Slow progress on my build but I just wanna make sure I have some measurements right before I get glass cut. Tank is drilled. Holes are 3.25" down from top of tank(rimless) to hole center. With bulkhead and elbows here's the measurements I come up with for the internal c2c. Elbows are 3 1/8" tall + 3/4" under elbow + 1 1/2" to top of internal weir. That leaves about 1/2" for water to go over and into the overflow. Which makes the top of the weir about 1/2" below top of tank. Inside tank width is 46 1/2". So I'm thinking the 2 pieces I need cut are 4"x 46.25"(bottom width weir) and 5.5"x46.25"(height of weir). Is 1/8" too much on each side of weir to silicone?
Silent and Failsafe Overflow System
- Thread starter JohnL
- Start date
greene.phillip
New member
1.25" for the open channel, easier to keep it quiet. 1" for the dry emergency is fine. The bottle neck is the siphon, with a 24" drop, the max theoretical flow capacity for a 3/4" bulkhead is 938gph, not accounting for friction loss, ambient pressure, blah blah, without any pipe attached.
Assuming your estimated flows per pump are accurate, (they probably aren't, due to friction loss) you would have an issue using the water blaster, with any size pipe, and a 3/4" bulkhead"”assuming only a 24" drop. Real world, considering you mention using a 3/4" bulkhead for return and/or splitting the return, your pumps will not be operating close to the flow curve, so I don't see 1" pipe on the 3/4" bulkhead for the siphon, causing a problem. I would not consider using 3/4" pipe useful.
Whether or not either of those pumps is useful for a tank this size, is a seperate question, but I would want to run it up around 1000gph after accounting for the total dynamic head, relegating both those pumps to trash heap, I don't have the specs on the water blaster handy though...
To make sure were on the same page. My stated sizes were referring to which hole (bulkhead) to use. I assumed larger pipe would be used with all of them just wasn't sure 1/4" or 1/2" larger than the bulkhead. I suppose I could make the 4th an additional drain?
Possible to have the holes drilled larger when its already drilled? Not sure if there's room in the box for that.
As for pump I've been also considering one of the DC 6000 pumps which would get it more into the range you're recommending I'd think.
Thanks.
uncleof6
Active member
Redrilling holes can be a bit tricky. It can be done, if you have wood templates and can get the wood clamped down to the glass. Is it possible in your setup, I don't know.
uncleof6
Active member
Something does not sound right. The weir is way too high in the tank... it should be a good solid 1" or so, below the top of the tank...and the drop into the overflow should be around an inch or so...
greene.phillip
New member
Having reread your first response it now makes more sense, forgive my previous response.
Looking closer at the tank the current holes are too close together to redrill larger. It *might* be possible to drill another 1" hole in there, maybe 1.5"
Or I could perhaps drill the back of tank in the area of the overflow box. Have to double check for tempered glass I suppose.
If I drill another somewhere I could do the following:
Returns - 3/4" Bulkhead (1" pipe) x2
Full Siphon - 1" Bulkhead (1" pipe)
Open Channel - 1" Bulkhead (1.25" pipe)
Emergency - 1" (1" pipe)
Coupled with a new RLSS dc6000?
Thoughts?
Looking closer at the tank the current holes are too close together to redrill larger. It *might* be possible to drill another 1" hole in there, maybe 1.5"
Or I could perhaps drill the back of tank in the area of the overflow box. Have to double check for tempered glass I suppose.
If I drill another somewhere I could do the following:
Returns - 3/4" Bulkhead (1" pipe) x2
Full Siphon - 1" Bulkhead (1" pipe)
Open Channel - 1" Bulkhead (1.25" pipe)
Emergency - 1" (1" pipe)
Coupled with a new RLSS dc6000?
Thoughts?
uncleof6
Active member
Why not just pull the bloody thing out of the tank, and start from scratch (assuming the tank is not tempered.) In the long run, you would be happier. Shoehorning a BA into an overflow does not work out so well often, and why I really don't recommend it for corner overflows or overflows similar to yours. I don't know how much room you have, but if the holes are too close together it may be a problem.
Most tank bottoms are tempered, so I don't think popping another hole there is going to work out, and changing the configuration (a hole 'in the area of') may not work out so well either. Depends.
