About overflows pre-made... this time in an Oceanic product question  - 2/4/2006
Hello folks!
<Peter>
I just emailed Oceanic to inquire about the capacity of my 74gal bowfront reef ready tank.  I have heard that it is 1200gpm but I assume this is under siphon (which I don’t want to do because of noise).
<And otherwise ideal conditions... which you/one should not rely on. These 3/4" diameter holes are inadequate... They will change... likely soon... enough lawsuits, complaints>
  I’m considering converting the ¾” return hole in the overflow to a second drain hole to increase the capacity.
<Good idea... not too close to the existing...>
Then I would just plumb the pump return behind the tank and up and over the edge (with a siphon break).  Any reason why this wouldn’t work?  
<Mmm, nope>
Also, to what would you guess the capacity would be increased (would give it a 1” and a ¾” drain).
<Would make this 1 1/2"... cutting over the existing...>
  Would I need to cut the weir slots larger to accommodate the larger flow?
<A good idea... or cut down the height a bit...>
Thanks again for all of your help.  Peter
<Welcome. Bob Fenner>

Re: overflow question  02-05-06
Bob, thanks for the quick response.  One point of clarification...you mention making it 1 1/2" and cutting over the existing hole.  From my understanding, the bottom glass is tempered.  This can't be re-drilled, can it? I've drilled holes in non tempered glass quite a few times...
Thanks, Peter
<Is an issue... am given to understand that there is technology for cutting through nowadays (have never had success with myself), but if I were doing so here, I would likely abandon the one present hole and drill the larger through the back. Cheers, Bob Fenner>

Durso Standpipe in an external (hang on) overflow box   1/31/06
Hi,
<Howdy>
I have a 1 1/4 DIY Durso standpipe in an hang on overflow box.  I purchased the overflow box from my LFS.  The box did not lose siphon in a simulated power outage before I  installed the Durso, but now it does.
<Yikes, or potential yikes>
  The water is siphoned from the inside chamber too fast and siphon breaks.  
<Yep>
I have tried to extend the U tube way below the intake from the Durso, but to no avail. I can't even get the U tube to hold siphon with the power off.  It seems there isn't proper equilibrium between the inside and outside boxes.
Any advice is appreciated, Thanks!
<... Well, there are plumbing arrangements that can be fashioned as a work-around repair here, but they require a bunch of space... more than you likely have. There are other solutions... that call for something other than the Durso you have situated here... and these are posted... you guessed (!) on WWM. Bob Fenner>
- Setting Up a Durso Standpipe -
Hello, I went yesterday and bought all the parts for the Durso standpipes. I have a 1" bulkhead and got all the parts according to the instructions. Problem, I just assumed these items would fit into my overflow, they didn't. I think I might be able to get the 1" PVC, street elbow, tee to fit inside, but the 1-1/4" will not fit for sure. 
<Ok.> 
I read on the website that using 1" PVC is not effective, my tank is roughly 60 gallons. 
<One inch should work... given the fact that you probably won't have nutty recirculation on a tank of this size... would certainly experiment - glue the T-fitting and street elbow together and just press fit on top of the stand pipe... see how that works for you.> 
Any suggestions on reducing the noise? 
<Give this a try first and see how things go... if your tank is still noisy, do read through the plumbing FAQs... I've posted a couple of different solutions there.>
Thanks,
Rajiv "Mickey" R.
<Cheers, J -

Overflow Configuration - 01/23/06
My tank capacity is around 970L.  For return to the sump I have a corner overflow, with two drilled holes.  The height of the return pipe has about 4 in. of stick-up from the bottom.  When I first fired up the tank, the noise of the water flowing into this chamber was unbelievable.
<<I'm sure>>
The guy who built the tank filled this chamber with the same plastic balls used in the wet and dry filter.  This has made a big difference.
<<This is a common method for reducing noise with bottom filled tanks, but many folks have found the use of a standpipe (like the one described here: http://www.dursostandpipes.com/) to be quieter, and also provide additional benefit such as draining less water to the sump in the event of a power outage.>>
On the outlet flow to my sump, instead of the flow being fed direct from 1 outlet, I have placed a PVC pipe, with the ends blanked, across the width of the sump, and drilled holes, so the flow is spread across the filter media.  Your thoughts would be appreciated.
<<Not sure I completely understand your layout/what you mean when you say "across the filter media," but I think this configuration could be unnecessary if not unwanted.  Ideally water pulled from your tank would feed in to a "skimmer chamber" in your sump to be picked up and processed by your skimmer (assuming you have one).>>
Alan
<<Regards, EricR>>

