Best Overflow for a 8' tank??? Ideas?

[rkesling]

Helping a friend who is having a tank built

The tank is 8' x 4' x 30" - Acrylic

Now its time to have the builder install an overflow.

I'm thinking a beananimal with a full inside coast to coast overflow - Given the length of the tank and the water turnover that will be in the tank (est 4500-5500 gph using a 6250 gph Dolphin that will sit right under the tank) is it possible, make sense to have 2 full siphon drain, 1 open and 1 emergency?

Thoughts on above idea or others - from builders or those with larger tanks preferred but anyone with knowledge is greatly appreciated - Thanks in advance

 

[mr.maroonsalty]

If I were to do a tank like this I might use a solid colour false back panel for the coast to coast; I certainly would not do a trough. Over the back is an option, but the false back design seems easiest in design and cost. I would drill the bottom and syphon drain directly through the bh's, and use straight standpipes for the backups. You will need a rather large diameter pipe to drain that much water. It isn't at all a syphon problem combining two or more bulkheads into one much larger pipe below the tank, but again be mindful because the backups will need to handle everything.

 

[ca1ore]

Seems like a lot of flow (10x tank vol/hr) through the sump? Although I get that a C2C is probably the best technical solution, I find them too intrusive and prefer to go with a single, larger overflow/weir. Others will chime in I am sure with max flow rates, etc, but I would think you'd need to be going with at least 1 1/2 inch bulkheads and piping to handle that kind of flow.

 

[amlights]

Seems like a lot of flow (10x tank vol/hr) through the sump? Although I get that a C2C is probably the best technical solution, I find them too intrusive and prefer to go with a single, larger overflow/weir. Others will chime in I am sure with max flow rates, etc, but I would think you'd need to be going with at least 1 1/2 inch bulkheads and piping to handle that kind of flow.

I'm new to the forum but have gotten a lot of crap already from defending lower-flowing sumps. I agree, that sounds like a lot of flow through the sump.

I strongly believe there's a point of diminished returns when it comes to weir length on our systems. There are so so so many variables that come into play when deciding what size overflow is best for your tank. Flow rate, stocking, skimmer selection, sump design. All those things can either compliment your overflow size, or not.

Through trial and error my best advice (and I know this is kinda general and not-so-adviceish) is: keep it simple. Our equipment and tanks don't need to be over-engineered to work and work well. Build it just within, or not far outside of your comfort zones (if you want to try something new). Obviously you need to make sure everything is working properly, but you'll have a lot more fun if you don't have to rip things apart and do them over again because something went wrong.

Take, for example, a "reef-ready" 75 gallon tank with a factory corner overflow. Those tanks, with a 1" standpipe are only rated for (I believe) 700-750 gph turnover max. At 80 total gallons of water, at max potential that's still shy of 10X turnover. And, I'm pretty sure most are probably run closer to 550-660 gph turnover. Also, the overflow length is somewhere around 7" with teeth! (That's hardly "efficient" according to all the "experts" here on ReefCentral). BUT, many many many people use reef-ready tanks and have beautiful tanks, grow both SPS and LPS, and wouldn't want it any other way. Why? Because it's simple and it allows them to enjoy the hobby without having to worry about piddily mechanical stuff.

Yes, in this hypothetical 75 gallon and in any aquarium a coast-to-coast toothless weir would be the most efficient at surface skimmer, but, I argue, very marginally considering the tank size and the most stock that can be comfortably kept in the tank.

I am far from an expert. That's just my two cents.

It's kinda like raising a kid. There's no real right or wrong way. As long as you don't totally f* it up, you'll be fine.

 

[amlights]

Seems like a lot of flow (10x tank vol/hr) through the sump? Although I get that a C2C is probably the best technical solution, I find them too intrusive and prefer to go with a single, larger overflow/weir. Others will chime in I am sure with max flow rates, etc, but I would think you'd need to be going with at least 1 1/2 inch bulkheads and piping to handle that kind of flow.

Oh' forgot. There are places on here that reference bulk head size and flow. I personally wouldn't run that flow through anything less than 2" (although that might be pushing it). BUT, I will say I've never built a BeanAnimal overflow or full siphon overflow. I've had great luck (both noise and reliability) with open-channel overflows. Since you want to run it full siphon, make sure you find the right pipe size! =)

 

[Timber77]

Are you wanting to have a loud tank? Seems like your trying to push 3 or 4 times what would be considered loud by most folks. Would recommend a 3 inch drain if your serious about wanting to push that much volume through your sump.

 

[slief]

I had a 240g tank that I designed many years back. The tank served me well for several years. The tank was 8'x2'x2'. I had a pair over overflows situated about 20" from each end of the tank. The overflows were approximately 16" wide at their widest point. They were 3 sided trapezoids so the front edge was substantially narrower than the back. I had the slots running along all 3 edges. Each overflow had a 2" bulkhead in the bottom of it which was overkill for my Iwaki 100RLT return pump. They were black to match the black back. They didn't intrude into the tank very much and almost dissapeared unless you looked close. Due to their locations, they did a great job skimming the surface and I would have been hard pressed to change a thing if I had to do it over.

Having said that, noise was never an issue for me so I didn't run a durso or anything but a durso setup would have worked just fine with this setup.

While a coast to coast overflow may seem like a great idea, I'm not convinced it would have been the best solution as the flow at any point would be neglidgeable compared to a pair of smaller overflows that would have more turblunce or flow.

I only have a few pictures of that tank and these two are the only ones that you can even see the overflows as they dissapear into the black background. I know I was/still am crazy for standing on the edge of the stool like that. 21 years later and I still stand on that same stool. Never a mishap either. Oh and those pants are long gone.

 

[HECS]

I would go coast to coast, I have it on my 150, and I'd do it again. I plumed 11/5" bulk heads rom the overflow and combined them into one 2" line to my sump. It's silent and no chance of blockage

 

[rygar]

I think a lot of people get these monster pumps without knowing why. Doesn't it make more sense to use closed loop systems for water movement with far less water going thru the sump? This would allow the mechanical filtration, skimmer, maybe uv sterilizer, deep sand bed, caulerpa, or whatever you have in your sump to do their thing a little better.
With less water going thru the sump, there is more "gunk" that would be allowed to settle and can be manually removed instead of getting blown around and back up into the water column to settle in the tank where you can't manually remove it.
I think you would be better off getting a pump that was rated for maybe 1000 gph (depending on the skimmer's pumps gph) and get your water movement (turnover) using a couple tunze's or closed loops. 5000 gph is a lot of water to wrangle and keep quiet. My pump was only 3600 gph and it was a battle. Won't ever do that again! And you said your friends would be right under the tank? Don't do it.

 

[ca1ore]

I'm new to the forum but have gotten a lot of crap already from defending lower-flowing sumps.

As long as there is enough flow through the sump to properly feed the protein skimmer, other equipment or canisters, and ensure even heating/cooling between sump and DT, I see no reason to have massive turnover. It is easy to 'argue numbers', but nobody has ever articulated to me a compelling reason for high flow. Required in-tank water movement is far better accomplished with power-heads and/or closed loops IMO/IME.

 

[amlights]

as long as there is enough flow through the sump to properly feed the protein skimmer, other equipment or canisters, and ensure even heating/cooling between sump and dt, i see no reason to have massive turnover. It is easy to 'argue numbers', but nobody has ever articulated to me a compelling reason for high flow. Required in-tank water movement is far better accomplished with power-heads and/or closed loops imo/ime.

+1