Here are the questions:
What height should the overflow be, what height should the "teeth" be and how many
teeth at what spacing/size should there by to achieve a 17" to 17.5" waterline at 350 gph?
Full Version: DIY Rimless Tank - Need help with overflow
Check out the attached sketch and see if you can help me figure out a few things. Basically, I'm trying to come up with an overflow box with teeth to wrap around my herbie.
Here are the questions:
What height should the overflow be, what height should the "teeth" be and how many
teeth at what spacing/size should there by to achieve a 17" to 17.5" waterline at 350 gph?
Here are the questions:
What height should the overflow be, what height should the "teeth" be and how many
teeth at what spacing/size should there by to achieve a 17" to 17.5" waterline at 350 gph?
I can not answer the bulk of your questions but I would be more than alittle worried about drilling two holes so close together. Is this a glass or acrylic tank?
QUOTE (D3monic @ Oct 28 2009, 03:34 PM) 
I can not answer the bulk of your questions but I would be more than alittle worried about drilling two holes so close together. Is this a glass or acrylic tank?
Good point.
Glass.
It's still in the planning stages (obviously). What do you think would be a safe distance with 1/4" glass?
If you did the slots with a 1/4" router bit you would be able to fit 14 of them on that overflow if they are 1/2" apart and the water level would be about 3/4" above the bottoms of the teeth at 350 gph.
You might want to reconsider using a 3/4" backup drain though since the backup needs to drain from above the main drain and you'll have trouble getting 350 gph through a 3/4" pipe at the water depth it will need to be at in order to make the herbie work properly.
You might want to reconsider using a 3/4" backup drain though since the backup needs to drain from above the main drain and you'll have trouble getting 350 gph through a 3/4" pipe at the water depth it will need to be at in order to make the herbie work properly.
Thanks mods...
What is the math to finding rate of flow in regards to surface area (fin area/spacing)?
What is the math to finding rate of flow in regards to surface area (fin area/spacing)?
Welcome. 
QUOTE (cptbjorn @ Oct 28 2009, 03:43 PM)
If you did the slots with a 1/4" router bit you would be able to fit 14 of them on that overflow if they are 1/2" apart and the water level would be about 3/4" above the bottoms of the teeth at 350 gph.
You might want to reconsider using a 3/4" backup drain though since the backup needs to drain from above the main drain and you'll have trouble getting 350 gph through a 3/4" pipe at the water depth it will need to be at in order to make the herbie work properly.
You might want to reconsider using a 3/4" backup drain though since the backup needs to drain from above the main drain and you'll have trouble getting 350 gph through a 3/4" pipe at the water depth it will need to be at in order to make the herbie work properly.
How did you come up with the numbers for the teeth?
I agree with your backup idea. I keep letting the idea that if #### hits the fan with my main drain, there will still be SOME water getting through so a 1 inch backup isn't needed. If my main drain is completely blocked, my backup needs to handle everything. 1 inch main and 1 inch backup it is.
The actual calculations are a PITA but I have an excel document saved that does it; I don't remember where I got it so I can't give whoever made it the credit they deserve but it has been pretty accurate to my actual results. Its in metric so it takes a little fussing but I uploaded it to rapidshare here, it's the "flow over weir" section in the middle that does the work.
QUOTE (cptbjorn @ Oct 28 2009, 04:13 PM)
The actual calculations are a PITA but I have an excel document saved that does it; I don't remember where I got it so I can't give whoever made it the credit they deserve but it has been pretty accurate to my actual results. Its in metric so it takes a little fussing but I uploaded it to rapidshare here, it's the "flow over weir" section in the middle that does the work.
Thank you very much!
I'm going to play with it (not that you're numbers are wrong). I just like to "see" everything. I like the mechanics of a system more than the actual inhabitants!
QUOTE (cptbjorn @ Oct 28 2009, 04:13 PM)
The actual calculations are a PITA but I have an excel document saved that does it; I don't remember where I got it so I can't give whoever made it the credit they deserve but it has been pretty accurate to my actual results. Its in metric so it takes a little fussing but I uploaded it to rapidshare here, it's the "flow over weir" section in the middle that does the work.
