How do you plumb a double corner overflow?

[dreamcatcherr9]

I am still researching and learning how to hard plumb (so I can attempt to do my first hard plumbed sump system).

I finally think I stated to wrap my head around the general concepts, functionality, parts, for a “standard” center overflow box (with 3 holes, 1 main drain, 1 emergency drain, and 1 return line hole to split with a T to have dual return nozzles).

So how do you plumb a double corner overflow box?

Do they have 2 holes drilled (or 3?) If 2 holes, are both overflow boxes having drain and return lines (no emergency, just 1 drain in each overflow box?)

Could the return lines split from 1 main pump (or is it better to have separate return pumps in this case, besides the redundancy / back up discussion)?

How do the hard plumbing not cross paths or become a mess? Because the hard plumbing pvc lines coming from each corner overflow box to the sump would have to cross paths?

Am I making any sense or am I totally lost!?

 

[Hemmdog]

Most likely they will have two holes per overflow. So you can either:
do a durso drain in one of the holes in each overflow and plumb the returns through the other hole. This drain style is usually very noisy, even with every ‘silencer’ mod out there.

do a herbie setup in the overflows(main drain with a gate valve to silence the drain and an emergency drain if the primary drain gets clogged. Then drill the back of the tank, install bulkheads, have your returns wherever you want them. You can also route them over the top of the tank but the finish isn’t as nice and doesn’t function quite as good as drilled with loc-line returns.

take out your current overflows, patch the holes with glass and silicone, drill the back of the tank for ghost bean animal style overflows and drill holes for the returns. Much more space for aquascaping with the overflows mounted externally.

I picked option 1 and I regret it everyday, should of done option 3.

 

[JoshH]

Another option is using the two larger holes (One in each overflow as your Herbie drain and using the two smaller ones as dual return lines. Instead of having a Herbie drain setup in each overflow and running the returns over the back or through the back via drilling. You can have dual returns and a reliable Herbie drain without any of that work. However as mentioned above the dual overflows tend to take up a lot of space so there is that to consider.

 

[dreamcatcherr9]

Definitely no drilling or mods to tank. In fact, I don’t have a tank yet, just shopping and weighing options.

So dual overflow and returns, though I might be fighting noise?

Even if both overflows had gate valves?

I think I’d prefer a single center overflowbox, but I wanted to consider all options...

Thank you.

 

[R.Weller]

Have a look at the 'Overflow' section here:

https://gmacreef.com/

Our 300gal display uses the dual herbie overflow method with over the top returns that are hidden from view by the canopy. If you cannot see the return lines, it should not matter if they are inside the tank or outside. When the syphon is activated, the overflows are silent.

 

[dreamcatcherr9]

Have a look at the 'Overflow' section here:

https://gmacreef.com/

Our 300gal display uses the dual herbie overflow method with over the top returns that are hidden from view by the canopy. If you cannot see the return lines, it should not matter if they are inside the tank or outside. When the syphon is activated, the overflows are silent.

That was very helpful!

 

[dreamcatcherr9]

Have a look at the 'Overflow' section here:

https://gmacreef.com/

Our 300gal display uses the dual herbie overflow method with over the top returns that are hidden from view by the canopy. If you cannot see the return lines, it should not matter if they are inside the tank or outside. When the syphon is activated, the overflows are silent.

Question:

“If you have two pipes in the same overflow with different diameters, then always use the larger one as the emergency drain.”

I thought (in a Herbie, center overflow, with 3 holes, 1 main drain, 1 emergency and 1 used for return line split with T); you wanted the bigger drain for the main drain and the smaller drain for the emergency??

 

[R.Weller]

Question:

“If you have two pipes in the same overflow with different diameters, then always use the larger one as the emergency drain.”

I thought (in a Herbie, center overflow, with 3 holes, 1 main drain, 1 emergency and 1 used for return line split with T); you wanted the bigger drain for the main drain and the smaller drain for the emergency??

Generally speaking, tanks with dual overflows that are drilled on the bottom have two holes in each chamber. Not three. If you have three holes, use the bean animal method.

The largest pipe is the emergency such that you should never overflow the tank from your return. The syphon is calibrated using a gate valve (not a ball valve) to match the volume of water from your return pump. I use dual pumps at 30% capacity using 1" return piping & calibate the 1" main drains on that flow rate. The emergency drains are 1 1/2" so no matter how much water I attempt to pump in the returns, the display will not overflow. So for example, if I were to push both return pumps to 100% without further opening the gate values on the 1" pipes, the 1 1/2" emergency drains will compensate & make a fantastic noise that tells me something is wrong & the system requires attention.