Silent and Failsafe Overflow System

[uncleof6]

SO I am setting up a 40b tank and has some holes in the back. I'd like to do a C2C inside the tank and being there are 4 holes in there what can I do to create the Bean? In the crude pic I attached you can see the dimensions of where the holes are. The outer 2 are for 1" bulk(1 3/4) and the inner 2 are for 3/4"(1 1/2). At one time I had overflow boxes in the corners and return lines in the middle. I can always put the return line over the top edge. The holes are down 2" center from the plastic frame edge on the outside of tank.
Thanks,
Steve

Quite honestly, the flow rate for this system will not be high enough to justify the modifications needed to run a BA system. The C2C idea is fine. For the drains, a Durso at both ends (use 1.5" pipe on the 1" bulkheads) will be more than adequate for silent operation as the laminar flow limit is around 700gph for two dursos, and you are not likely to get above 400gph. (200gph per durso. Laminar limit ~350gph per.) I would perfer to see 1.5" bulkheads however. More room to wiggle around.

 

[uncleof6]

Has some one an opinion about what i describe over?

Marc

I am not too keen on using uni-seals on flat panel glass. They are not rigid, and can result in broken glass, while trying to get the pipe in. Uni-seals are intended for curved, and non-rigid mounting.

 

[sleepydoc]

I am not too keen on using uni-seals on flat panel glass. They are not rigid, and can result in broken glass, while trying to get the pipe in. Uni-seals are intended for curved, and non-rigid mounting.

+1
Uniseals require a fair amount of force to insert the pipes and I can easily see it resulting in broken glass. Bulkheads were made for flat surfaces and are clearly the best answer.

It sounds like what you have would easily accommodate your flow requirements. Why are you so concerned that you want to use uniseals instead of bulkheads?

 

[A_CoupleClowns]

Your question earlier was a bit to wide scoped to answer without typing for most of the day.

Here is a large tank, using "cutouts" in the back panel for the overflow, and an external box with a BA setup. If you can limit the scope of your questions, it will be easier to give an answer.

http://www.reefcentral.com/forums/showthread.php?threadid=1482007&perpage=25&pagenumber=1

LOL!

Thanks. I am going to read that right now, looks like basically the same dimensions as what I am planning too. What size bulkheads would you have the overflow drilled for?

 

[A_CoupleClowns]

Forgot to mention its a 10' vertical drop and about 7' horizontal over to the sump (300G stock tank). Should be a pita.

 

[uncleof6]

Yeah the 7' horizontal run is going to ruin your plans. Such things are not good in a siphon system, as they trap air, causing the drain line to air lock, preventing the siphon from starting up. A 45° angle down would not cause any problems. Spears manufactures odd angle ells, 11°, 15°, so forth, so in most any situation, the pipe can be angled down some, without stressing the pipe and fittings .

1.5" bulkheads for the drains, will fit your needs, however, I would recommend using 2" pipe, to reduce the friction loss.

You are going to need a pretty hefty pump for this too, which will be using 2" - 2.5" to reduce friction losses, regardless of the actual pump outlet size. Most of these types of pumps run 1.5" outlets, some have 2" inlets, and some have 1.5" inlets. They are external, as a sub pump is not going to get the job done. The inlet plumbing needs to be the equal to or larger than the outlet pipe size. That is as far as I will go in this thread with "system design," as this thread is dedicated to the drain system.

 

[Idefixes]

High,

unceof6 and sleepydoc,

Thanks for answer. Why Uniseal :
- i have easy acces to them
- they don't introduce a gap in pipe section
- pipe is repositionnable
- hole is reduce compare to bulkhead

I understand your objection on uniseal use, but pipe introduction is made i bunch easier with a little bit silicon grease on it. Unseal are used in our local aquarium meating group with issue.

