Plumbing Pumps & Holes   12/14/06
First of all thank you for your time, patience and knowledge. I am planning my tank order and I would like to get it right the first time.
Here goes... 180 glass (72x24x25) Looking for about 15x turnover (3000gph) with the following. Two 1.5 inch drains in the back wall draining into a 75 gal refugium. A mag18 returning over the back with 2 outlets, should be around 1000ghp. Also a 2 inch drain driven by a Dart attached to a closed loop. The loop will be over the top into an inside perimeter manifold with about 4 outlets,
<I'd double this number>
should be around 2000gph. Will a 2 inch drain feed the Dart.
<Mmm, barely... if it were me, mine, I'd also double this number of intakes, join together near the pump intake... for a few reasons... but mostly for the inevitable blockage near, over one of them>
Does this sound  like a good plan for my flow target. Many thanks in advance.
Daryl
<Bob Fenner>

Re: Plumbing Pumps & Holes   12/15/06
Thank you for your time, you/yall are a great asset.  Holes side by side, maybe 6 inches apart?
<Mmm... intakes? At either endish... Please read here: http://www.wetwebmedia.com/plumbingmarart.htm
and, oh yes.... the linked files at top. BobF>

Upgrading after a year    4/4/06
Hello people!!  I've had a 70 gallon saltwater aquarium up and running now for a year and now its time to upgrade.  The plan is for a 72"l by 24"w by 22"d, what is that about, 150 gallons?
<Yes>
For drilling the holes I've decided to drill 5 one and a half inch holes across the back top pane of glass, 2" from the top and 2" from the sides, spread evenly across.  3 will be overflows going to a 50 gallon sump and 2 returns to the display tank.  Does this sound ok so far?
<Yes... but I would make the drain holes two inch... to accommodate 1 1/2" through-put diameter>
The glass is 3/8",bottom piece is 1/2" thick.  Could you tell me what the best size pump to get for this would be (GPH)?
<... posted on WWM>
The sump will be directly below the main display tank if that makes a difference.  Thanks for now for your wisdom!  Steve K
<A bunch more to go over Steve... That you may already know... But do read on WWM re plumbing, through-hulls... Bob Fenner>

Drain Line Confusion  4/29/06
Hello all!
I'm about to have my tank drilled by an LFS and seem to be having a bit of conflict as in the amount of drain lines I need. I had planned on having two 1.5" drains drilled in my 75 gal. but he's trying to get me to only go for 1 2" drain.
<You're better off with the two 1.5">
The holes will be on the back as the bottom is tempered. His reasoning is that the 2" can handle the flow from a 1000 gph pump and less holes means stronger glass.
<A reasonable statement, however, there will be much better circulation afforded by having two distal overflows, and a margin of safety granted should one become occluded...>
This makes sense but at the same time I am worried that the single 2" drain will result in a noise issue. Are my concerns valid?
<Yes... though pi R squared for the surface area of both... The two lines can be about as noisy if not engineered properly>
If I can should I get him to agree that if I do have issues with noise he will drill another hole without me spending more?
<Mmm, up to you, but it's a pain in the keester to take the tank back down and into the shop... if it were me, I'd just have the two holes drilled and be done with it>
(the deal is he'll drill and build an overflow for $125) Looking forward to your response.
Joel F.
<Bob Fenner>

-Sand and bulkheads-  - 5/7/2006
Hello crew!  I have two situations today that I hope you can help me with.
<Certainly>    
  Situation number 1:  I'm starting up (another) new tank, and I am using Nature's Ocean fine sand (not live sand).  I didn't realize it until I had already added it, but I'm supposed to rinse this stuff.  Now the water's all cloudy and full of gunk.  Will this settle in a day or two, or do I need to empty the tank, rinse the sand, and start all over?  I don't have enough salt at the moment to do that, so I'd half to wait a day or two regardless.  Maybe running a filter on it would help?
<The sand "dust" will settle within a day or so, and running an extra filter will help clear up the tank, just check and clean your pumps powerheads etc after it settles to ensure they are not clogged with dust either.>    
  Situation number 2:  I had a tank (yet another) drilled for bulkheads.  One 1.25 drain (was supposed to be 1.5 but they got it wrong) and two 1" returns.  Now I see that all the bulkhead sizes appear to be too big.  One inch seems to mean "inside diameter" and my holes are only 1" so...what can I do?  Do I just have to take this back and get it re-drilled?  It's pretty expensive here (most places charge $30.00/hole).  I'm hoping you know of a place online that sells special small outside diameter bulkheads (remember -- MUST fit through a 1" hole).  
<I do believe that a 1.25" drain is a 3/4" bulkhead fitting.  my slightly bigger All glass aquarium one that came in a kit, was about that size.  If you can, I would look into having the hole redrilled and get the people that did it wrong to redo it if possible.>   
  Thanks bunches guys!  We really appreciate your help out here in cyber-land.
Angelica
<Hope that helped>
<Justin (Jager)>

