Silent and Failsafe Overflow System

[uncleof6]

Originally Posted by Augster

I'd like to first start off with props out to Bean, Uncle and the countless others here that have contributed their valuable knowledge and experience in educating us in new methods and techniques that have evolved this hobby to higher levels of satisfaction and enjoyment. My thanks to you all for your selflessness and tireless devotion to this art!

With that said, here is my design concept implementing a BA overflow utilizing an internal weir and external overflow box for an existing glass 100g tank (6' L x 23" H x 18" D). My required criteria were the following:

1) All permanently mounted equipment and plumbing must be housed entirely within the aquarium structure.

2) Maximize "dead space" utilization behind the tank around the drain and return plumbing.

3) Conceal all traces of overflow boxes, plumbing and equipment as much as possible.

4) Isolate vibrations from the external pump by using flexible tubing to connect it to all hard pipes.

5) Easy access and maintenance.



Once I decided on 1.5" drains throughout and 1" return split into 3/4" Loc-Lines, I had to determine the locations to drill the back glass. This required knowing the installed minimum heights and physical dimensions of each channel. I bought a 90 degree 1.5" elbow from a local Home Depot to give me some idea of the space the plumbing would need. As someone unfamiliar with working with this size, I was astounded at how large 1.5" PVC fittings and pipes are!

Hole placement also had to follow these golden rules as gleaned from this thread:

1) The center of the connecting holes between the internal weir and external overflow box needed to be at the normal operating water level of the overflow system, which appears to be approximately the center line of the open channel.

2) The edge of the holes must be at least one diameter away from glass edges and other holes (for the bottom glass of the external overflow, this was not possible due to it's narrow size).

3) The top of the weir should be at the bottom edge of the trim (or at least 1" from the top on rimless tanks).

I came to the realization that if I am to accurately plan a detailed construction list and layout, I would need to either purchase everything in advance and mock up a physical model via trial and error; turn to traditional paper, ruler, compass, protractor and pencil; or go the 21st century way via CAD. Although I have a lot of graphic design work under my belt, this is my first attempt at 3D design and there certainly has been a learning curve to hurdle over, and continue to hurdle through but I feel this has been an invaluable aid in accurately conceptualizing a significant and rather complex project of this magnitude; from construction and drilling of the tank and overflow system, sump, cabinetry cut list to critical placement and space management of all components. Despite some of its shortcomings, Google Sketchup has certainly been very useful, especially the ease to search and download public 3D models from the internet.

Suffice to say, the centerline of the 65mm holes (based on using the same hole saw used to drill the holes for 1.5" Schedule 80 bulkheads from Bulk Reef Supply) are 3-13/16" from the top of the tank.



I selected tinted glass (e.g. Graylite) for the weir and clear glass for the external box. A pair of glass covers over the weir (my tank has a 16" wide glass center brace which necessitates splitting the cover into two)
with 3/8" rubber "feet" keep most critters out of it. To match the thickness of the tank, 3/8" glass will be used.



I saw a potential for the large unused area underneath the external overflow to implement a gravity fed auto-top off system. By squeezing all the plumbing as far to one side as possible and accepting some of the compromises in this tight configuration, I am able to fit a custom 1/4" acrylic 31" L x 13-3/8" H x 6" D reservoir (roughly 10 gallons).



Although I have rendered the back glass of the tank clear to allow easy visualization of the various components, it will be painted black to hide everything from the front. To that end, I extended the weir box bottom to be as low as the external box's bottom in order to cover the entire perimeter of the external's silicone joints to the back (since those points can not be painted to hide it from the front), accepting that water below the connecting holes for such a deep weir may not have enough current to prevent crud accumulating in its bottom. Weir dimensions are 56" L x 7-7/8" H x 2" D while overflow box dimensions are 48" L x 7-3/8" H x 5-1/2" D. The shorter overflow is offset (aligned to left edge of weir, which is 2" from edge of tank) to allow filling of the top off tank. Top of overflow box is affixed 1-9/16" from top of tank (bottom should align with bottom of weir).



To enclose all the external plumbing and leveraging a custom built stand and canopy, I will have a pair of removable vertical opaque plastic panels on each side, notched on the leading edges to allow them to fit flush to the back of my rimmed tank. For illustration purposes, doors and back panels of the canopy and stand are not rendered.

