Silent and Failsafe Overflow System
- Thread starter JohnL
- Start date
BeanAnimal
Premium Member
Skip the teeth 
Just keep telling yourself that and it will get more comfortable. Like I mentioned, A nice dark lid with several spacers glue to it will do the same thing but not affect surface skimming nearly as much.
Just keep telling yourself that and it will get more comfortable. Like I mentioned, A nice dark lid with several spacers glue to it will do the same thing but not affect surface skimming nearly as much.
uncleof6
Active member
I have been strong-armed into a no teeth weir :twitch:... so here's my latest drawing.
Do the dimensions on everything look OK? Thanks for the help!
So what size standpipes are you going to use? If it is going to be 1.5", you don't have enough room in the external for them, not even sure 1" standpipes will fit in there......
Jim
uncleof6
Active member
2" pipe will be able to handle 3200 gph without even breaking a sweat. 2" will be suitable all the way.
Jim
robojet
New member
Jim... point taken, I was planning on 1.5", although, my flow rate is only going to be around 400gph (Powerheads are what will be creating my flow in the tank) Maybe I should consider 1"?
Either way, I'll need to get some parts and figure out how much space they take. Part of the solution may be to move the holes a bit for a better fit and use an emergency that's a straight up pipe. I don't think there's any problem with that, but if there is, please let me know... something like this:
(I took the photos from others posts in this thread)
I don't see the benefit of doing this with the emergency overflow:
Another option is to follow robertifly's version of an external but holes out the back, rather than the bottom:
So, any comments about an external with holes out the back vs holes out the bottom?
THANKS!
Either way, I'll need to get some parts and figure out how much space they take. Part of the solution may be to move the holes a bit for a better fit and use an emergency that's a straight up pipe. I don't think there's any problem with that, but if there is, please let me know... something like this:
(I took the photos from others posts in this thread)
I don't see the benefit of doing this with the emergency overflow:
Another option is to follow robertifly's version of an external but holes out the back, rather than the bottom:
So, any comments about an external with holes out the back vs holes out the bottom?
THANKS!
So what size standpipes are you going to use? If it is going to be 1.5", you don't have enough room in the external for them, not even sure 1" standpipes will fit in there......
Jim
robojet
New member
I went to Lowe's tonight to get an idea of the "size" of these PVC fittings. OMG! Are you really using 1.5"? (please don't take offense at my surprise!) What did I miss reading through all of this... the photos I've seen implementing this don't look like the huge items I seen in the plumbing section... photo shows 1" and 1 1/2" T and elbow... the ruler has only 6 inches on it. I think I'll be going with 1" unless I've got this all screwed up. The 1" was about 4 1/2" Long x 3 1/2" Tall x 1 3/4" Wide
Last edited:
uncleof6
Active member
I went to Lowe's tonight to get an idea of the "size" of these PVC fittings. OMG! Are you really using 1.5"? (please don't take offense at my surprise!) What did I miss reading through all of this... the photos I've seen implementing this don't look like the huge items I seen in the plumbing section... photo shows 1" and 1 1/2" T and elbow... the ruler has only 6 inches on it. I think I'll be going with 1" unless I've got this all screwed up. The 1" was about 4 1/2" Long x 3 1/2" Tall x 1 3/4" Wide
Yes really do use 1.5" plumbing, and that is small for some systems. Also run 2" pump intakes. For 400 gph, there is no reason to stuff 1.5" standpipes in your external. A 1" siphon will do 1000 + gph.
Jim
robojet
New member
My goodness!
Jim, I'm sorry for having to ask... but in your post, you are saying 1" plumbing is sufficient for my system. But I wanted to verify that you were referring to other setups with regard to the 1.5" and 2" plumbing... not intended for me, correct?
Sorry, I'm not very confident with my understanding of plumbing (I've only had all-in-ones in past), so I'm reading in fine detail and probably making mountains out of mole-hills.
Jim, I'm sorry for having to ask... but in your post, you are saying 1" plumbing is sufficient for my system. But I wanted to verify that you were referring to other setups with regard to the 1.5" and 2" plumbing... not intended for me, correct?
Sorry, I'm not very confident with my understanding of plumbing (I've only had all-in-ones in past), so I'm reading in fine detail and probably making mountains out of mole-hills.
uncleof6
Active member
Would leave the holes in the back of the tank 2 3/8". (no bulkheads) You will probably be able to shorten the external height, don't have a mockup for 1", so make your standpipes up, then figure the size of the external. You want the water level to be at the centerline of the holes in the back, this would be roughly the horizontal centerline of the stand pipe elbows.......
