Opinion on tank design.

[jwccwj]

Hello I have a question on my tank to be.It concerns the number of overflows and bulk-heads, the tank will be a custom AO with the dimensions 72" long,30" wide, and 24" in height.My plan was either:

A Single central external overflow with three 1.5" drains,one as a drain,one as a return and one for a emergency drain.

BTwo smaller external overflows each with two 1.5" bulk-heads,one overflow with a drain and a return in it and the other with a drain and a emergency drain.

Keep in mind no closed loop is planned and I don't want alot of flow through my sump (ehiem 1262 as return pump) with 4 ft head loss.I do however want to try and gravity feed my skimmer directly from one drain and as of now im planning on a h&S a250 skimmer.Any feed back on this set-up including changes are appreciated.

Thanks....

 

[WinnipegDragon]

If you are getting a custom tank, why are you going external overflow?

Just curious...

 

[jwccwj]

I figured that a external would give more space in the tank,are there any disadvantages to going external???

 

[t5Nitro]

Not sure, but external overflows look a lot cooler I think. Better aquascaping room too lol. I think you would really like the extra 6" width if you went with 36" wide. 3-4" is awesome aquascaping room.

 

[hebygb]

IMO, having had both, and never having a problem with an external overflow, I feel much better about an internal, reef ready tank. I have had some close calls. If you go the external route... it doesnt hurt to double up on the U tubes as a fail safe... one u-tube that goes deeper in the box as a failsafe.

Internals only take up a little more space at the bottom which chances are will be surrounded by rock anyway... having a HOB still has a box on the inside of your tank.

 

[jwccwj]

hebygb Im not sure what you mean by u tube, this isn't a hob style overflow(not exactly), its like a internal just outside the tank,it will have dursos not tubes.Maybe Im just misunderstanding something here???

I think this Months totm uses a external and I really like reefbums desisn here on rc as well.

 

[jwccwj]

Is it because of the weight of the water and the silcon or glue used may be unable to hold up the acrylic box filled with water externally and theres incresed risk of failure??Would two overflows be used to minimize weight per box??

 

[hebygb]

My bad... I hear external and I think HOB. From an aesthetic perspective, I see your goal... I just dont understand your method of moving the water from display to external overflows... If you go with bulkheads as drains, then no matter whether you use 1 or 2 overflows they seem like just pre-sump- sumps and in that case why not route directly to main sump. How will you keep critters from blocking the flow (assuming snails)?

I have seen something similar where the entire back wall was serated and flowed into a full length box which inturn drained into the sump... is that what you are talking about... I think that would be cool.

 

[jwccwj]

Yes the external im refering to will have teeth leading to the box itself and drain through bulk-heads via durso standpipes.These teeth will prevent snails etc from going to my sump.Its a similar set-up to the calfo coast to coast overflow.Its basically the same as a internal just outside the tank,ive heard varing comments on the but I like the look of them and the extra space is nice.

 

[jwccwj]

So any opinions paln A or plan B or will either be ok???

 

[bues0022]

It sounds like you're basically inverting a normal overflow so the extended part goes out the back instead of into the tank right? This creates a flat interior back wall while the exterior of the back of the tank has the overflow topography. I'm by no means an expert, but if it were me I'd probably to the 1x external, the plumbing behind and under the tank seem like it'd be easier. To gravity feed the skimmer just put a Y fitting with some ball valves to controll flow (is it possible to gravity feed a skimmer? what about the needle wheel? Very cool if you can, less power = less $) Good luck!

 

[jwccwj]

I agree bues0022 the single center overflow seems more appealing to me too because it seems less complex and plumbing it should simpler.One drain to skimmer/sump using a gate or ball valve to control water to the skimmer one bulk-head for a single return split with lock-line and the third as a emerg drain.

So anyone know if a gate or BV is better to regulate the flow to the skimmer when gravity feeding it from a drain line?