What Configuration For 40gal Breeder Overflow and Return?

[Enigma]

There is the general (sloppy) plan. I don't have exact measurements for the tank, as I'm at work and it isn't.

I think I need to change the height of the returns. I think it would be best if they were completely above the overflow, to prevent back-siphon. Yes? No?

[gregzz4]

That overflow is definately easier than making your own. I personally don't like it though as you're not giving yourself and emerg drain. Having a Herbie or Bean Animal would be much safer. You only need make your own overflow box with glass and skin it with acrylic. Make the box outside the tank, take it into a shop and have them fab the skin for ya.

Using my Chaeto tank build as an example of glass breakage is not the best as the glass was only 2mm to start with. The glass on your 40 will be a min of 5mm. With that said, I still agree with using flexible lines. Spa Flex is great for removing vibrations but is still kinda ridgid. Vinyl hardens over time, needs to be cleaned out if you don't block light and, of course, you have hose clamps to deal with.

This is also personal preference. I bailed on flare nozzles last year and started using round nozzles. Sure you don't get the spread of the 'fan', but you also don't have to mess with twisting them exactly where you want them.

Lastly, having your returns in that drawing location will limit your ability to point them into the back corners. If you've never used the Ys before, go buy them before you make your final decision. You'll see what I mean.
It's your build but what I meant yesterday is to have the returns right beside the box. This way you have more room to point one into the corner. Even better yet would be to have the returns coming out of the box sides. This would allow you to take the Ys out if you don't like having 4 nozzles.
I'll try to find you some pics.

[gregzz4]

I know, having the returns inside the box means a larger box. The advantage is more surface skimming and less water column draining.

I'm not having any luck right now finding a pic to demonstrate the flexibility of having the lines on the box sides.
What I'm getting at though is you have the back nozzles pointing to the corners across the surface and the others can be pointed more forwards, and down-ish if you like. It gives you more flexibility to find those flow sweet spots.

Back flow is definately something to consider.
I opted for over-the-top return lines to solve this issue
Because my overflow is offset, I have one nozzle left and a Y for 2 nozzles on the right.

[Enigma]

Very cool!

Thanks for posting the photos, Greg I'll show them to hubby.

[Enigma]

Well . . . Hubby would like to use the overflow setup that I linked too.

I do have an idea for a safety net that should work quite well for the setup . . . basically, my little sump will go inside a much larger container (another aquarium or a rubbermade, or something). As long as the returns are positioned properly it should be a sufficient solution: at least it would give the back-siphoned water a place to go.

I do really like the non-drilled returns in that photo. I think we'll try that and see how it works. If I don't like the way it works we can drill the returns instead.

[Enigma]

Hmm. Struggling with pump selection.

I'm leaning towards the Mag-Drive 950, as I don't think the Mag-Drive 700 will have quite enough oomph. Nothing that I've tried in the link provided by Greg seems to be anywhere near the right flow for my liking. The 700 will wind up under 400gph, and the 950 will wind up closer to 600gph.

Now, I can use the ball valves on the return system (there will be three of them) to decrease the flow into the tank . . . right? Can this harm the pump?

[gregzz4]

As for valving;
If you're talking about restricting the drain pipes with valves, ya there's no harm. This is how you balance your overflow.
If you mean restricting the return side of the pump, some pumps won't last as long with restricted back-pressure.
My overflow can't quite handle my return pump ( drain design issues ), so my main drain gate valve was a waste of money
I installed a Tee with a ball valve to regulate my return flow. The Tee is after the pump, so there is no restriction at all
This is what mine looks like ( on the right )



For pumps;
Mag drives are somewhat noisy and create heat
Eheim pumps are great and you could probably get away with a 1250, but don't go buying one yet. It's listed in the Head Loss calculator, but ...
Post your estimated plumbing info and hopefully someone with a similar experience will help steer you in the right direction. I don't want to be the only one recommending it
For a 40g breeder, IMO, 400g/hr is lots
Others may say different, but I'm targeting just over 600g/hr for my 75g

The total flow requirement for you tank is a combination of internal flow and return flow.
The return flow needs to be low enough that your skimmer can do it's job.

Hopefully others will chime in with exact #s for you