Please help me decide on overfow

[LagunaGlide]

I have been doing a bit of research since bringing the reef ready 240Gal home that I purchased up and running. The tank originally has dual durso corner overlows with 2" drains and 3/4" returns. The bulk heads are all 1.5". I think I would like to switch the overflow type to something quiter. My original thought was to do a dual herbie and run the returns over the back. I have changed my mind on that, because I would like the tank against the wall, and read it can be very difficult to finely tune 2 drains. All equipment will be in a room behind the aquarium. Drains and returns will go through the wall. I DO NOT WANT TO DRILL MORE HOLES IN THE TANK.

I read about someone doing a Herbie style with the drain on one side, and the emergency on the other with a slight trickle. Both sides had a return. A video was posted and it seemed to run pretty quite. I think this is the way I want to go, but curious if I can move enough water through one drain, and also curious if there are issues with so much flow heading in one direction.

I had a friend suggest herbie on one side, and returns on the other, but the issue I see here is stagnant water in the overflow with the returns. Blocking it off is an option, but seems kind of pointless. Also read about filling it with sand and making it a DSB, but sounds like a pain to deal with when it comes time to clean the DSB.

Same deal with a Bean animal style. Drain and wet emergency on one side, and dry on the other with a return. All of the same issues from dual returns on one side as above. I suppose one could put the dry emergency on the same side as the drain, and the wet emergency on the side with the return, but I think it would be better for flow and circulation to have 2 returns one on each side.

Lastly, am I just best off to keep the dual durso? I really don't like this option, but it is what it is...

Any thoughts and opinions on all this appreciated.

TLDR:
Pro v Cons: Tank has Dual corner overflows 1.5" Bulkheads
Herbie - Main drain one side, Wet emergency other side, Return both sides
Herbie - One side with drains, one side with returns
Bean Animal - Main drain & Dry emergency one side, Wet emergency, 1 return other
Dual Durso - Keep it. Drain and return both sides.

 

[joekool]

edited

 

[LagunaGlide]

The problem you face is the fact that you have 3/4'' for second hole in each one. If you were to have an emergency line it should be of equal value to the siphon.

If you limit the drain capacity of the 1.5'' drain with a gate valve to that of a 3/4'' then you would be fine. You would have less of a turnover rate but it would work.

Is the reason for not drilling or making the 3/4 hole bigger because the glass is tempered???? If its not you can just make the other hole bigger and go herbie drain.

Another note you can always run your return line over the top of tank and in.

Everything is out. I am not really limited by that 3/4" because I am starting from scratch. The Bulkheads are 1.5" and I will put whatever size pipe I need/want from there.

 

[joekool]

You have to contend with the mount of water you can get into the overflow. most of the reef ready overflow boxes are rated at around 600gph an hour but can be pushed over that a couple hundred. One idea would be to make a coast to coast inside with some pvc cut in half and cut into both overflows so that it pulls across the tank and could get you all the water you need. yo just nee to add in some egg crate on top so fish don't get sucked in.

 

[joekool]

Everything is out. I am not really limited by that 3/4" because I am starting from scratch. The Bulkheads are 1.5" and I will put whatever size pipe I need/want from there.

Ok I'm a dummy I missed the all bulkheads are 1.5''

Your golden.

Run one siphon and one emergency in each over flow at same sizes.

2 emergency and 2 siphons 6'' below water. gate valve then siphons only. and you wont have to fiddle with adjustment to much if you let a little water trickle down the emergency drains.

 

[joekool]

When figuring out the flow for my siphon drains and sizing I read this.

Yes water is pulled by gravity. It (for our purposes) behaves like a solid when it is confined by a pipe, so the further it falls, the faster it falls. It pulls on the water above it as well. I will leave it to you to research if the "pull" is created by surface tension or displacement

In any case we use the basic Bernoulli equation to explain how much water falls how fast.

Lets take the 2" SCH80 Bulkhead with a 1.913 inch I.D. and 48" of head.

h = "height" and denotes the head (water height) above the hole.
g = "gravity" denotes the free fall of an object here on earth.. (32ft/sec)squared

So we find the velocity and then plug it into the basic formula:
Q = A * V

Lets do some math:
2" SCH#80 PVC pipe I.D. = 1.913 inches.

So:
h= 6" = 4'
A= 2.873" sq. = 0.01995' sq.
g= 32f/s sq.

Find the Velocity:
V = sqrt(2* 32f/s^2 * 4f) = 16f/s

Find the flow rate (Q):
Q= 0.01995f^2 * 16f/s = 0.3192 Cubic Feet per Second.

The Result:
0.3192 Cubic Feet per Second = 143.25 Gallons Per minute
143.25 Gallons per Minute = 8595 Gallons Per Hour.

Long drop, lots of pipe and fittings... lets say 7250 GPH

Now... the larger the drop, the more friction and turbulance affect the velocity and therefore, the overall flow. Also note that "terminal" velocity is reached much faster due to the friction and turbulance and that cavitation can occur if the pressure drop (caused by the water falling through the pipe) exceeds the surface tension of the water itself....

(‘’Credit Beananimal on reef central”)

Also this might make it easier.

 

[WWIII]

If all the bulkheads are 1.5" that will handle way more water than the overflow weirs themselves, so no issues there. I setup my 200dd which has dual corner overflows in a type od herbie drain/ovwrflow setup. In one overflow I have a full siphon and a trickle, in the other I have a full siphon and the return line. Almost 2 years and it's running wonderfully! It's very quiet and hardly ever needs adjustment. Basically I flush out thr lines because of the gste valve restrictions once a month and reset them.

Going forward, I would not use a tank with corner overflows, but very satisfied with the result of my current setup given the options available.

 

[joekool]

ok so I'll answer your ideas now lol

Pro v Cons: Tank has Dual corner overflows 1.5" Bulkheads (Pro you can run 4 1.5'' drains) no Cons
Herbie - Main drain one side, Wet emergency other side, Return both sides (No use all four holes as drains. Returns over top of tank)
Herbie - One side with drains, one side with returns
Bean Animal - Main drain & Dry emergency one side, Wet emergency, 1 return other (no unless you want more holes need three each side I wouldn't run it the way you suggested)
Dual Durso - Keep it. Drain and return both sides. (noisy as heck you would hate it.)

 

[joekool]

Sorry bud I read back over your first post and edited my replies. Hope it helps and you get what I'm saying.

Let me know if you have anymore questions.

 

[LagunaGlide]

Thanks for the replies. I was thinking the best way was going to be dual Herbie, but really wanted the tank as far back as possible.

 

[ChristmasCorals]

as long as you stick with a gravity overflow your good! for quite operation the bean animal and herbie seem to be popular choices. best of luck.