.