Re: Overflow Configuration II - 01/26/06
Please advise I am correct here.  I can remove all the 3 different items I have in the first chamber, and place the skimmer there to receive the raw tank water.  The water would then flow over the top in-to chamber 2 passing through the Poly Filter and Carbon.  And then to the last chamber for return.
<<Correct, but understand I'm basing my opinion solely on generalities and the small amount of info you have provided.  Other factors to determine your decisions are what type of setup you have, other/supplemental filtration methods, etc..>>
I do not know what you mean by a filter sock and where to place this item.
<<Essentially, this is a filter bag placed over the end of the overflow line to the sump.  A search re on the net/this site will yield more info.>>
If I leave the setup as it is where best would it be to place the carbon and Poly Filter.
<<Somewhere where water will flow over/through the media.>>
Please note in the main tank I have no live rock only crushed coral on the base.
Regards
Alan
<<Looks like you need to do some research/reading.  Let me get you started here: http://www.wetwebmedia.com/marine/setup/filtration/marineFiltr.htm  
and do follow the indices in blue at the top of the page as well.  Regards, EricR>>

Re: Overflow Configuration III - 01/28/06
Thank you for all the help you have provided regarding this subject.
<<My pleasure>>
I have one last thing to ask you.
<<Ok>>
All my water parameters are within spec, except for the following.  I have added a ORP controller, and calibrated the probe using 400 ReDox fluid, the probe is in the sump in the same chamber as my return pump. The controller has been running now for two weeks, I am only able to obtain a ORP reading of around 212 max.  Please note I have not yet connected the ozonizer.
<<When you do...shoot for an ORP of 330-360.>>
The tank is low stocked and the water is crystal clear.  Even after a partial water change the ORP has remained about the same.  My pH is also measured by a monitor and remains constant at around 8.23.  The only area with flow in my sump is at the outlet from my overflow.  Would it be ok to do the following.  First use the white wool which I have at present to trap the incoming dirt,
<<Ok...but be sure to replace weekly.>>
under the wool I would place poly filter, and under the Poly-filter I can place the carbon.
<<Should be fine.>> Also would adding a larger than required skimmer improve my ORP.
<<It could, but likely not significantly.>>
Also at present I am not using any carbon or Poly-filter.
Alan
<<Regards, EricR>>

FOWLR Turnover & Circulation   1/18/06
WWM,
<One of us>
Your site is great – thank you.  I have been reading it almost every other day for about 2 months now. Think I am now ready to ask some (hopefully intelligent) Q’s.  I have a 125g glass tank (18”W x 72”L x 22”H) in the wall - planning a FOWLR.  B4 I start ordering things (want to soon), I have some Q’s.  My goal is to keep $$ down w/o tank looking like crap or killing fish.  Here goes:
Turnover:
Q1) For FOWLR tank:   can I “get away with” about 8X turnover (knowing 10X -20X is “best”)?  I am thinking of going with a 1,200 gph capable overflow box, but I’d be limited to 8X if I go with a less power hungry return pump as below.
<Yes>
Details:  I have 5.5’ from floor to tank top, so I figure about 6’ of head.  I am debating return pumps between OceanRunner 6500 vs. Mag 2400.  OR6500 flow is only 1,050 @ 6’ (8X) but only uses 115 watts (annual cost of $140 for my area).  Mag 2400 pumps a nice 1,700 gph @ 6’ (getting me to 10X max of overflow box after gate valve reduction to the Mag), but the thing uses 265 watts costing me $315/yr !!
<You are wise to consider energy consumption and cost>
  Since there’s only a diff. of 2X turnover (unless I  add a 2nd OF box w/ Mag 2400) , I’d rather not pay an extra $175/yr if I can get away with the OR6500 (but don’t want to threaten fish or have noticeably worse water clarity).  What to do?   Beyond the 2X difference above, would adding a 2nd OF and getting the full 1,700 gph (taking turnover to 14X) be worth the extra $175/year in electricity in terms of fish health and/or noticeable water clarity? (or only if I ever go reef) ?
<I would start with the smaller flow rate pump for now>
Circulation
Beyond turnover, not sure how critical circulation is for FOWLR tanks – seems like a very big deal for reef tanks.   Can I can get away with just the circ. from the OR6500 return or do I need some add’l in-tank circ.?  
<Can be added later...>
If so, I’d probably build a top-of-tank manifold  (unless I can  hide powerheads behind my rock which seems likely tough with a tank only 18” deep). I'd only consider powerheads because 2 smaller powerheads + OR6500 would still be less wattage than the Mag 2400.  If I go with manifold, I understand I would clearly need the Mag2400 or higher.   
<Likely so, yes>
Overflow Q’s:  Not a reef-ready tank so must use OF box.  Read bad things about CPR losing siphon so will use a box w/ J tube(s).
Q1:  I understand that in the event of a power outage, if sump has enough capacity to hold water draining from OF box & pipes, and provided return lines have anti-siphon holes, no flooding should occur in sump (please confirm).
<This is a correct statement>
How many, where & how large do the anti-siphon holes in the return line(s) need to be?
<"Over the top", "inside the tank, just below where you might want to have your regular water level at its lowest>
I thought I read two 1/8”holes on opposite sides of each 1” PVC return pipe about 3/4” below water level but can't find now?  
<This is about right>
Q2:  I understand that if the OF box siphon has broken, when the power comes back on & return pump starts, main tank could flood. But, if the water in the return compartment of a Berlin style sump is only a few gallons because of the sectional nature of the sump, then is that the max. amount of water that could come back into tank (probably not enough to flood) since no more coming from OF box?
<Correct... but a pain to deal with such a small transit volume in terms of keeping the system "topped off">
Q3:  If correct, then is “worst case” of siphon breaking:  a) potential pump burn out once water in sump return compartment is gone (does such burnout apply only to submersibles or externals too?), and b) hassle to restart OF siphon?
<Does apply to both types of pumps... once run more dry, their time is limited. Not hard to re-start these siphons... top the tank off, suck away or fill lines and drop...>
Q4:  Is having two 600 gph OF boxes better than one 1200 GPH?
<IMO/E, yes>
  If so, why, and I’m confused about something:
<In case one goes, the other may save your pump/s, livestock...>
If I have a 1200 gph return pump and two 600 gph OF boxes, and one OF siphon breaks but the other keeps working, don't I run the risk of main tank overflow (since the sump will still be getting 600 GPH from the working OF but the return pump will be pumping 1200 gph back to tank?)
<Not much... you can/should try this out to determine your maximum fill mark in your sump...>
Isn’t this worse than having only 1 OF with a broken siphon (where water flow back to tank is limited to sump return compartment)?  Or, is some equilibrium achieved at 600 gph due to compartmental design of sump as it only pumps back what is in the return compartment and this is limited to 600 gph?  Would it be a “jerky” flow (where water flows into sump return box at 600 gph & gets pumped out at 1200 gph, leaving the return compartment dry for a few seconds before it fills again?
<Will oscillate a bit, with the pump losing capacity (air lock around the impeller), catching up and then losing...>
Sorry I am so confused here, but trying to determine if 2 OF’s is better than 1 OF box.
Thank you,
Paul H.
<Thank you for sharing. Bob Fenner>

