return size

[Ryan Kouns]

to start this will be my first reef tank.. so this maybe a dumb question

I was looking at the SC aquarium 120 gal drilled for the Synergy 16 overflow, they state that the return size is only 1/2.. isnt that to small for a 120 gal? I was talking to BRS and they said it should have 3/4 return but I have confirmed with SC aquarium is only 1/2

should I go a different route?

 

[AZRipp]

Typically your return size is driven by the pump's outlet size. However, if you go a little bigger, you can always use smaller fittings, you can't go bigger, unless you re-drill, which is usually impossible (or at least very difficult without grinding away with a diamond sanding drum). If you find you want a bigger return pump that requires a bigger port/bulkhead, you'll be glad you went bigger right up front.

 

[Hal3134]

+1 for "base it on your pump outlet size". FWIW, I put about 2000g per hour through my 1 inch return. It would be more except I have about 15 ft of head. Iwaki 100RLT pump.

Personally, I'd run a Herbie or Bean using the existing holes and run a return over the side if I didn't have enough holes in the overflow.

 

[Ryan Kouns]

@AZRipp @Hal3134 good to know, I will be using the COR20 it comes with 1 1/4 union but has adapters down to 3/4.. think ill be ok to adapt down to 1/2 since ill have a T going to dual 1/2 returns? I was going to use 1 inch all the way to the T then adapt down from there?

Can you give me some suggestions on what you guys think is best

 

[AZRipp]

Also keep in mind some of the more modern DC and similar pumps use larger inlets and outlets. I know my Red Dragon's are big. So if you wanna upgrade or find you need more flow, being able to just remove a reduction fitting on your bulkhead is very convenient.

 

[AZRipp]

If a pump is designed for a specific inlet/outlet size, stay with that. If you go smaller you are increasing head pressure which greatly impacts the pumps flow rate.

 

[BZOFIQ]

With current offerings of DC pumps I'd recommend 1-1/4 or 1-1/2.

Flow is severely affected when you reduce the output tube.

 

[Hal3134]

Yeppers, use a pipe size that matches your pump outlet. Don't restrict smaller than that.

Not that you asked, but technically you can size up your return pipe with an adapter (say 1 1/4 pump outlet to 1 1/2 inch pipe) as a larger diameter pipe reduces the frictional losses and you will gain a slight increase in pump output flow.

Make sure that your drain size and overflow linear dimension can handle your pump return flow, otherwise you will get a flood.

 

[Ryan Kouns]

im going to use 1 1/4 until I get to the T for it to split off to my returns. So at that T I would reduce down to 3/4 then right when it goes into the tank reduce down to 1/2. Do you all see that being a problem?

 

[Potatohead]

What SCA normally does is 1” return that splits into two 1/2” loc-lines. It does come with some soft tubing that will adapt to the vast majority of pumps.

 

[mfinn]

Since you really only need 3x to 5x the tank volume going through the sump a 1/2" return is plenty.
And if that is the size hole that is pre-drilled in your tank, I really don't see any need to start out with anything larger than 3/4" off the pump.
You are just going to have to reduce it down to the 1/2"

 

[Ryan Kouns]

Thanks to all of you for your feedback its appreciated

 

[Hal3134]

Since you really only need 3x to 5x the tank volume going through the sump a 1/2" return is plenty.
And if that is the size hole that is pre-drilled in your tank, I really don't see any need to start out with anything larger than 3/4" off the pump.
You are just going to have to reduce it down to the 1/2"

+1. Smaller diameter pipe is also easier to work with.