Custom Tank
 

Hey guys. So I'm getting a tank built and Im submitting the order tomorrow. Its nothing crazy. Just the sizing and overflows/returns are all things I can customize and so I thought I'd quickly ask if anyone has anything I should know before I submit the order.

Basically Im getting a tank that will be 72Lx24Tx22W because that is how big my stand is. So essentially 165G. I'll be getting two overflows. The drains off these will be 1.5" and I know my returns will be 1" as well.

What linear distance should the overflows be? I'm thinking dual 10 inch ones. Also, where should I plumb the returns? I was thinking just into the back of the glass, as high up as possible, I'd get them to drill holes between the two overflows. Or should I do it through the overflows?

Thanks guys, any other suggestions are welcome.

I say go coast to coast. I did and I LOVE it. Only been a month, But C2C with Herbie style drain. Awesome!!!

but, what are you planing for sump flow? that really determines the minimum overflow weir length

i say make the overflows big enough to have the returns inside them also

Hmmmm I dont think I can do coast to coast but i not really sure. We'll see what the extra cost is. How are the returns plumbed if they come back up through the overflow? Do they hang over the back after coming up? Or are they plumbed in through holes cut in the back glass? Im going to get this thing ordered in about an hour so lets hear some more ideas. Cheers!

My C2C is plumbed through the back. And tghe overflow is just a piece of glass, 7" wide, siliconed at a V on the back. Heres a pic

http://banditpowdercoat.com/Powderga...%20%282%29.jpg

http://banditpowdercoat.com/Powderga...282%29%7E0.jpg

http://banditpowdercoat.com/Powderga...282%29%7E0.jpg

Ahhhh I see. Pretty cool set up.

I talked to the guy and this is a wholesale shop that basically supplies all the aquarium stores in the city with their tanks and we had a 20 minute conversation about what I wanted to do and we ended up settling on an 18" overflow box centered on the back with two seperate 2" drains. I'll likely only be using one with my current setup but he said he'd drill the other for free and that the tank could essentially be setup and plumbed to turn over the tank 30x an hour through this drain and the return holes which will be 1/2" holes cut evenly along the back as high as he can drill them and evenly spaced.

It'd be cool to get a pump that did 30x165=4950gph and have absolutely zero hardware in the tank. It'd all be in the sump, I wouldnt even need powerheads in the tank. I could just get those bendable spray arms for the returns and direct them wherever Id like.

I don't think you'd want 30x through your sump. The water would be going to fast for the skimmer to do a proper job, and you might end up with a micro bubble problem. You should be aiming for maybe 5-8x through the sump. Thats why you see people investing so much money in the powerheads(tunze's and vortech's) as well as closed loops is because the flow you want, which could be upwards of 80x's per hour needs to be within the display and not from your return pump. HTH

Run a closed loop off your overflow for most of your flow, and have a second pump for your sump return.

To high sump flow will lead to microbubbles. But won't affect the skimmer. Not all the sump flow flows through the skimmer.

besides, 1200GPH is about tops for 18" of overflow

It's 18" that dips 2.5" down. Pretty sure it can handle way more than that. The guy said the tank could turn over the water 30x with this setup if needed. Thanks for the thoughts on this guys, Im not really sure what Im going to do in terms of plumbing yet. I just made sure the tank was built in a way that I could basically do whatever I wanted with it.

Right now Im planning on running my sump at about 1200-1400 GPH (depending on how much head loss I get from my 1600 GPH pump) through the sump and then likely buy koralias for the rest of my flow needs. (the tank is 165G as a reminder) If, down the road, I do want to get rid of the koralias I could run a closed loop off of an exterior pump and use the return holes for my flow and have no hardware in the tank. That could be pretty cool.

Ya I've seen this. It'd be nice to know how high the water "overflows" into the overflow box when they calculate the drainage on that. Cause Im sure a 2.5"x18" constant waterfall is a hell of a lot more than 1200 GPH...

Lets do some math. A 2" drain has a 2500 GPH flow rate according to this site:
http://www.diamondbitsusa.com/index....d=48&Itemid=60

Now, this has a linear surface area of 3.14" (1 squared x pi)

My overflow has a linear surface area of 45" (18"x2.5")...

So I have two 2" drains, so 5000 GPH. Now assuming the drainage through the overflow is the same as through the drain (gravity might help) my overflow technically could handle 35,828 GPH before itd start to overflow the edges of my tank...

This dude has been building tanks for 30 years. He quoted what 1/2" bulkheads and 2" bulkheads are rated at for maximum flow off the top of his head. He had a tank with a 3 foot grand cayman alligator in it in the lobby of his shop.... I'm sure he knows what he's doing.

Lets just say the limiting factor on my drainage is my bulkheads, not my overflow cut out.

Your weir height will be 2.5" below the water height? You only want 1/4" or so of Skimming, the top surface of the water. Thats the whole reason for a overflow. the thinner the "skim" you can take off the top, the better. thats why I went with a Coast to Coast. Using All avail distance for skimming

And you can not take Linear surface and use it like Pipe area. Doesnt work that way.

Alright, so I got them to increase the linear size of the overflow to 22" linear now, so that should be pretty good to do 8x the empty tank volume per hour. That's not a bad amount and I'm sure the overflow can handle more if I need it to.