Here i used them on a 33G tank

The major things is that you don't see any objetion to the 1.25" pipe use for full siphon drain with my max 800ghp return.
Regards Marc

 

[jc03]

I apologize in advance for my crapoy drawing but I'm wondering what the best way to route my plumbing from bulkheads to sump. The fall is only about 36" but the run is somewhere around 85". Any thoughts would be appreciated. Thanks.


Here's a picture of the front with a 48" piece of rigid foam where the overflow would be. The tank isn't drilled so I'm flexible to other ideas. Excuse the haze. I'm sanding/buffing the blue background off.

 

[hbash]

I apologize in advance for my crapoy drawing but I'm wondering what the best way to route my plumbing from bulkheads to sump. The fall is only about 36" but the run is somewhere around 85". Any thoughts would be appreciated. Thanks.

I think from your drawing that you should try to increase the length of your overflow. You have a 12 foot long tank with a 4 foot long overflow. My implementation also does not have the Coast to Coast configuration as recommended and if you can, I'd try to get closer to that as it does make sense in terms of skimming off more of the tanks surface muck.

 

[stinkyreef]

Quite honestly, the flow rate for this system will not be high enough to justify the modifications needed to run a BA system. The C2C idea is fine. For the drains, a Durso at both ends (use 1.5" pipe on the 1" bulkheads) will be more than adequate for silent operation as the laminar flow limit is around 700gph for two dursos, and you are not likely to get above 400gph. (200gph per durso. Laminar limit ~350gph per.) I would perfer to see 1.5" bulkheads however. More room to wiggle around.

I defiantly am doing the c2c as I ordered the glass, like 11 bucks ea. for the 2 pieces. I just want one return line and I may do either a glass cover over the smaller holes or just a couple of plugged BH's.
Thanks for the help!

 

[uncleof6]

For longevity, use plugged bulkheads.

 

[sleepydoc]

Thanks for answer. Why Uniseal :
- i have easy acces to them
- they don't introduce a gap in pipe section
- pipe is repositionnable
- hole is reduce compare to bulkhead

I understand your objection on uniseal use, but pipe introduction is made i bunch easier with a little bit silicon grease on it. Unseal are used in our local aquarium meating group with issue.

The major things is that you don't see any objetion to the 1.25" pipe use for full siphon drain with my max 800ghp return.
Regards Marc

the 1.25" pipe should be fine for the full siphon.

regarding uniseals -
IME, even with some lubrication you still need significant force to insert them. Your tank is a rimless, so the glass is thicker.

The hole size for a uniseal is the same or bigger than that for an ABS bullhead (from BRS, 1.5" uniseal needs a 64 mm hole, 1.5" ABS bulkhead needs a 60 mm hole). The other thing to remember is that there is significant outward pressure put on the uniseal by the pipe with is then transferred to the tank wall.

The other items of your list may be true but are of questionable practical benefit IMO, execpt the first; if you have access to uniseals and not to bulkheads, that kind of rules out bulkheads.

If you have them installed already, there is absolutely no reason to switch them out, but in general, bulkheads are a better option for glass walled tanks.

 

[Mrramsey]

I apologize in advance for my crapoy drawing but I'm wondering what the best way to route my plumbing from bulkheads to sump. The fall is only about 36" but the run is somewhere around 85". Any thoughts would be appreciated. Thanks.


Here's a picture of the front with a 48" piece of rigid foam where the overflow would be. The tank isn't drilled so I'm flexible to other ideas. Excuse the haze. I'm sanding/buffing the blue background off.

Like this...

 

[uncleof6]

Like this...

Very reasonable solution. I would have got around to that if no one else did... but with me safety and potential problems come first.

 

[Mrramsey]

Very reasonable solution. I would have got around to that if no one else did... but with me safety and potential problems come first.

It was crude but to the point. What fun it would be to build a 12' tank.

 

[CaliCal]

Maybe have 2 BA system on that long tank and all 6 connected to one bigger pipping into one across...I have something like that and works fine.

 

[uncleof6]

It was crude but to the point. What fun it would be to build a 12' tank.