Siphon Overflows
Hello,
<<Howdy>>
I had a question about possible flooding with hang on overflow boxes, since I live on the second floor of an apartment building am a little concerned.
<<And rightly so...>>
I have a 75 gal tank with 2 CPR CS90 overflows, a 20 gallon sump, with a MagDrive 7 pump.  My question is would it be possible to use an auto top off device connected to the return pump with the sensor sitting high in the tank keeping the pump constantly running, if for some reason I had a siphon break, the sump would then fill the main tank triggering the float switch, shutting down the return pump and avoiding a flood.  Would this work and if not do you have any other suggestions for me?
<<In theory maybe, but float switches can fail too.  Is good that you have two overflow boxes...do have a read through our FAQs re:  http://www.wetwebmedia.com/ovrfloboxfaq2.htm >>
Thanks a lot for your time, Chris
<<Regards, EricR>>

Overflow from a mini-reef  12/14/05
Hi guys/gals.  I'm setting up a small 16 gallon mini-reef tank to put on my desk and have a question for you.  This is a small bow front tank to which I plan to add overflows. My plan is to drill dual 1/2 inch holes <RMF would make these a minimum of 3/4 inch> (one in each corner) in the back glass and attach PVC "Ls" to each with an enlarged fence atop.  The bottom of the tank is tempered or I would drill there.  My question is this: from your experience, does it matter how deep (distance from the top of the tank to the center of the hole) these holes are drilled?
Obviously, one would want to leave room for the pvc L and enlarged fence piece, but for aesthetics, I would like the hole to be as close to the top as possible so you don't see the pipe run the whole depth of the tank.  Or
in other words, the pipe would enter from about 4 inches (or so) below the water surface and then make a 90 degree up into the larger diameter fence.
Is there any disadvantage to this as opposed to drilling the hole near the bottom of the back wall with a longer section of pipe between the fence and L?  My other tank is a reef ready 100gal so I didn't have these problems.
<There is no advantage to having a longer pipe just to bring the water from the surface down to a low-positioned drain hole. You can drill as close to the top as structural/glass integrity will allow and your plumbing/elbows will accommodate.>
Thanks for the advice and for all the other help I have gotten from your
site throughout the years.
<Always a pleasure. -Zo>
Peter

Reef ready (built in pre-filter) vs. Over-flow box  11/18/05
Hello buddies,
<Howdy>
I have a 60R 48x15x18 acrylic tank that I scratched up a bit and I can't remove the scratches and retain the original luster. Anyway, I was thinking for about $200 I can get another clear-for-life 60G same dimensions except 2" inch taller which would give it more volume and larger vertical viewing. Since the length and width are Identical, I know I can use my stand and canopy. It's only 2" deeper (20") so my lighting should still be ok.
While I'm at it should I get one with a built in pre-filter box? What are the pros and cons? (i.e. noise, flooding when main pump fails, takes up a considerable area of tank, better circulation of main water to sump, etc, I'm already using LifeReef's pre-filter box but I could use it in another tank.
Thanks, Anthony
<You've about covered the pros/cons... except there shouldn't be a chance of flooding... I favor this approach way over over-flow boxes. Bob Fenner>  