The stand will be built deeper than the tank itself to incorporate everything behind it within it's footprint. As a benefit, this facilitates a direct, straight-down flow of the drain pipes into the sump. Average height figures helps provide scale as this is a rather large ensemble! Stand height to base of tank is 40" to allow ease of access and to fit all planned equipment inside. And by hanging the large reactors above the sump, any water leakage during consumable replenishment will drain into the sump.

I take no credit in the stand and canopy design. For that, my appreciation goes out to Will for sharing his magnificent 90g build. He has since left the hobby but I hope he returns to it again someday as he recently replied to a posting on his old build thread...

DISCLAIMER: I have never had nor maintained a saltwater tank before so I make no claims of knowing what the heck I'm doing! And before this endeavor, I've only had a couple Betta fish bowls. In fact, the only item I have on hand right now is just the tank.

Thank you for the kind words. This post really should be in its own thread, as there are many topics to look at here, aside from the drain system. It deserves to be in a build thread.

The big issue i see is with the pump intake. With your configuration, there is insufficient distance from the elbows to the intake. It lacks the straight length necessary for the turbulence caused in the elbows, to calm down before entering the pump volute. This can and does cause a pump to cavitate. The rule is 15 x the inside pipe diameter, however, often 7 - 10x the inner diameter can keep the pump from cavitating.

Also, i think you would be better served with a single return line, up and in , rather than up over up split dual in -- this will only decrease your pump performance, and you are not gaining anything by splitting the return at the tank. Also would upsize the return plumbing. 1" looks a bit small for that pump: assuming a 1" pump outlet.

[RicoJ]

Is there a reason why bean decided to reduce the size of his bulk head and his elbows inside of his tank instead of using 1.5" throughout?

[rrasco]

I think he said he already had 1" bulkheads or something along those lines.

[RicoJ]

Originally Posted by rrasco

I think he said he already had 1" bulkheads or something along those lines.

Ok so it is ok to go 1.5" throughout?

[BeanAnimal]

Rico,

The tank was already drilled for (3) 1" "durso" style standpipes. I fiddled with them for weeks trying to keep them in tune. This design was born party out of that frustration and partly out of the backlash from at least (2) floods and a few near misses. I upsized the pipe for the open channel to allow more room for open channel flow. In the process, I built all (3) pipes the same size. The larger diameter siphon and emergency both enhance the overall capacity and safety of the system as well.

[rrasco]

I did on my 210. I was also using a reeflo dart/snapper though, so the flow rate was 2000~ GPH and I still had to shut the siphon valve more than I would have expected. Even at that, I think 2000 GPH through the sump is more than you would want for skimming purposes anyways. In my mind, I think you are okay to go that big if the flow is sufficient enough. My reasoning is that if you go 1.5" and try to run a siphon on a low throughput, say 500 GPH, it may not work very well since the plumbing is so large it may have issues creating the necessary pressure for a siphon due to air build up in the large plumbing; might be some unwanted cavitation. My knowledge on fluid dynamics is not to the expert level, so I may be wrong. However, my recommendation would be to go with a something like 1" and shoot for 500-1000 GPH through the sump. The 1" will handle that easily.

[RicoJ]

Originally Posted by BeanAnimal

Rico,

The tank was already drilled for (3) 1" "durso" style standpipes. I fiddled with them for weeks trying to keep them in tune. This design was born party out of that frustration and partly out of the backlash from at least (2) floods and a few near misses. I upsized the pipe for the open channel to allow more room for open channel flow. In the process, I built all (3) pipes the same size. The larger diameter siphon and emergency both enhance the overall capacity and safety of the system as well.

Thank you for the insight sir.

[RicoJ]

Originally Posted by rrasco

I did on my 210. I was also using a reeflo dart/snapper though, so the flow rate was 2000~ GPH and I still had to shut the siphon valve more than I would have expected. Even at that, I think 2000 GPH through the sump is more than you would want for skimming purposes anyways. In my mind, I think you are okay to go that big if the flow is sufficient enough. My reasoning is that if you go 1.5" and try to run a siphon on a low throughput, say 500 GPH, it may not work very well since the plumbing is so large it may have issues creating the necessary pressure for a siphon due to air build up in the large plumbing; might be some unwanted cavitation. My knowledge on fluid dynamics is not to the expert level, so I may be wrong. However, my recommendation would be to go with a something like 1" and shoot for 500-1000 GPH through the sump. The 1" will handle that easily.

Thank you for the added input. I was thinking of going with the eheim 1262 which is a 900 gph pump. I was thinking of going with the 1.5" in case I want to go with larger flow later. I was going to dial down the pipes with the gate valve to compensate for the slower flow.

