Need some overflow advice

[mcoomer]

I'm building a 180 gallon tank and I need to build an overflow in the corner. I'm trying to decide on doing it in acrylic or glass. I'm leaning towards acrylic because it's probably going to be a lot cheaper to do than glass will be but I'd prefer to do it in glass because it will be easier to keep it scraped clean.

If I build it with acrylic I will need two sheets of black. First, will 1/4" sheets be thick enough for 23 1/2" X 9" overflow or should I go with 1/2" sheets? 1/2" will run $62, 1/4" is $32. Same question for glass. Thick or thin? My mind is telling me that since both sides will be full of water there won't be much bowing becauest there won't be a big pressure differential. Is that right? Also, 23 1/2" will put the top of the overflow a bit more than a 1/4" from the top of the tank. For acrylic I'm not worried about that as I can simply cut my teeth deeper to allow for more water flow over the top. For glass I need to know how much of a gap to leave. I suppose I could cut it short and put an acrylic fence around the top. What do you think?

So, glass or acrylic? 1/2" or 1/4"? Height of glass if I go that route? Any and all advice is greatly appreciated.

Thank you,
Mike

[mrx66699]

Acrylic all the way. Not even a question, its so much easier to work with and forget the scratch myth nonsense. If you scratch it you can buff it clean without even draining any water and not even miss a beat. Glass the scratch will be permanent. 1/4 will be fine for 9" width and you are correct the pressure will not be a factor. All its going to do is act as a barrier between the DT and the overflow area. I built this out of 1/4" you can use this for reference its 94" in length.

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