What Configuration For 40gal Breeder Overflow and Return?

[Enigma]

Hmm. I'm thinking this is the overflow:
http://glass-holes.com/700-gph-Overf...t-gh700kit.htm

Based on the overflow calculator, this one should be guaranteed for around 400 gph (despite the fact that it claims 700 gph).

400 gph should be, as far as I'm concerned, the appropriate flow rate for a 40 gallon. I don't want water screaming through the sump. I'm presently running two reactors (ROWAphos and Carbon), and I'll be adding a skimmer (when the system moves into the 40). I think the water should actually have the opportunity to be filtered before it goes back into the display.

If I go with that overflow, I'm thinking that two 1/2" locline returns (each with a "Y" splitter, for a total of four return nozzles) would be appropriate. These would both be fed off of the same pump. The one I have might work, uses a 3/4 in line, and would not be able to pump enough to exceed the overflow's capacity.

I'm looking at that overflow, as Hubby is not overly skilled with plastics. He's more of a wood and wiring guy. Ideally, I would like a 9", but the glass-holes overflow boxes are only available in 6" (the link I posted) and 12".

I'm also thinking that instead of using PVC pipes, I'd like to use flexible tubing (after reading through your build thread, Greg, and seeing what happened to your little Chaeto tank). In the event we use tubing, and not pipe, if something is shifted a little it shouldn't result in any glass breakage. The sump is not a big one (Aqueon Proflex Model 3) and I could see myself messing with it's positing when I add/remove things from it.

[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?