Overflow  11/9/05
Hello everyone,
<Sam in Malaysia>
I have a 4'x1'x1' tank that I would like to have 2 x 25mm overflows. I thought this would help with the flow of water since I'm using a 5000L/hr water pump that sucks the water really fast.
<Faster than these overflows/intakes will allow>
Current residents of the tank are 3 tubeworms, 1 yellow tail damsel, 1 fire goby, 1 pink antennae, 1 button polyps, 1 flower pot, 1 star polyps and Caulerpa macroalgae. I have about 10 kg.s of life rock. Your help is very much appreciated. 
Sam
Malaysia
<... help with what? You likely need more and/or larger intakes... Bob Fenner> 

Vertical vs. horizontal bulkhead flow-WOW 11/2/05
Hello all and a pre-question thank you!,
<Welcome>
Visited a LFS last week, Pacific Reef in Fountain Valley, Ca. Awesome store. Three 200g reef tanks displayed, plumbing and all. One SPS, 2 LPS/soft.
<Area has had a history of great stores>
The tanks each run with 2 T-4 Velocity return pumps (now called Poseidon's I think) listed at 1250 gph at 4ft of head. They're all 7x2x2, exactly the size I'm planning for myself.
This provides approx. 2200 gph, I think. The surprise to me, and my question, is that each tank has only 1 overflow box with 1- 1and 1/2 inch hole. Now, he (owner) had to knock some teeth out of the top of the overflow box to let in the overflow water. (not at all surprised here, they're only 7x7 inches) BUT, the 1 and 1/2 inch hole handles the overflow of 2200gallons. The water level in the overflow box is elevated a bit (about 1-2" ) but the water volume is not rising, it is handled at that level.
<Yes... from a drain/fitting at the bottom, vertical... actual gallonage moved not likely more than 1,500 gph>
He operates the pumps with 1 inch intake and outflow, but reduces to 1/2 inch with a 6" LocLine at the 2-1" bulkheads on each tank to increase velocity.
<Make that 1,000 gph likely>
Oh, each T-4 has only one 1" tube up to a 1" bulkhead. 2 total returns in each tank. 2 pumps up to 2 1" holes. All water flows through a sump.
Am I correct that a 1 1/2" hole in bottom of overflow box can handle about 2000gph?????
<Mmm, no... not likely>
I saw it with my own eyes, I think. This is a hole (sorry) lot more than a 1 1/2" hole, id, drilled in the back of a tank, isn't it?
THANK YOU
Peter
<Would suggest, if folks are interested, actually testing the flow rate, timed with buckets of known volume... Bob Fenner> 

Re: vertical vs. horizontal bulkhead flow-WOW 11/3/05
Hello Mr. Fenner and thank you so much for the reply,
<Welcome>
A little foggy on this still. Are you saying that only 1000gph is flowing through that 1 1/2" hole? How possible when the 2 pumps are rated at 1250 @4'?
<Twists, turns, induced drag... am not saying a specific gallonage BTW, but encouraging you to actually test>
Also, visited Tong's LFS today in same area. Great store, too.
<Very nice stores, folks>
I asked the owner, Tan, "how much flow would a 1 1/2 id hole at the bottom of an overflow box get. He said 2200-2400gph. Aaahh! help! Would you please help me out here?
<No need for help... measure it>
Tan also said that a 2" hole would drain over 3000gph. He said the same hole drilled in back of tank drains significantly less water.
<Yes>
Maybe 1/2 as much. He sets up and plumbs many of the tanks sold there. I know I'm missing something here, question is where? Is the reduction through the bulkhead from 1" to 1/2" LocLine the key here? If yes, what about Tan's numbers? thank you
<... a bucket of known volume, a time piece with seconds measure...>
I read your site religiously and am truly grateful. Thank you for the privilege of corresponding with a person of your expertise. I will never wash these keys again!!
<Heeeee! Let's not go overboard. Better to have larger fittings (for flow, noise reduction, safety margin should there be a clog/slow down in the drainage...). Do please get the simple gear, measure the actual flow and report back to us. Cheers, Bob Fenner> 