The DC6000 is a nice little pump. It has a 1" outlet, so you are going to want to use 1.25" output plumbing, so you really don't have holes for that...yet... Myself, I would not be comfortable with a 3/4" bulkhead for the siphon with that pump and this tank; a 1" bulkhead with 1" pipe, and you can get 1200gph through that setup (@ 24" drop, max theoretical is ~1669gph @ 24" to show how the pipe size can affect the capacity) and the pump is adjustable. Herbie (2-pipe) is a possible solution without modifying the tank. Run the return up over the back.
If you have a 4' drop to the sump...build it and forget it, you will need to turn the pump down a little bit maybe. 3' is still too close for comfort.
greene.phillip
New member
Well that's not encouraging. What to do with the 4 holes if starting over? Hell maybe I should just get a new tank 
The overflow box is 6x15 so its pretty roomy. The area I was thinking would have been the back of the tank rather than the bottom. Maybe I'll just stick with a Herbie. That's been doing fine on my 90, it just drifts out of tune seemingly frequently and I have to tweak the gate valve. Was hoping this would resolve that. The tank will be on a 3' stand and so really maybe barely 3' from siphon opening to dumping height.
The overflow box is 6x15 so its pretty roomy. The area I was thinking would have been the back of the tank rather than the bottom. Maybe I'll just stick with a Herbie. That's been doing fine on my 90, it just drifts out of tune seemingly frequently and I have to tweak the gate valve. Was hoping this would resolve that. The tank will be on a 3' stand and so really maybe barely 3' from siphon opening to dumping height.
uncleof6
Active member
Four holes? Plugged bulkheads, should take care of that.
Not trying to discourage, rather give all the angles.
The herbie is not as stable, as the BA. That was the idea behind the open channel.
@ 3' the 3/4" bulkhead maxes out at ~ 1148gph. Not accounting for friction loss etc. The head height is measured from the water level in the overflow, to the water level in the sump.
Not trying to discourage, rather give all the angles.
The herbie is not as stable, as the BA. That was the idea behind the open channel.
@ 3' the 3/4" bulkhead maxes out at ~ 1148gph. Not accounting for friction loss etc. The head height is measured from the water level in the overflow, to the water level in the sump.
Just made my template.
Hole center is 2.75" from the bottom of the trim, and if i flip the template over, the next hole will be 1.75" away. Is that a good ratio and is the hole center the proper distance from the bottom of the top trim, which is 1 13/16" in height. Puts my hole center, roughly 3.5" from top of the trim.
Hole center is 2.75" from the bottom of the trim, and if i flip the template over, the next hole will be 1.75" away. Is that a good ratio and is the hole center the proper distance from the bottom of the top trim, which is 1 13/16" in height. Puts my hole center, roughly 3.5" from top of the trim.
uncleof6
Active member
Check it again, that sounds quite a bit low to me...could be just the way you are describing it...The reference point for the holes is the bottom of the trim lip inside the tank. Easier way to find the hole center is to put the nut against the back of the tank, move it up against the trim, then drop it just enough that you can turn the nut on the bulkhead without rubbing against the trim....generally that is going to be where it needs to be. Measuring down from the inside lip will confirm it.
Its possible i worded it wrong.
From the bottom of the trim (using outside as a gauge) is 7/8" to the top of the hole. Center of hole is 1.75" from the trim. Bottom of the hole is 2.75" from bottom of trim. Overflow box is 5.5" deep if I recall.
I can easily change that template.
From the bottom of the trim (using outside as a gauge) is 7/8" to the top of the hole. Center of hole is 1.75" from the trim. Bottom of the hole is 2.75" from bottom of trim. Overflow box is 5.5" deep if I recall.
I can easily change that template.
Last edited by a moderator:
greene.phillip
New member
I would imagine that max would be in a straight down 3' drop? I'll have to cut over to one side to get to the end of the sump as well so it's more 2' down 2' over 1' down.
__|
|
If I drilled a 5th hole it would be at least 1" for each of the drains, the 3/4's would be for returns. Whats the max of a 1" in this scenario?
I guess just as relevant would the two 3/4" returns be able to handle ~1000gph (The dc6000 should be near 1000 with ~4' head and additional losses)
Last edited:
That's not a problem I can make the height of the weir a 1/2" shorter. Which will make the weir 1" above the top of the elbow and 1" from top of tank.