[rrasco]

It's possible. Just be aware I did the same. Gate valve is definitely the way to go, but even at that with 1.5" I am estimating I had to close it 50% to tune the system at around 2000 GPH.

BTW, Go Miners!

[RicoJ]

Rasco really? You had to dial it that far down? Ok I am going with 1". . I like that picture. Do you have more pictures of your set up? They speak a 1000 words.

[rrasco]

Yeah, I am just estimating, but it was much more than I intended. I think Bean's original article says it should handle 2000~ GPH at 1", so that should be more than sufficient for anything you throw at it.

You can get more details about the BROKEN 210 here. At the end of the thread there is a link to the replacement 105 thread where I also used the bean drain with 1" drains; works amazingly (Thanks Bean!): http://www.reefcentral.com/forums/sh...php?p=19714398

[BeanAnimal]

Your Welcome

Sorry to hear about the loss of the tank!

[Augster]

Originally Posted by uncleof6

The big issue i see is with the pump intake. With your configuration, there is insufficient distance from the elbows to the intake. It lacks the straight length necessary for the turbulence caused in the elbows, to calm down before entering the pump volute. This can and does cause a pump to cavitate. The rule is 15 x the inside pipe diameter, however, often 7 - 10x the inner diameter can keep the pump from cavitating.

Also, i think you would be better served with a single return line, up and in , rather than up over up split dual in -- this will only decrease your pump performance, and you are not gaining anything by splitting the return at the tank. Also would upsize the return plumbing. 1" looks a bit small for that pump: assuming a 1" pump outlet.

I welcome your insight Uncle!

First off, at the moment, I don't know if I can consider myself truly in the aquarium hobby as I only have a bare tank in my possession; no other equipment or livestock. I'm just in the preliminary design stage to allow me to accurately forecast all necessary equipment, supplies and tools (just picked up a miter saw and jointer for the cabinetry work) and plan a budget and project timeline accordingly. Due to the expenses, I think it will be at least 6 months or more before I'm actually ready to get a reef tank underway. No doubt I will start such a thread once I've physically "knee deep", but don't want to "false start" such a build thread in case something sidetracks me before I truly begin...

On to the points raised. Unfortunately, as in life, everything is a compromise No way I could get a straight shot into the pump without removing the valve (requiring full drainage of return stage of sump for pump maintenance) and/or removing the flexible tubing (want to limit any vibration that could lead to premature failure of the sump and elevated sound levels--the intent is for a COMPLETELY SILENT aquarium!), or reducing the length of the standard 36" sump as all compartments are already at minimum sustainable lengths, including the skimmer stage. And this is in a 5 foot long x 2 foot deep cabinet too (don't know if you noticed that part of the cabinet has a bulkhead separating the equipment compartment from the electrical compartment). I chose 5x2 specifically since a 4x cabinet absolutely would not fit all my intended equipment and 6 foot plus and/or 3 foot deep is just too long/large for any foreseeable aquarium location. The absolute criteria that can not be deviated from is that everything must fit within the cabinet, including Auto-Top Off system; no ifs ands or butts! Believe me, I tried every way to make it a straight shot into the pump. If you have any suggestions, I'm definitely all ears! By the way, the inlet is 1" and the distance from the centerline of the last elbow to the front face of the pump intake is approximately 8-1/2" (9-1/2" if measuring all the way to the impeller blades), so that would seem to meet your minimum 7-10x cavitation prevention rule. This is why I love CAD!

Regarding the pump, I'm going with the Snapper, so with guestimated head losses putting me at around 1,500-1,700 GPH, the 1" should be sufficient from all that I've gleaned of flow rates of various pipe sizes. If not, then I can always valve down as I will probably include a valve on the pump output in my final design, which may possibly help with any cavitation issues with lower flow through the "180" intake.

The "over" return line portion was to allow for a custom top off tank immediately below the external overflow; a compromise that favors incorporating a gravity fed top off over any slight head loss due to a more circuitous route for the return.

The "through" return lines were decided upon due to several reasons: 1) to allow the canopy to be removable without having to undo the Loc-Lines if I went the "up and in". It is not shown but the front part of the canopy is hinged and exposes the front rim of the tank completely; the only support is on the sides and along the full width of the rear rim. 2) I will be fully blocking the rear above the rim to prevent light from getting to the external overflow as well as to prevent light from escaping out the back and shining on the wall directly behind where the aquarium is up against.

