Silent and Failsafe Overflow System
- Thread starter JohnL
- Start date
Twistofer
New member
I've had good experience with the Flex PVC in that not every angle is 22.5°/45°/60°/90°. Flex PVC is rigid and doesn't flex well for really tight curves, but, on the other hand, it helps with those "almost" and "just about right" fitting situations. In the right situation, it can be very forgiving.
Kingfisher1980
New member
Back with another question. Well actually a series of them.
I built a mock up version of what was going to be my internal box/weir. I used some scrap glass I had laying about, just so I could see exactly how big it would be. It's way too big to be in a 40b. So my first question would be; can I cut some of the street elbow off where it goes into the bulkhead? This would allow me to make the box slightly smaller.
But I instead of even doing that, I'm considering just making a much smaller internal weir 3 sides siliconed in. And then building an external box with 1/4" glass to hold all of the plumbing. I would attach it to the back of the tank with the 3 1" bulkheads I already drilled for the internal setup. I would also remove the paint around the edges of the box and apply black silicone to add more support besides just the bulkheads. I already have extra gaskets to go inside between the tank and the collet and inside the box between the box and the nut.
Does this sound feasible?
I built a mock up version of what was going to be my internal box/weir. I used some scrap glass I had laying about, just so I could see exactly how big it would be. It's way too big to be in a 40b. So my first question would be; can I cut some of the street elbow off where it goes into the bulkhead? This would allow me to make the box slightly smaller.
But I instead of even doing that, I'm considering just making a much smaller internal weir 3 sides siliconed in. And then building an external box with 1/4" glass to hold all of the plumbing. I would attach it to the back of the tank with the 3 1" bulkheads I already drilled for the internal setup. I would also remove the paint around the edges of the box and apply black silicone to add more support besides just the bulkheads. I already have extra gaskets to go inside between the tank and the collet and inside the box between the box and the nut.
Does this sound feasible?
sleepydoc
Team RC
Yes - many people have done external boxes with an internal weir.
Two potential problems with your design that I can think of off hand:
Ideally the pass through holes would be positioned so they are at the water level. This isn't a deal breaker.
Second - you need a minimum of one diameter between the hole edge and any adjacent hole or glass edge. If you're using 1" bulkheads that means the box needs to be at least 5.25" wide.
An alternative is to make a 5-sided box out of acrylic, have matching holes and use bulkheads with a gasket between the glass and acrylic walls to hold it in place. DO NOT try to use silicone to glue an acrylic box in place. It WILL fail.
Two potential problems with your design that I can think of off hand:
Ideally the pass through holes would be positioned so they are at the water level. This isn't a deal breaker.
Second - you need a minimum of one diameter between the hole edge and any adjacent hole or glass edge. If you're using 1" bulkheads that means the box needs to be at least 5.25" wide.
An alternative is to make a 5-sided box out of acrylic, have matching holes and use bulkheads with a gasket between the glass and acrylic walls to hold it in place. DO NOT try to use silicone to glue an acrylic box in place. It WILL fail.
Kingfisher1980
New member
The box that goes on the back will be made of glass and be held in place primarily by three 1" bulkheads. The black silicone will just be added measure to keep some of the stress off of the bulkheads.
The internal box I am not so worried about how wide it is, more about how far it sticks out into the tank. I will likely end up making a very skinny, and long 3 sided box also made of glass so silicone adhesion won't be a problem. The tank is also glass.
Note: the holes I already have drilled were drilled with bean animal spacing in mind. They are below the water level, but they should be fine otherwise. I think they are 1.5" apart and 2"+ from the edges of the glass. My external box will have to be at least 10" wide to accommodate them.
The internal box I am not so worried about how wide it is, more about how far it sticks out into the tank. I will likely end up making a very skinny, and long 3 sided box also made of glass so silicone adhesion won't be a problem. The tank is also glass.
Note: the holes I already have drilled were drilled with bean animal spacing in mind. They are below the water level, but they should be fine otherwise. I think they are 1.5" apart and 2"+ from the edges of the glass. My external box will have to be at least 10" wide to accommodate them.
sleepydoc
Team RC
For the internal weir, you could even have a single piece of glass placed at an angle. Don't go too crazy making it slim as you need enough room to get the bulkheads in & out. (You could place the bulkheads 'backwards' with the flange on the outside and the nut on the inside if necessary. Either way, the easiest is to do a coast to coast - just one or two pieces of glass extending the length of the tank.
