Help me with my overflow dimensions

[jlinzmaier]

I'm trying to Calculate the size of the overflow for my next build. I obviously need to make sure the overflow box is big enough and the drains are large enough. I went to the overflow calculator link on the home page and typed in 5400gph for flow (that's approx what my return will produce). It gave me a reading of drain pipe diameter to be 3.03 in. and a linear overflow size of 82 inches. I understand the pipe diameter and I think I have that covered because I was planning on two 3in drains.

The linear overflow size has me a bit puzzled. What exactly is that referring to??

My tank will be 96 in long, 36 in wide, and 28 inches deep. I'm planning to have an overflow at only one end. I thought the overflow would be approx 32 in across the one end (two inches from the edge at each side) and be about 10 inches wide. I was planning on having the overlow side cut 1.5 inches below the tanks surface but I'm not sure that's enough. Any thoughts??

Jeremy

 

[jlinzmaier]

OK. Learned a lot in the last few hours and I have a bit of a change in my plans.

Here goes.

For circulation, I plan to have two closed loops circulating the water in a circular motion from one end to the other from the bottom to the top. I'll have a third closed loop which will cycle on 10 min off 10 min forcing the water in the exact opposite direction of the other two CL's (all three CL's will have OM 4ways). That should add a significant amount of random flow while providing a routine circular pattern all going right at my overflow (that concept was thoroughaly discussed between myself and Paul from oceansmotions and has been the plan for the water flow since the conception of the idea of the tank). I'll have only one overflow at one end of the tank, but I'm still not sure about a few details of the overflow and sump set up. Everything will be plumbed down into the basement so noise isn't a factor. I want to maximize the filtration of my skimmer and will also likely have one or two 100 gal frag tanks set up in the basement plumbed somewhere into the sump set up. I'm planning to have two reeflo orca 250 skimmers which are rated to have intake flow of 500-600 gph each.

With that in mind, I thought a flow rate somewhere between 1500 and 2000gph through the sump would be adequate/ideal (I'll add additional independant flow to the frag tanks). That rate should keep the skimmers continually fed with overflow water (dirty water) and keep the return water to being primarily skimmed water and/or water that has gone through a zeo reactor (clean water). I was thinking that the overflow could merely be a 10 inch extension of the end of the tank and that that end could simply be cut 1.5 in lower than the top of the tank. I'd have two 2-3in drains in the overflow feeding down to the basement.

Any thoughts or suggestions?? Is my sump flow rate an accurate calculation/concept?

Jeremy

 

[murphysfish]

imo, there is no need for two orca 250's honestly, one should probably surfice. If you in deed are going to have two 100g frag tanks, do you think they need clean water or dirty water?

the hard thing to do when feeding your skimmer(s) with overflow water is controlling the flow of it to your skimmer, if you changes in flow your skimmer will not work efficently. it also allows things to get trapped in your skimmer ( not good). look i have two 20 gallon overflows with durso standpipes installed. I have a ehiem 1260 where the drains drain to pump the dirty water to the skimmer. works for me ?

 

[jlinzmaier]

the hard thing to do when feeding your skimmer(s) with overflow water is controlling the flow of it to your skimmer

Not feeding the skimmers with the overflow. Feeding with pumps.

do you think they need clean water or dirty water?

I don't have patience for smart *** comments. Obviously the frag tanks will be plumbed into a location where they will get clean water.

Thanks but your comments were all but completely useless for my original question.

Jeremy

 

[Untamed12]

Re: Help me with my overflow dimensions

<a href=showthread.php?s=&postid=13484058#post13484058 target=_blank>Originally posted</a> by jlinzmaier


The linear overflow size has me a bit puzzled. What exactly is that referring to??

My tank will be 96 in long, 36 in wide, and 28 inches deep. I'm planning to have an overflow at only one end. I thought the overflow would be approx 32 in across the one end (two inches from the edge at each side) and be about 10 inches wide. I was planning on having the overlow side cut 1.5 inches below the tanks surface but I'm not sure that's enough. Any thoughts??

Jeremy

Linear overflow length is the width of the overflow. Above, you mention a plan to have a 32 in wide overflow...that would be your linear overflow size in this case.

You see the math suggests 82", so you would be wise to make your overflow as wide as you can fit on the end of the tank. The idea behind the 82" recommendation is so that a very thin layer of water off the surface is the only water flowing into the box. If you go less wide (32"), then you will pull in a deeper waterfall and pull from the surface less effectively. This all depends on how much water you are trying to move (gph).

You also mention it to be 10 inches wide...I take that to mean that would be the width of the overflow box behind the overflow teeth? If so, that is more than you need. You really only need enough space to ensure you can get the 3" bulkhead in there.

You may have meant the 10" was the depth of the overflow box. If so, that sounds good....especially if you are planning a Herbie drain method (you should), which requires a standing water level in the overflow box. The more height you have in that overflow box, the easier it is to adjust the Herbie.

 

[jlinzmaier]

Thanks for your help Untamed! The 10 in was referring to the distance that the overflow extended past the teeth. The depth will be the same as the tank (It'll all be supported with the same frame so I thought it would be best to create an overflow to sit level with the bottom of the tank.

Jeremy