designing an internal overflow

Here is the situation. It's sort of a "room divider" deal.







I want to end up as clean and uncluttered as possible. I THINK that means a "top to bottom" internal overflow at the end of the tank touching the wall.

And I could plumb the return line up and out through the side of the overflow, too, right? Is that hard to do?

I'll need to figure out how much flow will be needed (I think maybe 300gph?), thereby what size pipe, thereby what size bulkhead, thereby what size holes to drill and how big the overflow itself needs to be. Thoughts?

Also, should I plan to build the overflow myself out of glass, or buy one somewhere?

I'll cut this short here, in case I'm going the wrong direction entirely, and see what the experts have to say!

 

How wide is the tank, could you go with an island overflow? Or maybe a corner overflow in the area that butts up against the wall?

 

It's a standard 29 gallon - 30 x 12 x 18.

We think alike. I thought about the island overflow first, but decided against it due to the 12" width. I feel it would just take up too much tank.

The corner was my next thought, but then it would cut out part of the long-side view from the kitchen.

With an overflow at the end, I might create a sort of peninsula look. Maybe.

 

I think you're on the right track. Most people put the return up and over the top of the overflow though there is no reason that I'm aware of that you couldn't put it through the overflow wall if you want. It would just require drilling another hole whereas going over the top you can just use locline which is pretty popular.
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300gph for the return pump is just fine (although that's just for the return you will probably want more flow from powerheads inside the tank for circulation).

As far as whether you want to do a corner or "coast to coast" overflow that's entirely up to your aesthetics and how much room you want to lose in the tank. The corner overflow is more space efficient but the coast to coast may be better aesthetically and may work for the peninsula aquascape better, that's really your decision. Just make sure you have enough room behind the overflow for all the plumbing and enough room to do a little work in there if you need to (siphoning out detritus etc.).

The size of the plumbing isn't really a big deal IMO as long as it can handle the maximum amount of flow. I just use 1" for everything, you can get away with 3/4" if you want for the amount of flow that's going through them though. Just get a bulkhead that's for the same size plumbing as you use. If you look here each bulkhead will tell you what size hole is required for it.
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As for building one I would personally go with black acrylic, for one thing with glass you will be able to see through until it gets encrusted with coralline and looking at the plumbing back there isn't necessarily the nicest view. Also you probably want slits cut in at the top which I don't think most people are equipped to do themselves, or you would have to add an acrylic top piece with the slits yourself in which case IMO you should just use acrylic the whole way.
You can have one built for you, this place built my overflow and it's nice and I think reasonably priced. You may have to email about the pricing for the coast to coast overflow though.
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One other thing I noticed, are you planning on covering up the back of that stand? Otherwise it might be a little loud for the person sitting in that chair with the pumps and waterflow going through the sump down there. You might want to look into the "herbie method" of overflow using a primary drain with a siphon and an emergency backup drain, since it's perfectly silent.

Hope that helps! I like the idea of the room divider peninsula!

 

Thanks Screwtape, you are a fountain of knowledge as always! Yes, yes, over the top for the return line would definitely be easier, what was I thinking of? It's amazing the simple stuff that gets by sometimes.

Yes, the back of the stand is definitely getting covered. I'm building doors for it right now. Hopefully I can make them match the rest of the stand pretty closely.

I only heard of the Herbie drain for the first time a few days ago. It sounds great (silent is good!!) and foolproof if done correctly. That's a good idea - I think I'll use it!

 

One more thing: about those teeth at the top of the overflow. How absolutely necessary are they, really? I know everybody has them because they keep snails out (ususally), but do I really care if snails get in the overflow?

The reason I ask is, if I didn't have to have teeth, I could construct the overflow out of black glass. Nothing against buying one, I just like to make stuff.

 

How many GPH are you looking to push through the sump? Checking the overflow calculator at RC, if you went with a 4" square center overflow you should be able to get over 700gph easy. A 4" box would give you at least 4" per side, if you shifted it off center of the tank it might look pretty sweet.

Otherwise a coast to coast overflow up against the wall would give you a sweet peninsula look. I'm sitting here looking at my 29g trying to get ideas

 

I'm THINKING that I would only need 300gph or so through the sump. I could do more if necessary, but keeping the overflow small is important to me, looks-wise.

 

3/4" is rated at 300something GPH but that is under ideal circumstance, 1" is going to be the way to go. Just make the overflow box the minimum size you can squeeze a durso in

 

I think the main reason to not have snails in the overflow is them clogging up your plumbing. The teeth could also catch other things to clog up the drain like maybe a fish that dies unexpectedly or a chunk of algae that tears free or something. The teeth are a great way of introducing a fault-tolerant overflow/surface skimming system.

I guess if you do end up going with the herbie method you will have an emergency drain so it won't mean a flood if your primary drain gets clogged but it will be a hassle to disassemble the plumbing and get it out at the very least. So it's a risk/reward thing, you get to decide if it's worth it!

One more thing just to clarify if you do go with the herbie you don't need a durso, a durso is only to quiet down non-siphon drain plumbing. This might save you some space if you decide to go with a corner overflow.

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