Maybe this will help. From the bottom of the turned down elbow to the top of the tank measures 5 3/4".
uncleof6
Active member
Max is the maxium possible gravity flow through the bulkhead 3' straight down without any pipe attached to the bulkhead. With any pipe attached, there will be friction losses in the pipe, and therefore the max theoretical flow cannot be attained. How much friction loss there will be is a matter of the pipe size, length of the pipes, number and type of fittings etc. Horizontal runs are not recommended, however, you can move laterally (from center to end) by keeping the pipe angled down, with no issues. 45° is best for this. The max theoretical flow capacities are all approximations, and don't account for friction loss, ambient pressure, temperature, viscosity, so forth and so on...the variation in a herbie is due to ambient pressure changes to give you an idea of what is being left out...
Determining what the dc6000 will do, real world, in the plumbing system you build, would be going about it backwards. It is guesswork, unless you really enjoy calculus. What you need to do is get ahold of a friction loss chart, pick a flow rate, and run the calculations (no calculus involved) to determine the requirements for a pump in the system you design. Then choose a pump that will meet the requirements.
Honestly, at this point, you have already invested too much time in it, and are not any closer to an answer...
DC6000: Run a single 1.25" return line up over the back of the tank. Plug and forget the 3/4" bulkhead holes. Run a 1" herbie on the 1" bulkheads. With 1.5" pipe on the 1" bulkheads, you could run the DC6000 wide open...does not mean you need to...We aren't building a rocket ship, and I don't insist that a Bean is suitable for all situations.
DC6000: Run a single 1.25" return line up over the back of the tank. Plug one of the 3/4" bulkhead holes. Use 1.25" pipe on the remaining three bulkheads (2 - 1" and 1 - 3/4") for a bean system. Just guessing, you will get "close enough" to where you want to go...We aren't building a rocket ship, but I don't pretend that the manufacturer of the tank did you any favors with this overflow... They punch 3/4" holes in 180 gallon tanks, imagine the head aches with that if someone wants to hit 1800 gph...and all they have is 1" and 3/4" holes.
I would not punch a single additional hole in the tank. If wanting to punch a hole, move up to the top of the back, punch three holes for 1" bulkheads, pull the existing overflow out, put in a C2C, and be done with the suffering due to a manufacturer's lack of insight. By far, for the system as a whole, that is the best option, but also the most work intensive.
I know, I know, two options to choose from is fairly easy, adding a third increases the difficulty exponentially..
Again, this is not a rocket ship, though I do make it seem so. I put that out there for those that want to hit a specific flow rate, without oversizing or undersizing the pump, rather than taking potluck.
uncleof6
Active member
You have a rimless, I need to be reminded of these things, as I jump back and forth between rimless and rimmed tanks, and it is hard to keep it straight.
Weir 1" down from the top of the tank, and ~1" from the top of the weir to the top of the elbows sounds right. The dry emergency elbow will probably peek above the top of the weir...
My measurements were wrong. From the bottom of the elbow to top of tank it's 5 3/8". So I have to minus 1 3/4" from that. 3/4" below the elbow and 1" from top of tank to get my height for the weir correct? I'm confused. Sorry.
greene.phillip
New member
Honestly, at this point, you have already invested too much time in it, and are not any closer to an answer...
I would not punch a single additional hole in the tank. If wanting to punch a hole, move up to the top of the back, punch three holes for 1" bulkheads, pull the existing overflow out, put in a C2C, and be done with the suffering due to a manufacturer's lack of insight. By far, for the system as a whole, that is the best option, but also the most work intensive.
I know, I know, two options to choose from is fairly easy, adding a third increases the difficulty exponentially..
Again, this is not a rocket ship, though I do make it seem so. I put that out there for those that want to hit a specific flow rate, without oversizing or undersizing the pump, rather than taking potluck.
I'd rather waste time now than put it all together and have problems/regrets.
What's the best way to go about removing an overflow? Seems like quite a challenge.
If you start out planning for a rocketship and you don't quite make your plans you're still better off than if you planned to get by and missed the mark.
I may end up trying to shoehorn the BA in there as you called it lol. Not sure about removing the overflow, would be nice to have it out of the way though. I really want to get away from the seemingly constant tuning with my herbie (which you also helped me with about 1.5 years ago). Pretty sure I could change the pipes over to a herbie without much trouble without taking the tank down anyway and there will probably be several wet runs anyway.
Uncleof6
Measuring everything out the best I could for my c2c. If I put 3/4" under the turned down elbow and 1" above the elbow that will leave me a space of 1 5/8" to top of tank. Will that be too much? I know you said ~1" above elbow and 1" below top of tank. Total height for the weir would be 4 7/8". I hope I got this right. I'm racking my brain over here.
Last edited:
Similar threads