Well maybe... @ 50 - 100 bucks a gallon these days, maybe not so much fun... a 12' tank be useful for small sharks, but personally, shorter wider tanks make a greater impression. JMO. Wider tanks give the depth that is missing from relatively narrow tanks. Make it 400, 500, 700, 1000 gallons, wider is better balanced.

 

[uncleof6]

don't drill yet! maybe have 2 BA system on that long tank and all 6 connected to one bigger pipping into one across...I have something like that and works fine.

No not really. It will be nearly impossible to get two BAs to balance out right, and connecting them all together merely creates one very large durso. It is not going to work so "fine."

 

[hbash]

Still I must ask, as I'm convinced that unlike with respect to bills, more is better. Why no suggestions that an overflow box 4 feet long out of a possible 12 feet is not too small? In fact given that the tank is 400 gallons and assuming that the minimum water being cycled is 2000 gallons per hour minimum (5 times tanks size), the height of the overflowing water above the tank edge of a 4 foot box would be large to accommodate such a rate.

I'm sure U6 has the calculation for how high the water would need to be with a 4 foot width to obtain a 2000 gallon per hour rate and that it is probably quite high. So again, I wonder about the 4 foot overflow out of a possible 12.

 

[uncleof6]

Still I must ask, as I'm convinced that unlike with respect to bills, more is better. Why no suggestions that an overflow box 4 feet long out of a possible 12 feet is not too small? In fact given that the tank is 400 gallons and assuming that the minimum water being cycled is 2000 gallons per hour minimum (5 times tanks size), the height of the overflowing water above the tank edge of a 4 foot box would be large to accommodate such a rate.

I'm sure U6 has the calculation for how high the water would need to be with a 4 foot width to obtain a 2000 gallon per hour rate and that it is probably quite high. So again, I wonder about the 4 foot overflow out of a possible 12.

It really is not necessary to get into the math for this, rather that the principles involved be understood. As far as the mathematics go, Bernoulli's Equation and the Francis Formula come to mind. (one is metric, the other is imperial.)

Both equations are for determining the flow rate over a rectangular weir, based on the measured head height behind the weir, velocity, (width of the channel, width of the weir, gravity, etc.—Width of the channel would be the end to end length of the tank, and width of the weir would be the EFFECTIVE length of the overflow (weir.) It is not a linear relationship, rather a curve. With a little skill in algebra, the equations can be manipulated to give the head height behind the weir, for a given flow rate etc. I really don't see a need to do that with an aquarium, unless you like to push things too close to the top of the tank.

The idea is that we want the thinnest layer of water possible going over the weir, at any particular flow rate. The thinner the layer of water, the greater the percentage of surface water is going over the weir, opposed to subsurface water. Since the object is surface skimming/surface renewal, and the longer the weir, the thinner the layer of water, it is common sense that the longer the weir the better. The longer the weir the more rapidly the surface layer will be removed, and renewed. Don't need the math to arrive at that conclusion. (Just acknowledge the physics are the physics)

Armed with that little tid bit, 2000gph, 30" minimum is a starting point. (calculator on home page.) Remember that is without teeth. Is it adequate? Well that depends. Is that the best that you can do, is it ideal? Well, in a 30" tank it is the best that you can do, it is adequate, and ideal. But 2000gph in a 30" long tank is pretty unreasonable. (we are accomplishing different things in a DT than we are in a sump...) In a 48" tank, you can do much better, in a 12'/400gallon tank it is pathetic, and so is 2000gph. In a 12'/400gallon tank you can do way better than 48" and really need to. The minimum is around 60". I think we get too caught up in what is the minimum we can get away with, given parameters x, y, z. The emphasis should be placed on what is best for the system with parameters x, y, z. That is never going to be the minimums. The hobby is about the critters, not anything else (actually) and the end results will calm the raging lion over the amount of money you spent that you did not want to, or that long shallow overflow that will blend into the background and disappear in a relatively short period of time.