Silent and Failsafe Overflow System

[mr.wilson]

Bzar, You won't get surface skimming with three holes or ten for that matter. I would consider sticking with an internal overflow and spend you resources hiding it with styrofoam, cement or rocks. I actually prefer the look of an internal overflow as external ones leave unnatural straight lines.

If you are making the tank yourself it's one thing, but if you are having it built by a professional, they charge $300-500 extra for an external overflow. External overflows make the tank harder to fit through doors and deliver in one piece. If your internal overflow leaks, you would never know it. Your overflow design may also be hard to access if it is located in a hole in the wall.

You may also consider a removable snail strainer so it can be cleaned or redesigned as needed. Teeth inhibit the rate of flow and reduce the surface area by 50%. Also remember that the operational water level in the display will be about half way up the bulkhead, hole or teeth.

You could consider joining the holes for slot if you want to stick with the current design.

 

[Bzar]

mr.wilson: Great info, thank you.

The tank is built...got it for a good deal...$30 for a 90g I was just going to get a diamond core drill bit and make the holes. The external part I will have access to on the other side of the wall. On the other side of the wall will be my fish and sump room...no sump under the actual tank.

hmmm joining the holes to make a slot is a good idea, and would also make it easier to create an insert snail guard....from maybe eggcrate?

I was thinking of painting everything black to hide the lines, and an insert would be flush with the tank wall. hmmm. The external box leaking is an interesting thought...is that a likely event?

 

[mr.wilson]

A leaky overflow is not a likely event, I just plan for the worst and hope for the best. Small boxes are a little hard to affix due to silicone due to the tight clearance. It isn't showing, so you can use lots of silicone and clamp it well when you build it.

If your box is only 4-6" wide it will not clear your wall, so you will have to reach between the drywall to service it. I realize it's accessible from the other room, but the tank never sits flush against the wall and you need more reach around space than you may be allowing for.

You can't argue with $30.00 for a 90 gallon tank. I would still go with an internal box at whatever length you like and run your three drain lines at the end through the hole you are planning. That's just my personal preference.

 

[Bzar]

Ya good point about the width of the box, thanks. Even though the other side is just studs I'd still probably only have a couple inches to get into the box..... hmmmm

Would a half internal coast to coast work? And having the 3 bean's drain pipes through the wall?

I just put together an idea of what I mean...think that surface skimmer too small?

I guess if I'm going to go this way I mind as well go coast to coast...

 

[troylee]

That design will work fine and looks great....only downfall is your still losing the surface skimming by having teeth.....just drop the top of the box down 1/2" to 3/4" and make it a wier where it just takes the top 1/4" of water off and cascades into the box like a sheet of water for best results.......

 

[Bzar]

aren't the teeth needed to stop the snails?

never done an overflow like this....damn snails always getting into trouble in my nano :/

 

[troylee]

That's why we use 1.5" plumbing lol......it would have to be a big turbo snail to plug it up the small ones going for a ride.......either way will work....you can always put egg crate or stainers in front of the bulkheads to prevent snails from causing problems and make the overflow a wier.......I personally left teeth in the back of my tank knowing this problem about surface skimming and honestly have not saw any ill effects on the skimmer...it still kicks azz......I have a pic of my overflow in the last few pages of this thread or click my red house and you can check it out.....I'm very pleased with my coast to coast and would do it the exact same way if I had to do it again....

 

[uncleof6]

<a href=showthread.php?s=&postid=15416051#post15416051 target=_blank>Originally posted</a> by Bzar
Ya good point about the width of the box, thanks. Even though the other side is just studs I'd still probably only have a couple inches to get into the box..... hmmmm

Would a half internal coast to coast work? And having the 3 bean's drain pipes through the wall?

I just put together an idea of what I mean...think that surface skimmer too small?

I guess if I'm going to go this way I mind as well go coast to coast...

Coast to Coast is the most efficient way to go. The longer the weir, the thinner the sheet of water, getting the "organic slick" off the surface quicker.

Regards,

Jim

 

[jb61264]

I use this design with a 36" wide overflow box...my tank is a 75 so it is 48" wide...I get great surface skimming and I can run my corner returns right over the edge of the tank. Not AS efficient as coast to coast but still very efficient

 

[Bzar]

hmmm my post didn't get posted so I'll try again, and sorry if it ends up doubling.

