is my acrylic overflow box design perfect?

looks fine to me, however in the rear of the overflow box i heard putting an elbow rather than a straight drain will reduce slurping sounds

 

Your design looks similar to one I built a few years back, except I used a u-tube to move water over the edge of the tank. Also used an HGB style standpipe which was dead silent. I managed to dig up some old pics, which might give you a few ideas for your design:

DIY "Hofer Gurgle Buster" (HGB) style standpipe:


Note the nylon screw on the base is used to level the overflow against the outside tank glass:


I used a slot plus a nylon screw/wing nut for water level adjustment:


DIY PVC u-tube shown here:

 

i liked this u-tube also, so was planning to build both, thanks for the pics. mine is a 15 gal nano (15"cube), planning to add a sump. so want to make it. any ideas on the flowrate?

 

For a 15 gal, I would shoot for anywhere between 100 and 200 gph. You could plan for a bit higher than you want and use a ball valve on the return line to fine tune your flow.

 

ya thats a good idea.

 

hey are my dimensions correct? was planning going an inch less on the front and back as its looking pretty big in my tank when i measured.

 

Looks good to me. It might be worth taking a look at Glass-holes.com's overflows (even though they are drilled type) to get an idea of flow rates versus internal box dimensions. For example, the Super Nano con Dientes Overflow I use on my 34gal Solana is 5" wide X 4.5" tall w/ 1" teeth, and is rated at 300gph (I run around 200-250gph through it). You could probably look up the stats on other manufacturers overflows, such as Eshopps and CPR aquatics, as well.


Note: my DIY overflow above was capable of ~600gph and the design was based on one by Proclear Aquatics

 

new overflowbox dimensions

check out the pic