# Help with choosing type of overflow box



## chiroken (Sep 25, 2007)

Looking for advice and especially any personal experience. Tank is 8x2', 300g with 6' 120g sump. Euro braced so the entire top perimeter has 3 1/2 of horizontal glass.
The tank has a brutal design for the overflo's, basically turns it into a 6'6" wide tank due to lost space from the overflo's. I want to rip out the existing overflo's and install a rear-wall mounted internal box.

.
I have been very excited to use a glass-holes internal overflow box ( http://www.glass-holes.com/3000-Overflo ... 000kit.htm ) but it won't work out as a standard product they retail. The overflo is 3 1/2 inches front to back and it leaves no space for install or maintainance as it needs to be right up under the eurobrace glass. I have the option of having them make a box similar dimensions but 6" front to back to allow access to the top of the box in front of the eurobracing. They were also good enough to refer me to Reef Savy and their brand new product the Ghost Overflow:

http://blog.aquanerd.com/wp-content/upl ... -Teeth.jpg

The advantage of the Ghost is that the internal box is only just over an inch front to back and the main box is external, I believe 4 1/2" front to back. It has a removable front grill for maintenance. It is probably going to be close to $100 more that the custom Glass-holes box. I think the ghost will also be quieter but I don't think the glass-holes is really that loud to start. A concern with a 6" front to back internal box is shadowing underneath from the light. The tank is 24" front to back and the width (left to right) of the glass-holes box is 18" (again, 6" front to back). I don't know if there really will be much shadowing considering the lights will be at the most placed in the middle of the tank if not slightly forwards of centre.

What do you all think???


----------



## chiroken (Sep 25, 2007)

Here's a pic showing how far into the tank the end built overflo's project:
.


----------



## b3w4r3 (Dec 14, 2012)

I don't see why you couldn't use a couple blukheads and a section of pipe 3 1/2 inches on the glass holes overflow to extend the inner box off the back wall. Maybe ask them for their opinion as there would be some uplift on the inner box due to water pressure, but it shouldn't be enough to worry about.

Alternately you could remove the euro brace and install a couple cross pieces in their place. Could give some support for lights this way too as well as allowing you do do a few sections of glass lids if you wanted to go that direction.


----------



## chiroken (Sep 25, 2007)

b3w4r3 said:


> I don't see why you couldn't use a couple blukheads and a section of pipe 3 1/2 inches on the glass holes overflow to extend the inner box off the back wall. Maybe ask them for their opinion as there would be some uplift on the inner box due to water pressure, but it shouldn't be enough to worry about.
> 
> Alternately you could remove the euro brace and install a couple cross pieces in their place. Could give some support for lights this way too as well as allowing you do do a few sections of glass lids if you wanted to go that direction.


glass-holes said some do it with a bulkhead but he didn't like that method, not sure why. Thought about removing the euro bracing and I do need to figure out how I'm going to support lids. I was looking forward to not having those centre braces that get all stained with evaporation residue. I think part of it is that the eurobracing makes it a "fancy" tank and taking it out somehow is taking something away from it...silly I know.

Tons of searching and I'm now possibly considering building my own glass internal box and going to a Bean Animal system, sounds like they are silent and have multiple failsafes built in. Any opinions/experience with this set up?

http://www.beananimal.com/projects/sile ... ystem.aspx


----------



## b3w4r3 (Dec 14, 2012)

Never used the beananimal/herbie myself. They seem to be an option if noise is your primary concern. My opinion...It's just more failure points/leak potential, and more money for fittings and valves. I like simple HOB siphon overflows. Never had any issues with them in over 15 years of use. If there ever is a problem replacement is very easy.

Not a fan of the euro bracing either, but I do acknowledge it's superior strength for holding a tank together.

Man, those overflows are just senseless. Why would someone do something like that to such a nice tank?

If you do build your own have you thought about how/if you will be adding the typical comb teeth that most overflows have? Without them you will likely have a lot of fish get sucked over the edge. Not that the teeth are perfect, had to fish one of my rustys out of the back box a few days ago, but they really have to jump into it as opposed to getting sucked over the edge.