Thanks guys for the help. Lots to consider here. Think for ease and safety I'll be going with an internal coast to coast no teeth overflow. I will put some kind of snail guard on the PVC intake elbows if needed, and put the pipes through the wall behind the tank to the sump room.

jb61264: Nice clean tank, love it. How far off of the overflow box bottom are your elbows? If they can be close I guess a snail guard isn't really needed...I'm also getting the tek light, glad to see others using it.

troylee: amazing tank, thanks for sharing. I might bogart some of your sump idea's...really well done.

 

[jb61264]

Bzar...my elbows are about 1/8 - 1/4" off the bottom of the overflow box...after the first week I had a small diatom grow and there were about three or four snails that lived in there for two or three days and feasted..I had no problems at all with them in there.

One caution...if you have smaller fish (firefish, orange spotted goby in my case) they can get sucked into the overflow...even though my "clearance" is only 1/8-1/4" they did get sucked down so some sort of screen, mesh, or eggcrate should be considered for keeping fish from getting sucked in if you're going without teeth.

Or I guess I just need to buy smarter fish too

 

[JTL]

I am thinking about using 1" bulkheads and 1 1/4 inch pipe and fittings. The 1 1/2" is HUGE. My question is how far down on a rimless tank should I place the holes, and do I put the top of the overflow even with the top of the tank?
John

 

[uncleof6]

Weir (overflow) ~ 1" down from the top of the tank. Holes at least 1 hole diameter to the edge of the hole, from the edge of the glass. You have to do some measuring, and math, to figure out exactly where the holes will be, and center the hole according to where you want the elbow in relation to the floor of the overflow. On a rimless, you may be happier with an external overflow, with the "weir" cut into the back panel, and the overflow "box" siliconed to the back of the tank. Plumbing out the bottom of the overflow.

Jim

 

[JTL]

Couple of things come to mind. Rather than cut in the side panel (my front/back are display sides) why not just reduce the height of the section by an inch or so? I would still have 1/2" on the front/back sections to silicone the external box to. This is still problematic for my setup because I have some obstacles in the way, but it may work for someone else. Another thought is to put a very narrow Weir on the inside and drill holes to let the water flow to the external box or in my case it would be two boxes 8" wide separated by 7". I envision this as being a "reverse" Glass Holes overflow. That would probably work for me, but does it make any sense? I guess that is thinking "outside of the box". If you do an external box would the stand pipes be a different configuration?

Now that I give it more thought I think the two boxes would need to be connected for Bean's method to work otherwise they would operate independent of each other.

 

[teesquare]

maybe this will work.....

maybe this will work.....

 

[Doug864]

Bean,
Can the full syphon be tee'd off with individual ball valves instead off a straight run. I would like to have return flow going to my fuge which is on one end of the sump and skimmer which is on the other end of the sump.
Thanks,
Doug

 

[JTL]

Re: maybe this will work.....

Re: maybe this will work.....

<a href=showthread.php?s=&postid=15420138#post15420138 target=_blank>Originally posted</a> by teesquare

PERFECT! How fast will it go?

 

[teesquare]

a different angle

a different angle

Any questions about external overflows?
T

 

[VegasReefer]

What you are talking about is known to some as a Calfo Overflow, because Calfo made it popular, even though it was based on someone elses design.

You could make a Wier the length of your non visible sides, that would be angled against the back plate, just below the bottom of the cut outs.. This would allow you to have very efficient skimming. then have an external overflow box, boxes connected to them. Most people don't like having the overflow visible on a display side so they set it back a little like this : http://www.reefcentral.com/forums/showthread.php?s=&postid=5783384#post5783384.
A trick that is discussed later in that tread is to use a piece of acrylic the size of the weir with 2 slits and a couple of nylon bolts and nuts to adjust the water sheeting so that it is perfectly level.

Once that is set up, you can use the Bean Animal SFOS inside the boxes, and even if they are separated, they will equalize because they are connected by a common Weir .

Edit... Or you can have one of those made

 

[teesquare]

JTL: approx warp 6

I am trying ot get enough pictures to start a build thread about this one.
T