Is there a reason it's read-only? I'd like to be able to archive this for future use!
No idea why it is read only, that's just how I found it. You can copy the workings into a new sheet and even modify it to gallons and inches if you are going to use it a bunch. I'm more into straight cut overflows so I haven't bothered.
1) please use thicker glass than 1/4"
2) holes need to be the diamiter of the hole from the edge or any other hole to have any level of safty.
3) the primare or main drain should be the smaller of the two holes. search for bulkhead size posted previously on this topic
4) the weir should be as long as posable. teeth may not be nessasry if the flow rate over the weir is low enough. choice of fish (slow swimming like clowns), weir lenght, flow rate sould be at the top of (but not limited to) the list in determining wether or not to use teeth.
will finish my thought when the baby goes to sleep, later.
read the overflow thread.
2) holes need to be the diamiter of the hole from the edge or any other hole to have any level of safty.
3) the primare or main drain should be the smaller of the two holes. search for bulkhead size posted previously on this topic
4) the weir should be as long as posable. teeth may not be nessasry if the flow rate over the weir is low enough. choice of fish (slow swimming like clowns), weir lenght, flow rate sould be at the top of (but not limited to) the list in determining wether or not to use teeth.
will finish my thought when the baby goes to sleep, later.
read the overflow thread.
First off, thanks for the replies and ideas.
I've settled on 1/4" because the Solana is tried and true at that same thickness with a larger area. The tank I'm building is "inspired " by the solana's design. Simple. That's another reason I want to go with the herbie. I don't want anything coming out of the back. So, knowing I need at least a diameter between the two holes. I think my initial design can handle this no problem.
As for the main size compared to the backup size, I was under the impression that you wanted the main to be larger and the backup "can be" smaller. I found this info in this thread: http://www.nano-reef.com/forums/index.php?showtopic=69372
The first page shows the herbie with a large "main" line and a smaller "backup". What am I missing?
I've settled on 1/4" because the Solana is tried and true at that same thickness with a larger area. The tank I'm building is "inspired " by the solana's design. Simple. That's another reason I want to go with the herbie. I don't want anything coming out of the back. So, knowing I need at least a diameter between the two holes. I think my initial design can handle this no problem.
As for the main size compared to the backup size, I was under the impression that you wanted the main to be larger and the backup "can be" smaller. I found this info in this thread: http://www.nano-reef.com/forums/index.php?showtopic=69372
The first page shows the herbie with a large "main" line and a smaller "backup". What am I missing?
QUOTE (bitts @ Oct 28 2009, 06:21 PM)
1) please use thicker glass than 1/4"
2) holes need to be the diamiter of the hole from the edge or any other hole to have any level of safty.
3) the primare or main drain should be the smaller of the two holes. search for bulkhead size posted previously on this topic
4) the weir should be as long as posable. teeth may not be nessasry if the flow rate over the weir is low enough. choice of fish (slow swimming like clowns), weir lenght, flow rate sould be at the top of (but not limited to) the list in determining wether or not to use teeth.
will finish my thought when the baby goes to sleep, later.
read the overflow thread.
2) holes need to be the diamiter of the hole from the edge or any other hole to have any level of safty.
3) the primare or main drain should be the smaller of the two holes. search for bulkhead size posted previously on this topic
4) the weir should be as long as posable. teeth may not be nessasry if the flow rate over the weir is low enough. choice of fish (slow swimming like clowns), weir lenght, flow rate sould be at the top of (but not limited to) the list in determining wether or not to use teeth.
will finish my thought when the baby goes to sleep, later.
read the overflow thread.
