Need Help With Plumbing and Overflow Questions

[gemini]

Hello,
I am planning the plumbing part of my 40g breeder tank and have tons of questions!

I am planning on doing a coast to coast overflow (c2c) with a PVC pipe going most of the length of the tank with a slit cut on top for surface skimming.
(like this http://reefcentral.com/forums/showth...l+pvc+overflow )
I wanted to know if anyone has done a Horizontal PVC overflow like that, and how you liked it. Also, I am wondering some of the technical aspects of it. For instance, with 2 1" bulkheads draining into the sump, with one attached to each side of the overflow, how much can I expect it to handle? Should I leave the drains going into the sump separate, so there is more drain capabilities. I am not planning on running much flow through the sump; maybe about 200-300 gph.

would keeping them separate help the drain in case one end gets clogged somehow, or would it have ANY beneficial effect? otherwise I will just put the two drains into one pipe going into the sump. (am I making sense?)

Next aspect would be, how low do I have to drill the holes for there to be room for the PVC parts to successfully reach the top, without going out of the water. I am thinking I want the holes as close to the top of the tank as possible without the horizontal PVC reaching too far out of the water.

Thanks, I will update the thread if I think of any other questions.

Any help would be appreciated,
Xavier

[theicecreamdan]

I don't know if its better or worse, but I would keep them separate

[gemini]

Okay, thanks

[getem619]

I would keep them apart if one gets clogged you always have the other

[SoCalBoo]

Larrym (waves in glass) was building a large coast to coast for a customer when I was up at his place two weeks ago.

For flow rates, check out tests done by guys at glass-holes.com. Basically, for 1", you are looking at 300gph or so standard, up to 600gph at full siphon. For a 40g that you are looking to push 200g through, you should be fine. But I would make sure you do three drains if you can - google bean animal drain if you are not familiar.

For top skimming, it it hard to beat a coast to coast at 3-5x flow rate through sump - your are skimming about the thinnest top layer that you can.

Keep each drain separate! Putting 3 drain lines in is easy and the double redundancy is the best way to go.