acrylic or glass...that is the question...

[minibowmatt]

13$ isnt bad. I will have to check them out. I have been gluing frags to my back wall. I already have some gorgonians, gsp, and zoos attached.. Im gonna go for the mixed species back wall and let them compete for space.. we'll see who wins.

 

[surfn]

ok, so here's another question about the external overflow.

since it will be external, the water will only be spilling over one side. thus wont it need to be larger? granted, i'm not planning on putting anything larger than a mag 3 dialed down on the overflow...so it doesn't need to be that big.

exactly how big will the overflow need to be?

 

[minibowmatt]

when I designed mine, I used the weir calculator over at RC. I think it asks what GPH you want to sustain, and then will give you a number in linear inches... If your adding teeth like mine, you have to factor that in as well. I found a couple figures for calculating flow through the comb at RDO. I will try to find those links for you. Basically, mine is 11X1.25 with a comb made up of 3/8" teeth. I have the comb positioned to stop fish, but not covering the entire opening in case snails or something clog it, the water can just flow over it.
I used a 1" drain in the OF box, and I used a mag 7 return. With the mag 7 totally open, I have my 1.25" slot half full of cascading water. The level inside the box is maintained by a durso.

 

[twon8]

ok, so here's another question about the external overflow.

since it will be external, the water will only be spilling over one side. thus wont it need to be larger? granted, i'm not planning on putting anything larger than a mag 3 dialed down on the overflow...so it doesn't need to be that big.

exactly how big will the overflow need to be?

the longer the better, if it is external make it as big as youcan, as that will skim the water surface the best.

 

[minibowmatt]

thats a good point. I had a spot that collects a little surface scum. I had to position my CL to keep the flow moving the scum toward the OF.

 

[minibowmatt]

Ok.. I found the link on RDO where I learned how to design my OF slot with teeth. Sorry it took so long!
here is the excerpt taken from this thread: http://www.reefs.org/phpBB2/viewtopic.php?t=82133&highlight=

"The height would be determined by how much waterflow you want through it, but as a general rule; a square inch will flow ~150-200gph via gravity so a 7" slot x 1.25-1.5"h will be good for ~1000gph +/- with no problem. By the same token, a 1/2" slot x 1"h will flow ~80-100gph and a 1/4" slot x 1"h will flow 35-40gph. This is probably a little conservative but I'm the type that would rather not have the water at the eurobrace but would rather have 1/4-1/2" airspace between the water surface and bracing but you can always valve the pump back a little."