As long as your external box is wide enough to safely drill the holes it will be fine. You will also need to have it a bit deeper for the bean plumbing. I'm not an expert on this setup, so I would read back though this thread to get more information on plumbing a bean with an external box.
As long as your external box is wide enough to safely drill the holes it will be fine. You will also need to have it a bit deeper for the bean plumbing. I'm not an expert on this setup, so I would read back though this thread to get more information on plumbing a bean with an external box.
Kingfisher1980
New member
Thanks Doc. I've seen enough videos and read enough to understand the basics of the plumbing itself. I was more concerned with how safe is it to use the bulkheads to hold the box on. Glass is pretty heavy, and then adding water.... That's a lot of sheering force on the bulkheads. I thought about doing coast to coast, but it's a battle getting it inside the tank once assembled.
I'll only be running 600-700 gph so a smaller unit should give me plenty of skimming and flow.
I'll only be running 600-700 gph so a smaller unit should give me plenty of skimming and flow.
Swope2bc
New member
Hi everyone, I am sure this question has been asked 1000 times by now but this thread is massive. I'm preparing the plumbing for my 40b and wonder if I need to use the recommended 1 1/2" pipe? I know the easy answer is no, or it depends on my return pump (jabeo dct 4000 most likely at close to the lowest setting). The biggest question is, though the original Bean design flows 2000+ GPH what would the max flow through 1" be given the full siphon? Thanks for the help!
sleepydoc
Team RC
Max flow through a 1" pipe depends on the drop (longer drop means more help from gravity & higher flows.) In general, you can get several hundred, to over 1000 gph with a 1" pipe at full siphon, so a 1.5" pipe would be more than overkill for you.
Where it matters more is with the open channel/Durso standpipe. This is what gives what I call the silent bandwidth (range of flows over which it flows silently.) A 1" durso standpipe has a very narrow range of flows that it can handle quietly before it starts to gurgle. 1.25 & 1.5" have significantly higher flows.
I would uses at least 1.25" for the open channel standpipe purely for this reason. You can still have a 1" bulkhead and use a bushing to upsize the pipe after the bulkhead.
Where it matters more is with the open channel/Durso standpipe. This is what gives what I call the silent bandwidth (range of flows over which it flows silently.) A 1" durso standpipe has a very narrow range of flows that it can handle quietly before it starts to gurgle. 1.25 & 1.5" have significantly higher flows.
I would uses at least 1.25" for the open channel standpipe purely for this reason. You can still have a 1" bulkhead and use a bushing to upsize the pipe after the bulkhead.
Swope2bc
New member
Sweet, thanks Doc, I will have about 2.5/3' of drop. The sump is directly below the tank (not in a basement). Does the bushing affect my performance given the external box?
sleepydoc
Team RC
No more than it would affect the performance of an internal box. Every coupling, transition, joint, etc adds a bit of resistance to flow. A 1" - 1.25" bushing will add very little if you are going up in size.
Swope2bc
New member
That makes sense, won't the flow max out based upon the smallest choke point though? So with a 1" choke point will the 1 1/4" really help that much?
thejuggernaut
Member
There is friction loss also to consider, so yes a larger pipe will help. But I don't really see any advantage to running 1" bulkheads over 1.5" ones if you are using an external box. If your siphon line has less than 1000 GPH I would switch to 1" piping on that line only, just so it has enough velocity to purge the air during startup. Other than that, there is no negatives and several benefits to running larger bulkheads and plumbing.
Swope2bc
New member
Am I mistaken that Bean used 1" bulkheads for cost with 1.5" pipe? I believe he stated flow rates consistently at or beyond 2000 gph. That being said, the reason I would go with all 1" would be for cost, and because I already have 1" hole saws. Now, if 1" would not be sufficient I could upsize.
Keeping in mind that my return pump maxes out at 1500gph but is a dc pump and will run about 50% essentially. Also, this is only a 40b. Do I truly need to go bigger or will 1" meet my intended use without trouble?
woodnaquanut
Active member
I run all 1" on my 120g tank. My pump is rated at about 1000 gph and the siphon is closed about half way.
I would be concerned with larger pipe you wouldn't have enough flow to properly purge the siphon. I know with my tank as the return pump gets close to needing cleaning, the siphon starts to fail and the system gets noisy.
Swope2bc
New member
Thanks woodnaquanut! Exactly the first hand info I was hoping to find! 1" all around will be the plan. Oh, do you have more than the average drop into your sump? Or is it just under the 120g?
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