Jim
Jim
jb61264
New member
Originally Posted by jb61264
Trying to figure out where I might be drawing air in my silent/failsafe setup. Its been running great for the last few months, but in the last couple weeks I notice a small surge of air bubbles every 30 seconds or so in my primary siphon...its nothing that I see as serious but considering I had perfect flow for so long, I'm wondering where this could be coming from...I don't have any salt creep in any of my connections so I can't find anywhere where air could be leaking in. Its strange because its not a constant draw of air but almost like a burp every 30 seconds or so...lasts for 2 seconds and then is gone until the next one.
Could there be air creeping in on my ball valve even though there is no evidence of salt creep?
Looks like it was #2...I unscrewed the cap and the overflow hiccuped and then I screwed the cap back on tightly and readjusted the ball valve and everything is tight again...whew
Trying to figure out where I might be drawing air in my silent/failsafe setup. Its been running great for the last few months, but in the last couple weeks I notice a small surge of air bubbles every 30 seconds or so in my primary siphon...its nothing that I see as serious but considering I had perfect flow for so long, I'm wondering where this could be coming from...I don't have any salt creep in any of my connections so I can't find anywhere where air could be leaking in. Its strange because its not a constant draw of air but almost like a burp every 30 seconds or so...lasts for 2 seconds and then is gone until the next one.
Could there be air creeping in on my ball valve even though there is no evidence of salt creep?
Looks like it was #2...I unscrewed the cap and the overflow hiccuped and then I screwed the cap back on tightly and readjusted the ball valve and everything is tight again...whew
jb61264
New member
Can I ask why you guys are recommending to "skip the teeth" in robojet design? One thing I have had trouble with is a few fish taking a ride down the overflow. Amazingly all have survivied and I have no idea how they got down it since the clearance between the bottom of my overflow box and the down turned elbow is like 1/8" or smaller...regardless, the only fish that periled was a firefish early on. I have since added egg crate to my setup and haven't had any further rides I wish I would have added teeth to my design BUT I'm sure it wouldn't be as dead quiet as it is with water spilling through teeth versus a staight piece of overflow
I wish I would have added teeth to my design BUT I'm sure it wouldn't be as dead quiet as it is with water spilling through teeth versus a staight piece of overflow
robojet
New member
Bump to my question.
robojet
New member
I'll try to answer this... kinda scary, since I'm just been asking questions... 
It has to do with linear flow. The more linear flow the better. So, let's say your oveflow is coast to coast on a 48" tank, and you have teeth that are 1/4" and a 1/4" apart, you have reduced the linear flow to 24". A 24" sheet of water also going to be taller as it runs over the overflow, where on the same tank it would be a much thinner sheet of water if the linear flow was 48". This is suppose to be a much more efficient overflow (for reasons I am unable to explain at the moment).
So, what I've seen in some of the posts, is that people will use eggcrate to help keep critters out of the oveflow... so rather than having 1/4" teeth, you only have say 1/16" teeth...
Hope that helps.
It has to do with linear flow. The more linear flow the better. So, let's say your oveflow is coast to coast on a 48" tank, and you have teeth that are 1/4" and a 1/4" apart, you have reduced the linear flow to 24". A 24" sheet of water also going to be taller as it runs over the overflow, where on the same tank it would be a much thinner sheet of water if the linear flow was 48". This is suppose to be a much more efficient overflow (for reasons I am unable to explain at the moment).
So, what I've seen in some of the posts, is that people will use eggcrate to help keep critters out of the oveflow... so rather than having 1/4" teeth, you only have say 1/16" teeth...
Hope that helps.
Can I ask why you guys are recommending to "skip the teeth" in robojet design? One thing I have had trouble with is a few fish taking a ride down the overflow. Amazingly all have survivied and I have no idea how they got down it since the clearance between the bottom of my overflow box and the down turned elbow is like 1/8" or smaller...regardless, the only fish that periled was a firefish early on. I have since added egg crate to my setup and haven't had any further rides
NaClH2Opgh
New member
You could also get an acrylic piece cut that will cover the top. Just put some small rubber stops at the corners and the middle to hold the top up enough for the box to still skimm with no teeth. Make it black acrylic and it will keep light and algae out of the box also.
I went to Lowe's tonight to get an idea of the "size" of these PVC fittings. OMG! Are you really using 1.5"? (please don't take offense at my surprise!) What did I miss reading through all of this... the photos I've seen implementing this don't look like the huge items I seen in the plumbing section... photo shows 1" and 1 1/2" T and elbow... the ruler has only 6 inches on it. I think I'll be going with 1" unless I've got this all screwed up. The 1" was about 4 1/2" Long x 3 1/2" Tall x 1 3/4" Wide
look for sanitary fittings, and then look for "street" 90° fittings
The street fittings have one side the same size as the pipe, so it will just fit right into another fitting. Saves lots of space.
Doing that I got 2 1.5" stand pipes to fit in a standard overflow box with room to spare.
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