Overflow Teeth Size

Harleyguy · #1 10/18/2004, 10:48 PM

I'm sure exactly where to post this thread, but because this question directly pertains to my 465 I put it here.

How do you determine the size/length of overflow teeth? My overflow will 34" long (it goes glass to glass) I will have 2 drains (I can have 4 if I need them). I will have a big skimmer, ca reactor, chiller, canister filters, UV light, sump, and refugium). I expect to flow around 5000 gallons threw my overflow. How long should the teeth be? And what kind of spacing?

pmrogers · #2 10/18/2004, 11:04 PM

When planning my Tenecor acrylic the manufacturer told me to expect 100gph per linear inch of overflow. That is using their standard overflow slotting configuration of 1.5" tall by about a quarter inch wide.

I wanted to keep my overflow dimensions to 24"x12" corner mounted, so I had them increase the height of the teeth to 2". The overflow now handles ~4000gph with a comfortable 1/3" to the top of the teeth.

If you really need 5000gph through the sump you'll want either 2.25" high teeth on standard spacing or to go with wider teeth.

Make sure your sump has a great settling area design to handle that much flow without micro bubbles. Our sump is 7' long, has 2 over-unders and several horizontal baffles between the drain and return intakes yet we're still plagued by micro bubbles.

Regards,

Harleyguy · #3 10/18/2004, 11:19 PM

Thanks for the info. As for the sump, I have an idea that Andy at MRC came up with that will give me the equivalent of a 12' long sump. We will see if it works...

Acrylics · #4 10/19/2004, 08:10 AM

The Tenecor formula sounds about right. At *max* flow, a 1" deep slot x 1/4" wide will flow about 40gph. I use 30gph as a nominal number. At 30gph per 1", this amounts to 90gph per lineal inch if spaced 1/2" on center and 1.5" deep. 30gph x 1.5 (slot depth) x 2 (slots per inch) = 90gph. But 100gph is fine too, as I said, this is a nominal number

pmrogers has it down

2.25" depth on 1/2" centers will yield right around 6000gph at *max* flow and roughly 4600-5000gph nominally.

James

curthendrix · #5 10/19/2004, 10:22 AM

Harley,

Hope you don't mind but I've been following your threads in my tank design. My overflow on a 400g will be down one side (34" also). How wide is your box going to be in order to handle that much flow?

Curt

VegasMike · #6 10/19/2004, 11:16 AM

If you ordered your tank from IA, just have Mitch tell you what it will handle. He doesn't cut overflow teeth. Your overflow will, more than likely, be glass with black acrylic siliconed to it with black eggcrate across the top. I have no complaints about the black eggcrate as it's very easy to clean and nothing has gone through it yet. Some don't like it though.

One thing about the overflows - how do plan to quiet them down. Andy at MRC told me about using a 2"x4" coupling, kind of like a bowl sitting on top of the drain tube and it has worked very well. I also lay a 2" striner in the bowl to help break up the flow pattern a bit and that has helped to quiet them down even more.

Mike

curthendrix · #7 10/19/2004, 11:26 AM

My first thought about the noise was to try to soundproof the fishroom from the living room as best as possible. With the tank being in another room, are you still anticipated a sound problem. In my current 155g, I have raised the water level in the overflow and cut an acrylic cap which lies on top of the overflow to muffle the noise. Would prefer to keep the overflows uncovered so will try Andy's ideas if noise is a problem in the living room. Do you have any experience in how much noise is present with an inwall tank in the viewing room?

VegasMike · #8 10/19/2004, 11:37 AM

Oh yea, I've got soem experience. If you want to see details of my setup, do a search under my username for a thread entitled "450 Progress".

Maybe someone can post the URL as I'm not really sure how to do that.

Much of the noise can be isloated to the fishroom, but hte gurgling tends to be slightly heard. Using Andy's coupling idea and the strainers, I have no gurgling and the loudest thing I have is the Iwaki 70 pump that I have for the skimmer. I am about to upgrade that to a Sequence pump which will be more powerful, quieter and less energy consuming than the Iwaki. The fishroom is much louder than the viewing room. I was actually very pleased with how quiet the viewing room ended up.