Finally, Loc-Lines are only offered as large as 3/4", hence my splitting of the 1" into a pair of 3/4" Loc-Lines; better than going from 1" to a single 3/4", or even worse, some unsightly plain 1" piping poking out. It certainly doesn't hurt having the split, yet it does look more symmetrical in design having a pair of Loc-Lines spewing forth and does offer me greater flexibility in adjusting flow output in multiple directions if need be.

Besides, I'm not concerned about attempting to reach an absolute return GPH target number since I'm going with a very capable high flow pump. It already seems quite clear from other's experiences that the siphon drain typically has to be closed quite a bit on 1.5" drains fed by Reeflo Snappers/Darts, so any additional head losses from a more complex return route shouldn't have any adverse effect. That's just my opinion at the moment, of course. Only after I've built it will I know for sure!

[d2mini]

My tank is against the wall (internal coast to coast) and my beananimal plumbing is on the other side of the wall in the garage. So I have a 6" horizontal span between the bulkhead and the 1.5"x1" slip bushing on the beananimal drain. I know the system wasn't designed to have this extra 6" horizontal run but does anyone foresee any problems I should be aware of? I would think once the pipe is filled and the siphon starts it shouldn't be an issue.

[MX175]

Originally Posted by d2mini

My tank is against the wall (internal coast to coast) and my beananimal plumbing is on the other side of the wall in the garage. So I have a 6" horizontal span between the bulkhead and the 1.5"x1" slip bushing on the beananimal drain. I know the system wasn't designed to have this extra 6" horizontal run but does anyone foresee any problems I should be aware of? I would think once the pipe is filled and the siphon starts it shouldn't be an issue.

A 45 degree angle for that 6" section going back is something to consider if you haven't built it horizontally already.

[d2mini]

Ya, i thought about it but i don't have much of a drop on the other side of the wall to my big rubbermaid sump which is elevated, so i figured i'd save the couple inches of drop through the wall so I could maximize drop on the other side. Not sure if it really makes a difference either way.

[danestead]

First of all, thank you to Bean for his knowledge and help to all of us reading this thread.

I have spent the last 3 days reading the first 30 pages of the original thread and now find out there are 193 more to go! I am actually from Australia so usually post on the MASA forums however I've read quite a lot of info on RC of late.

I only have 1 simple question which I am sure has been covered already.

How far off the bottom of the coast to coast overflow box does the bottom of the street elbow need to be on the siphon and open pipe? Is there a minimum/maximum or ideal height?

Thanks in advance.

[d2mini]

Originally Posted by danestead

How far off the bottom of the coast to coast overflow box does the bottom of the street elbow need to be on the siphon and open pipe? Is there a minimum/maximum or ideal height?

You'll see here that beananimal likes his touching the bottom with grooves cut out. Keeps snails and fish out of the drains.

Speaking of which, does anyone have tips on cutting those grooves?
I have a table saw and a tabletop circular saw, but not sure how to go about it without loosing fingers.

And per my question above about the horizontal flow, I hope it works cause it's now plumbed!

[d2mini]

Here's how my drain plumbing turned out.
Just need to run the airline back through the wall to the tank.

[Waggs]

Wow. Must be nice to have so much room for the equipment. Very clean work. Looks GREAT!

[MX175]

Dennis, You did a really nice job cutting and fitting the 3 PVC runs the way you did. Very clean indeed.

Do you have a pic of your overflow setup from the tank side of the wall? Curious to see the entire drain plumbing setup.

[d2mini]

Thanks! Hopefully it works!
The only pics i have of the overflow right now are in my build thread, bottom of this page.
http://www.reefcentral.com/forums/sh...2144250&page=3
Pics don't show it plumbed yet but all you'll see from this side are the bulkheads and the elbows.

Speaking of elbows, if anyone has tips on cutting the teeth on the one end of the elbows, let me know!

[TheFishMan65]

Speaking of which, does anyone have tips on cutting those grooves?

I have had good luck cutting PVC with a Dremel tool.

[BeanAnimal]

To make sure there is no confusion...

There were "teeth" in the elbows on the prototype. My elbows no longer have teeth. I don't feel (in retrospect) that they are needed and are far to dangerous to easily cut with the power tools that most folks have access to.

[jdcook72]

Originally Posted by BeanAnimal

To make sure there is no confusion...

There were "teeth" in the elbows on the prototype. My elbows no longer have teeth. I don't feel (in retrospect) that they are needed and are far to dangerous to easily cut with the power tools that most folks have access to.

What is the clearance between the opening of the elbow and the surface of the overflow box now?