Also, I plan on having two clowns and a pearly jawfish, your typical clean up crew (shrimp, crab, etc..) no anemones and of course plenty of coral. Teeth or no teeth? Baby asleep yet?
ok kids down
talk to nano paul about glass if anybody on here counts as an expert about glass, he does. could also look at ada tanks of simular depths. still 1/4" is what they use on 10 gallons which bow, with a rimmless tank thats risky.
check ajmckays thread about doing a rimless for info on silicone.
http://www.nano-reef.com/forums/index.php?showtopic=209500
the thread you linked to is tigahs overflow thread near the end are pics of my herbie 10+10, which may help. just rember that what makes it work is pressure, which incresses with depth. if the back up is higher than there cannot be as much pressure to help incresses the flow rate. thus to have the same flow rate it needs to be larger than the point of restriction on the primarie drain. you may or may not have to use diffrent sized bulkheads. normally this is to much work but could allow for smaller hole which could be closer to the other line and thus fit everything into preexisting overflow.
this may help figure out drain hights
http://www.grow.arizona.edu/Grow--GrowReso...?ResourceId=188
my drain is half of a 4" abs pipe as the overflow, no teeth. feeding 1"main w/ 1" backup. works great but water flowing over the weir is almost a 1/4" high. down side is that my clown ends up in there every now n then. sexy shrimp (befor it was eaten) was in there all the time (once a mounth). next time would double the size of the weir. down sides of teeth. double the distance needed for the weir, and can cause noise.
with what your thinkin of stockin the tank with minamize the flow rate across the weir to a trickle by incressing the langth.
forgot
look into using eductor nozzles to incresses turnover without flow through the drain.
one of the best diy rimless on here.
http://www.nano-reef.com/forums/index.php?showtopic=163883
talk to nano paul about glass if anybody on here counts as an expert about glass, he does. could also look at ada tanks of simular depths. still 1/4" is what they use on 10 gallons which bow, with a rimmless tank thats risky.
check ajmckays thread about doing a rimless for info on silicone.
http://www.nano-reef.com/forums/index.php?showtopic=209500
the thread you linked to is tigahs overflow thread near the end are pics of my herbie 10+10, which may help. just rember that what makes it work is pressure, which incresses with depth. if the back up is higher than there cannot be as much pressure to help incresses the flow rate. thus to have the same flow rate it needs to be larger than the point of restriction on the primarie drain. you may or may not have to use diffrent sized bulkheads. normally this is to much work but could allow for smaller hole which could be closer to the other line and thus fit everything into preexisting overflow.
this may help figure out drain hights
http://www.grow.arizona.edu/Grow--GrowReso...?ResourceId=188
my drain is half of a 4" abs pipe as the overflow, no teeth. feeding 1"main w/ 1" backup. works great but water flowing over the weir is almost a 1/4" high. down side is that my clown ends up in there every now n then. sexy shrimp (befor it was eaten) was in there all the time (once a mounth). next time would double the size of the weir. down sides of teeth. double the distance needed for the weir, and can cause noise.
with what your thinkin of stockin the tank with minamize the flow rate across the weir to a trickle by incressing the langth.
forgot
look into using eductor nozzles to incresses turnover without flow through the drain.
one of the best diy rimless on here.
http://www.nano-reef.com/forums/index.php?showtopic=163883
Bitts (and anyone for that matter) check out this sketch.
The holes are 1.25 inches off the glass edges and 1.25 inches apart.
Will the distances be sufficient for drilling? And does this design (two 1.75" holes for two 1" drains) look good for my herbie?
Note - The sketch is slightly off scale.
The holes are 1.25 inches off the glass edges and 1.25 inches apart.
Will the distances be sufficient for drilling? And does this design (two 1.75" holes for two 1" drains) look good for my herbie?
Note - The sketch is slightly off scale.
That looks pretty good to me, you might consider doing them a full diameter apart and from the wall and just placing them closer to the overflow walls though. If you use schedule 200 pvc for the standpipes they will be able to bend a bit to clear fittings or whatever and assuming you use gray or black acrylic you won't be able to tell the difference when it is all put together.
I think 1/4" glass is plenty as long as everything is well supported by the stand you place it on; 10g AGAs use 1/8" glass and my 15H that I cut down had an 18x20 front panel that was 3/16" thick and it didn't bow measurably. 1/4" glass is almost twice as strong as 3/16" and is four times stronger than 1/8".