----------



## chiroken (Sep 25, 2007)

Yes, the tank's design is brutal. I can only think they wanted the tank to be a see thru penisula? But then overflows should have been only on 1 end.

I've looked alot into the HOB overflows and the recurring theme is eventual failure with flood.

As far as teeth....if I venture into acrylic I can cut the teeth myself. If I go glass I was going to do the same as with the current overflows - a strip of black eggcrate was siliconed to the top edge so the water flowed over the glass and through the eggcrate.

I'm not concerned with the cost of plumbing if I'm building it myself. The boxes retail fairly expensive and I can build much much cheaper.

Wouldn't choose eurobracing in the future, didn't realize the limitations they create. Nothing HOB for starters as well as no lid supports etc.


----------



## b3w4r3 (Dec 14, 2012)

chiroken said:


> I've looked alot into the HOB overflows and the recurring theme is eventual failure with flood.


People that have them flood just don't have the water level set correctly. Most know, or soon find out, that the water level in the sump has to be kept low enough so that when the pump is off water draining from the tank won't overflow the sump. The amount of water back flowing into the sump can be controlled by having siphon breaks near the water line. Like I say most know this.

The other concern is of course the HOB siphon failing for whatever reason. With a proper U tube siphon and adequate flow to keep air bubbles moving through it the only thing that can happen is some thing clogs the pipe. Again preventing a flood is controlled by operating water level in the sump. The water must be kept low enough so that if the siphon does fail the water level in the sump will drop low enough for the return pump to start sucking air before the water level in the tank reaches the top. Once the pump sucks air it won't be able to push water anymore, and the tank won't overfill. Part of controlling this balance is the size of the sump. Most pumps will start sucking some air when the water level gets within an inch of the intake, so we want to keep the water level above that point at all times during normal operation. A smaller sump will let the water level drop faster and add less water to the display before it sucks enough air to stop pumping.

Even if you go with a beananimal style overflow you should test the water level in your sump. Once you have everything set up and running, close all drains and let the display tank fill with water. If it looks like it is going to overflow stop the pump! Next drain some water from the system and try again. Eventually you will find a water level that won't flood the tank. If that operating water level is so low that it causes the pump to suck a small amount of air you may want to go to a smaller sump foot print.

Probably more info than anyone wanted, but you will never have a sump related spill this way.


----------



## chiroken (Sep 25, 2007)

Thanks for the reply and info.

I am aware of regulating the sump level so that it doesn't overflow when the DT drains back into the sump during pump shut down (feeding) or a power outage). I don't plan on using siphon breaks as I plan on drilling the returns rather than run them over the top. Will need to account for additional back flow I realize.

My may concern is the HOB siphon failing (ie clogged). I hadn't considered using the low volume on the sump to prevent a pump creating an overflow by pumping too much volume back up into the DT. My problem is I've got a 6'x20" sump so I do have alot of water volume down there. I don't want to have the DT waterline visible so not lots of room for excess water to be pumped into the main tank. With an external pump that is already set via a drilled bulkhead I am limited in changing the pump height (ie raising it). If was was to convert to an internal pump then I guess I could raise it to whatever height I want.

I would love to swap out my 6' sump for a 4 footer but not likely in these parts. The extra space for storage would be great too. The 6 footer plus external pump takes the full 8' of width.

Definitely will test water levels. Previous owner ran this system as a reef and actually has sharpie marks on the tank for max/min. Just need to confirm they're accurate.

I guess what I'm liking about reading about the Bean Animal is it seems to have 3 separate fail safes in the event of clogging. And being as 2 of the 3 are full siphon it can handle alot more water than a pipe mixed with air as in most of the other designs.


----------



## b3w4r3 (Dec 14, 2012)

There are some simple ways to deal with a large volume sump to prevent tank overflows. Putting some good size rocks in the sump, or even bottles of water will make an impact.


----------