Mangrove and bulkhead questions 11/1/05
Hi, I had two quick questions that I would like to ask your staff. The first one involves red mangroves. I recently purchased a red mangrove pod from http://garf.org, it did not have the roots or stems growing yet. I have had this floating in my sump, with a grow light, and the roots are sprouting very nicely. My question is, at what point do I remove the pod from the Styrofoam that it is floating in, and begin to establish a root system?
<Yes>
I will eventually be moving this to a 25g tank aside my 125g tank. I wanted to have the tree elevated on pvc pipes so that the roots are exposed and have lots of room to spread out, or something of that nature. 
<Better to have rooted in a fine substrate...>
What methods do you recommend for something of this nature?
<Please read here: http://wetwebmedia.com/mangrovetrees.htm and the linked files above>
My second question is about my overflows in my 125g. One of my black overflows has a bulkhead built into the body of the overflow. This bulkhead is approximately 5 or so inches off of the sand bed. When I turn off my return, there is a slow trickle of water that continually comes from that overflow. The bulkhead does not make a secure fit with the walls of the overflow.
<Not good>
I am concerned that the power will go out when I am not around, and this will cause a slow flood in my apartment.
<You are right to be concerned here>
I have the bulkhead fitted with pvc pieces and a cap, so that no water flow goes through the bulkhead, it just seems to come from around the seal. Do you have any suggestions about how to stop this bulkhead from leaking?
<Yes... requires draining the tank, drying the area... removing the bulkhead, smearing a bit of Silicone sealant on the gasket/fitting on both sides (in/out of the tank)... allowing to cure for a day>
The tank is up and running with about 120lbs of LR and 3 fish, so draining it all the way down to silicone the bulkhead does not sound appealing.
<More appealing than the water on the floor to me>
I thank you for all of the help you have given me so far, and undoubtedly the help your site will give me in the future.
<A pleasure to share. Bob Fenner>

External overflows... some poignant input  10/19/05
I have read any and all questions regarding external overflows the type with the j tubes and didn't see any thing about using check valves  to prevent water from spilling out on floors.
<... how would you do this?>
I have a 46 gallon bow tank that isn't drilled. The tank is running two years with no prob. Cant buy a bigger new drilled tank yet due to a baby on the way very soon. I eventually will though but in the mean time I have a external overflow I plan to use along with a ten gallon refugium I made that will go underneath the display tank. The overflow bulkhead is 1 inch. Which is better for a return line? 1/2 inch or 3/4 inch ?
<... the size of the discharge on the volute>
The pump being used is a Hagen 801 powerhead. I think it puts out about 800 gallons per hour. My current filter is a canister which I plan to eliminate when I get this refugium up and running ,puts out 167 gph.
<Where are the spaces between your sentences? What a waste of time>
Can a  pvc swing type be used on the return line?
<Yes, but why?>
A swing type I guess couldn't be used on the suction side because it would be mounted vertically and the check valve would be mounted with the arrow facing downwards rendering the valve useless. Can  normally closed
solenoid  valve be used  in the return line ?
<... for what purpose/s?>
These solenoids are open when there is power and close when power is interrupted .
<Ahh... I would not rely on this/these... too likely to fail, not re-open, rust...>
A spring type I guess wouldn't work cause the water is gravity fed and the isn't enough pressure.
<Yes>
I really want to set up this refugium now but I'm afraid of finding water on the floor like I read in some of the postings. The reason I mention check valves is to keep the water in place and  continue flowing once power is restored without intervention.  
<I see... but again, I discourage you doing this...>
No water on the floor or my a*% is grass. Please help me. Any info on how to somewhat foolproof my system from having water on my floor would be appreciated.
Thanks Harry
<Perhaps a large pan, dam around the area... maybe even a drain within same? Two overflow boxes are better than one... Bob Fenner>

Bulkheads... getting ready to drill, planning plumbing 10/12/05
Hi guys!!!! Like to say it again, great site and info... I am getting ready to drill my 100 gallon tank at the top. I was wondering will 1 2" bulkhead get me by with enough flow for SPS?
<Mmm, I encourage you to consider two... maybe 1 1/2" ID... better to have in opposite, upper corners...>
I am going to be using a sequence dart. I guess how much gph will I get with a 2" inch bulkhead? 
<Depends on subsequent factors... of plumbing, turns, water level over...>
Or should I drill for 2 2" bulkheads.
<Much better>
I just want to get by with one if possible because it makes me nervous drilling the tank. Also will it be fine and the same flow if I just have it flow straight to the bulkhead with a strainer. Or should I put a 90 degree fitting on it with a strainer inside the tank. Thanks and hope this makes sense. 
<Mmm, better to use strainers for sure... and a good idea for you to check into using "Tees", aspirating the lines after... for noise reduction, flow... Bob Fenner> 

Full length overflow weir question  9/29/05
Hi Anthony, James & Crew,
                The 48x24x24 tank is already built and it has two 2" holes
drilled, one in each corner at the top of the rear panel.<Understand, that is why I suggested the item in the original query.> It also has four 1" holes drilled across the back panel evenly across and 6" up from the
bottom. These are for closed loop circulation. <Where will the returns be from the sump? (Hoses overhanging the tank?)> This will be a reef and small fish tank with live rock as the main filter, plus remote DSB Plus remote
algae refugium. The tank is already built so I need to find the best way to have the overflow/weir (made of glass) built?  I understood that an end to end overflow would be best but just how do I go about this? <Why do you feel this would be the best.  Two corner overflows will be very efficient in a four foot tank.> I hope you can help me as I feel at a loose end at the moment & am not sure how to make this final part of the tank. <One thing about designing the tank is that all this should have been taken into account before the tank was built.  The corner overflows I am referring to below can be cemented in place with aquarium silastic.  It would be very expensive to cut weirs in a four foot piece of glass to do what you are referring to.>
Keep up the great work. I just wish I had more hours in the day to read up some more.
You guys are just great. Thank you. <You're welcome.  James (Salty Dog)>
Simon.