Both of the herbie drains I have done were with straight cut acrylic (no teeth) with egg crate to keep stuff out. I also bent the corners of the overflows around a 2x4 that I rounded off with a 1/2" radius router bit. I like the look much better than the typical square boxes with teeth but that could just be my preference. If you look through the water column up at a straight cut overflow it also looks really cool too
I think 1/4" glass is plenty as long as everything is well supported by the stand you place it on; 10g AGAs use 1/8" glass and my 15H that I cut down had an 18x20 front panel that was 3/16" thick and it didn't bow measurably. 1/4" glass is almost twice as strong as 3/16" and is four times stronger than 1/8".
Both of the herbie drains I have done were with straight cut acrylic (no teeth) with egg crate to keep stuff out. I also bent the corners of the overflows around a 2x4 that I rounded off with a 1/2" radius router bit. I like the look much better than the typical square boxes with teeth but that could just be my preference. If you look through the water column up at a straight cut overflow it also looks really cool too
QUOTE (cptbjorn @ Oct 29 2009, 03:44 PM)
That looks pretty good to me, you might consider doing them a full diameter apart and from the wall and just placing them closer to the overflow walls though. If you use schedule 200 pvc for the standpipes they will be able to bend a bit to clear fittings or whatever and assuming you use gray or black acrylic you won't be able to tell the difference when it is all put together.
I think 1/4" glass is plenty as long as everything is well supported by the stand you place it on; 10g AGAs use 1/8" glass and my 15H that I cut down had an 18x20 front panel that was 3/16" thick and it didn't bow measurably. 1/4" glass is almost twice as strong as 3/16" and is four times stronger than 1/8".
Both of the herbie drains I have done were with straight cut acrylic (no teeth) with egg crate to keep stuff out. I also bent the corners of the overflows around a 2x4 that I rounded off with a 1/2" radius router bit. I like the look much better than the typical square boxes with teeth but that could just be my preference. If you look through the water column up at a straight cut overflow it also looks really cool too
I think 1/4" glass is plenty as long as everything is well supported by the stand you place it on; 10g AGAs use 1/8" glass and my 15H that I cut down had an 18x20 front panel that was 3/16" thick and it didn't bow measurably. 1/4" glass is almost twice as strong as 3/16" and is four times stronger than 1/8".
Both of the herbie drains I have done were with straight cut acrylic (no teeth) with egg crate to keep stuff out. I also bent the corners of the overflows around a 2x4 that I rounded off with a 1/2" radius router bit. I like the look much better than the typical square boxes with teeth but that could just be my preference. If you look through the water column up at a straight cut overflow it also looks really cool too
Yeah. I ended up spreading them out a full 2 inches from each other and the wall. As you said, I'll then just put the overflow as close as I can get to the fittings. Great idea on the angled edges and I plan on doing something to that effect. Thanks!
I drilled three holes in my 15 gal. glass refugium (side wall) 3" apart and the glass still cracked. Good thing I only paid $15 for the tank. The glass is 3/16", so it cracks easily. Then I found out that when I lay the tank on a cloth with a solid base and drill against the solid base, the tank no longer breaks. Good luck.
my bad 10gals are1/8" so 1/4" should be good. ( can i blame that one the baby and lack of sleep, sorry )
for a good way of having teeth with out teeth, check tygah's 35gal thread.
scetch looks good, overflow of what 6 - 8 x 4 -5. total weir of 10" at least should be plenty.
make sure to have enough room to put your hand in there to do things. especaily when (it will happen) a fish or crab/snail gets in there, plubming misshap.
for a good way of having teeth with out teeth, check tygah's 35gal thread.
scetch looks good, overflow of what 6 - 8 x 4 -5. total weir of 10" at least should be plenty.
make sure to have enough room to put your hand in there to do things. especaily when (it will happen) a fish or crab/snail gets in there, plubming misshap.
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