Full length overflow weir question  9/22/05
Hello Crew,
   I hope you are all well and remain that way. <Not bad so far but I've already been on this earth longer than I'm going to stay.>
I spoke to Anthony last time regarding the building of a tank (48x24x24) and I wanted to build an overflow weir at the back of the tank to encompass the two 2" holes cut near the top of the rear glass. I have searched the archives but cannot find the exact dimensions I need to have this weir built. I would like this weir to be end to end and would like to ask a couple of question regarding this, as I have made many mistakes previously and don't wish to do the same again.
    You guys have helped me so much in the past you will never know! Basically I want to know on an end to end overflow/internal weir (made in glass) how deep should it be and how far out from the back of the rear wall should it extend? The two drain holes to the sump are at the top and each end of the tank and are 2" in diameter. I do hope you can advise me as I need this tank  quickly to get some reasonable water flow going. (that's another story)
To all you crew. I just do not know what I would do without you.
<Simon, Simon, Simon.  Why on earth would you want to do that.  A full length weir would require a very large pump to create any usable draw at the weirs to suck in debris etc.  Take a look at this product, it makes more sense to me.  http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=12078&Ntt=overflow&Ntk=All&Ntx=mode+matchallpartial&Np=1&N=2004&Nty=1  You can contact this company as to whether this will work, but I'm pretty sure it will.>  James (Salty Dog)>
Thank you, Thank you, So much.
Sincerely.
Simon.

70 gallon plumbing  9/20/05
Hi Bob!
Do you think that two  3/4 inch bulkhead overflows will be enough to handle the output from a 3100 Rio pump that puts out 900 gal per hour?
<Ah, no>
Do you have any bad advice for making a sump out of Rubbermaid containers?
<... posted on WWM... Bob Fenner>
Thank you for any input!
-Steve Balogh

Overflow, flow, noise...  9/2/05
With a standard (AGA/Oceanic) one inch overflow (on a 90 gallon tank), would it be correct that about 300 gph is all that can be run through that (via a Durso) without the up/down flushing effect?
<This is about it>
I've found my
Panworld 50PX (590 gph max) has to be ball-valved back probably about 50% to keep it quiet.  Wider diameter pipe before and after the hole really can't do much here, right (the Oceanic Durso is already upsized)?
<Correct>
The only answer I assume would be to have a larger hole which isn't going to be an option for me.  Still, heavy in-tank circulation can compensate for this low flow I presume.  Frankly, I'm not sure I'd want a heck of a lot more flow going through the sump.  I appears I'm going to have a hard enough time quieting the water noise from water crashing into the sump?
<Possibly... there are a few approaches here: http://www.wetwebmedia.com/pbnoisefaqs.htm>
Any clever ways to quiet the water flowing and crashing in the sump, other than say sinking the drain line and perhaps having a "T" below the water line in the sump to both smooth out the flow and break the one flow into many?  Like most folks, I'd like to make things as quite as humanly possible.   
<I understand... Please see the link above. Bob Fenner>   

3/4 standpipe on a close loop? 8/24/05
I'm setting up a brand new AGA 75 Bowfront.  It came pre-drilled with a 1 1/4" bulkhead and a 3/4" bulkhead (LFS ordered it that way).  The way my LFS originally told me to set it up was use the 1 1/4 for the standpipe, and the other for the return from my sump.   
<Okay>
I'm running a Mag 12 in the sump to the return.  It is all working just fine.   However, my X10 controls running the powerheads for my wavemaker burned out in just a few days!  After reading on here, clearly I believe a
wavemaker on powerheads is not the right way to go.
<Agreed>
So I've decided to go with a sea swirl connected to my return line from the sump and set up a couple of maxi jet power heads in the tank in addition. So here is the question:
I've thought of getting a bigger return pump and hooking up 2 sea swirls, but I don't think the 1 1/4" has enough flow rate to take advantage of a larger return pump.
<Also agreed>
Am  I crazy to think of taking my 3/4" bulkhead and using that hole as a 3/4 stockman standpipe (I have space for a stockman but not a Durso design)?   
<Won't get you much more... think of the mathematical formula for the surface area of a circle... pi R squared...>
The other alternative is to use the 3/4" as a downspout to a separate smaller pump and set up a close loop with an extra Mag 7 I have and leave the flow to the sump alone.
<A better idea>
  In that case I would connect the smaller pump to a 1/2 sea swirl and the sump return to a 3/4.
<Sounds good>
Of course the final option would be to drain the main tank and then take male and female brushings and create a 1 inch "bulkhead" which would fit in the pre drilled hole.  However, I worry that this would not be a sound
construction.
<Me too>
(I have looked for larger bulkheads that would fit in the pre-drilled hole, but can't find any, the hole is just too small).
<Bingo! Yes>
Any thoughts would be greatly appreciated.
<Your proposed changes are good... that or re-drilling the tank are your easiest options. Bob Fenner>

Re: 3/4 standpipe on a close loop? Bulkhead f'  8/25/05
Thanks, you all are great!  It is always difficult to guess on these things and I know once I set it up is much harder to change.  One quick update:
Decided to do the close loop approach.  
By chance I did find a Schedule 80 threaded coupling where the threads fit in the 1.5" pre-drilled hole but because it is schedule 80 the outer lip is larger then the hole, in fact about the same size as the gasket.  I have
read of some people using threaded fittings in this manner as the bulkhead.
Should I be really worried or is this a safe approach?   
<Can be safe... with securing the bulkhead first... with a smear of Silicone... letting set-up for a day or more... and gingerly (so as not to tear the Silicone) threading a fitting over the outside thread...>
Of course the sane thing to do would be to just use the 3/4 bulkhead, but I'm just not happy with the idea of such a small overflow.  
<Me neither... you would be disappointed I assure you>
I still have a few days before I have to make a final decision (wife is tired of the room where it is being constructed is a mess).
Thanks again.  
<Welcome. Bob Fenner>

Tank flow from Overflow ... not so "reef-ready" tanks 8/11/05
Ok I have read all over your site about micro bubbles and problems of the such, but my problem isn't exactly in that reading and I don't know where else to turn.  I have an Oceanic 75 gal with built in overflow and oceanic
overflow kit.  The line to the 38 gal sump is 1" tubing
<Too small...>
that goes directly into the compartment that contains the skimmer (ASM G1).  There are three baffles, which flow into a refugium and then finally over one last baffle to the return pump (a Mag 9.5) that returns the water through a 3/4" line with a ball valve and then to a T joint to both corners of the tank.  I cannot get a steady flow of water through the line to the sump.  It constantly takes in a lot of water mixed with small air bubbles and at times very large air bubbles.
<... yes>
I called the LFS and they said I should be getting a steady flow through my overflow to my sump with the setup I have with or without the ball valve.
<... no>
I have tried to move the standpipe up and down, add a small piece of air line tubing 3/4 the way down to the sump, and play with the ball valve.
<... won't work>
None of these have worked and I am out of answers.  Is this a common problem or are there any solutions that I am not using.
Thanks
Erik
<Is a very common problem... with most all so-called "reef ready" tanks/kits... the through-puts (holes...) are too small and too few... You need a larger drain line... practically speaking 1 1/2 or two inch inside diameter... two would be better than one... Yes... requiring draining the tank... Please read here:
http://www.wetwebmedia.com/overfloboxfaqs.htm
and the linked files (till you understand) above.
Bob Fenner>

Re: Tank flow from Overflow 8/12/05
Quick follow-up....
If I used the 1" and 3/4" holes in the overflow to feed water into the sump and created a new return line should that do the trick (see below) as far as getting water into the sump at a better rate.  Instead of drilling new holes
or making the current holes larger.
Erik
<Might accommodate adequate flow, would still be noisy... Bob Fenner>

Flow question part 2 8/9/05
OK, sounds good.  I will convert all of the bulkhead holes to drains, my question now is what size pipe do I use for the standpipe?  For the 1" bulkhead I used 1.25" PVC for the standpipe, for the 3/4" bulkhead would I make a standpipe from 1" pipe or 1.25" pipe just like I did for the 1" bulkhead? D'Wayne <Any size that is at least the same size as the bulkhead should do.  The only downside to upsizing is that objects (like snails!) could easily fit into the standpipe, but also easily clog the bulkhead.  Extracting them could be difficult.  Since your standpipes should be protected anyway, this is a minor issue.  Best Regards.  AdamC.>

Drilling Bulkheads - 08/06/05
Dear WWM Crew,
I have decided to get my 30 gallon pre-reef tank drilled and just skip messing with siphon overflows.  (Thanks to reading about all the lovely problems)
<<Excellent!  You'll be much happier for it mate.>>
But I had a few questions.
<<ok>>
First I gathered that tempered glass cannot be drilled but I don't know if my tank is tempered or not.  It is an All-Glass 30 gallon long model (36x12x16) as far as I can gather from the previous owner it was bought new in the mid 90s.  Would you think that this tanks back wall would be tempered?
<<My experience with All-Glass has been that if any, only the bottom pane was/is tempered.  But it's easy enough to contact the company and ask them about this one re the date of manufacture.  I've drilled a few of their tanks (through the sides), both recent and unknown manufacture with no problems (if it is tempered you'll know in a hurry when it "blows out" and scares the bejesus outta ya <G>).  Tanks of recent manufacture should/will be marked if tempered...but then that doesn't help you...>>
If not, I am planning on having (2) 1 3/4" holes drilled to accommodate (2) 1" bulkheads.  I want to have one to each side of the tank and have one drain tee off to a plenum and then connect to the other to feed the sump.  I believe that they should be a minimum of 3" from the top of the tank and 3" from each side.  Is this correct?
<<I just did this very thing for one of my club members...when drilling bulkheads near the edge I recommend placing the outer edge of the holes equidistant from the edge at a distance equal to the diameter of the hole...e.g. - 1 3/4" hole - 1 3/4" spacing, 2 1/2" hole - 2 1/2" spacing, etc...  This will let you get and still maintain strength/integrity of the pane, without guessing at it.>>
I am planning on having between 600-700gph return at first but decided on the larger bulkheads in case I want/need more.  Does this sound okay so far?
<<Problems here I think.  Be cautious of the flow calculators...better to talk to folks/query as you've done here.  The reality is a 1" bulkhead will perform safer, quieter, and with less aggravation/constant fiddling of the plumbing if you only try to push about 300-350 gph per bulkhead.  So...your already maxed out in my opinion.  You'll need to go to a larger bulkhead if you want to turn more water.>>
The tank is for 2 True Percula clowns, Euphyllia glabrescens, Plerogyra sp., Lobophyllia sp., and maybe a Fungia repanda.
<<Ahh...so nice to see you're not going for the usual "reef garden" mix of organisms; you’ll be all the more successful for it>>
Is the flow above reasonable for these species?
<<Yes...be sure to diffuse/spread throughout the tank via multiple outlets.>>
If you have any other thoughts or suggestions please do not hesitate to tell me.
<<Already have <G> >>
I  would rather know now if this setup would work than after I set it up. :)
Best regards,
Andrew        
<<And to you in kind, EricR>>

Re: Drilling Bulkheads - 08/06/05
Dear Eric,
<<Andrew>>
Thanks a lot for your advice, I'll heed it as WWM usually saves me from my own worst ideas.  But I had a few thoughts to run by you.
<<Alrighty>>
If I switched out the 1" bulkheads for some 1.5" bulkheads would this fix my problem of over pumping?  Or, could I make one of the bulkheads a 2" and leave the other as a 1" (the one that tees off to the plenum) and instead of connecting them just run both lines to the sump?
<<A pair of 1 1/2" bulkheads should be fine.  The 1" bulkheads would work, you would just need to size/regulate your return pump (maybe plumb in a gate-valve on the return side) appropriately.  Please have a look through our plumbing FAQs for more on this: http://www.wetwebmedia.com/plumbingmarart.htm>>
Also, I'm not drilling the tank myself but from what you said it is possible to do it yourself?
<<Yes, with the right tools/application.>>
Or would you have a glass company do it?  I have never done it before so I don't know if I want to chance it.
<<First time for everything <G>.  But if you're truly uncomfortable/not handy, it might be best to fine/pay someone else to do it for you.>>
I think that’s everything.
Thanks again,
Andrew
<<Most welcome, EricR>>

Bulkheads And Flow - 08/07/05
Dear Eric,
I promise this is the last time I'll bother you.
<<Hello again Andrew...no bother...really...I'm happy to try to assist.>>
But I was thinking about it and thought that (2) 1.5" bulkheads would/could give me around 1000gph. (Please correct me if I'm wrong)
<<If you're talking about both draining to the sump, then yes, is quite plausible.  Though I must say, that is an awful lot of water to process through a sump on such a small tank (30g)...the slightest restriction is going to put water on the floor in a hurry.  Not to mention the NOISE it is going to make.  I would recommend using one bulkhead to drain to the sump in conjunction with a smaller pump (say a MAG 5), and use the other bulkhead to feed a closed-loop with another MAG 5 or even a MAG 7.>>
I was planning on running a Mag Drive MD9.5.  I calculated that this would give me about 800gph at 4.5' head.  Is that to much to run through a sump?
<<Ah, should read ahead <G>...>>
I wasn't planning on having a large sump, maybe 10-20 gallons and a separate 10 gallon Plenum.  I was planning on running the return into a manifold and was wondering if I should stick with the 1" bulkheads and run a smaller pump and drill a third 1" bulkhead
to run closed loop.  I would only do this if I had no other choice about the sump.
<<Now you're talkin'...  Here's my recommendation for the simplest, most manageable configuration in my opinion.  Have three holes drilled for 1" bulkheads...Use two bulkheads to drain to the sump with a MAG 7 return pump.  Use the third bulkhead to feed a closed loop with another MAG 7 pump.  With head loss due to height/plumbing, you'll have a total flow rate of around 600-700 gph I'm guessing.  By using "two" 1" overflows you will be able to increase the pump size a bit (MAG 9.5) if you determine you need/want the extra flow.  Also...if given the choice...go with the 20 gallon tank for your sump...you need to ensure you will have enough "empty space" to handle the drain-down from the display tank in the advent of a power outage.>>
It will only contain a skimmer, a little mechanical filtration, and a little chemical.  <<and your pumps>>  Will this be overloaded?
<<Assuming you go with the larger of the two sump choices (20g), should be fine.>>
Thanks Again (and again and again...)
Andrew
<<My pleasure my friend, EricR>>