Bulkhead misery - 05/06/2006
I recently got my 75gal AGA tank back from my LFS after having him install a custom overflow as well as drill the back for a bulkhead. I had told him I wanted a 2" bulkhead and that's what he put down for my order and that is what it says on my receipt. However, upon getting my tank back, whoever drilled it only put a 1" bulkhead on it.
<... bunk>
I was in such a rush at the time I got it, I didn't have a chance to discuss this issue with the guy. Now I am trying to decide if it is worth the effort to get him to fix his problem, or if there is anything that can even be done to 'save' my tank.
<Mmm, can be re-drilled... otherwise refit>
First, I know I have every right to demand (or ask politely, haven't decided how angry I am yet) that he fix his error.
<You are wise to "hash through" w/ yourself, not be angry, emotionally distraught in dealing with this/all matter/s>
I just need to hear someone else tell me it's the right course of acting and is worth all the hassle! Second, is it possible for this overflow to work with my setup which will have a 1190gph pump returning water to the tank.
<Mmm, no... the present through-put will not accommodate this flow>
According to reefcentral.com's head loss calculator I will have appox. 890gph when all is said and done. I know this is cutting it close, but is it better than the alternative of taking it back to get it fixed.
<Not IMO... better to have re-drilled. As important as adequate diameter of this fitting, plumbing is, there is also an/the issue of noise... much easier to correct with bigger...>
I know only having one overflow is a danger in itself, but I thought that having the 2" drain line would reduce the risk significantly and now that it's only 1", my gut is churning. I guess I know that getting it fixed is my only real option here if I want to avoid disaster. This makes my real question what can be done to fix this by the LFS? The overflow is a 3 sided trapezoid on the middle back of the tank with the bulkhead in
the middle of the height of the tank, about 10" up. Could another bulkhead be drilled below/above the existing one so that one acts as a backup?
<Yes...>
Your suggestions that I can take to the LFS would be greatly appreciated. Up until now I loved this particular aquarium store, but now my experience is soured by this episode. Thanks for listening to my tale of misery,
Joel F.
<Mistakes happen Joel... do take this up, patiently with the stores management... asking what they might do, suggest to remedy the situation. You do need more through-put here. Bob Fenner>

Re: Bulkhead Misery, And fluorescent lambda - 05/07/06
Hey Bob,
<<EricR here...Bob's off at another "fishy" event>>
Took the tank back in today after talking with him on the phone. He's just going to redrill and fit a new 2" bulkhead on there.
<<Great to hear>>
He was really apologetic about the whole fiasco.  I'm just glad it was so easy.
<<Indeed... As Bob stated, sometimes best to "cool down" and present in a calm manner>>
On another topic, I am trying to determine what type of lighting would be better for my setup.  I was going to go with 4 x 110watt VHO's with 3 being 10k and one being Actinic, but I've also had reefers suggest T5 HO's.
<<The current "fad"...the VHOs will be just fine>>
The cost for T5's is quite a bit higher from what I've seen and it seems I would also need more like 6-8 T5 bulbs.
<<Agreed...VHO gets my vote/is what I use/have used for years>>
As far as what these will be lighting, I plan on keeping mostly softies and maybe eventually some LPS or SPS and a Tridacna derasa.  Which would be more appropriate for this?
<<Not saying the T5s wouldn't work as well, but I have a good friend who keeps all the critters you mentioned under VHO lighting with great success>>
Thanks again,
Joel F.
<<Regards, Eric Russell>>

Refugium, Pump, and Overflow Sizing - 05/17/06
Hi,
<<Hello!>>
Have been doing much research on reef tanks, mostly on the web and came across your site, what a find, very impressive.
<<Thank you>>
I just bought a 100 gal DAS reef tank.  It's got a single 1-1/2 inch sump drain in a corner.  I wanted to put the large CPR Aquafuge under it and use an external 1000 GPH pump for circulation with a SCWD wavemaker.
<<Mmm, which model Aquafuge?  Unless you're talking about the "Aquafuge Pro" it is too small/not really suited to this application.  It would be better/cheaper to employ a small aquarium (20g/29g) for this>>
My questions are - 1) Is the pump too big for the drain?
<<My opinion?...yes.  Most overflow "calculators" will tell you you can get 1200/1300 gph from a 1.5" drain.  And under "ideal" conditions maybe so...along with lots of noise and continuing fuss.  But tank conditions are rarely ideal...plumbing is not always optimized...and there's the fact the plumbing will slowly become more restricted from mineral/biological buildup.  I think it is much less problematic to "tune" your overflows when you only try to push "half" the rated flow.  That leaves you in this instance with a pump that will push 650 gph or less (after determining/calculating head loss) to the overflow>>
2) Is the refugium big enough?
<<Depends on the model>>
3) Is 1000 GPH too much flow through the refugium & if so how would you control it separately?
<<With a smaller pump...perhaps a Mag-Drive 9.5>>
And lastly;  4) Is the skimmer that comes with the CPR any good?
<<I think you will be disappointed.  I would replace this...look to ASM, AquaC, Euro-Reef, others...>>
Thanks in advance for any help.
<<Very Welcome, EricR>>

Overflow Bulkhead Size? - 05/25/06
Hi,
<<Hello>>
I was wondering if you could shed some light on the subject of the overflow hole size.
<<Sure>>
I recently ordered a 135 gallon glass tank w/overflow.  The drain or overflow is 1" and the return is 1/2".
<<Mmm, typical...and "undersized" in my opinion>>
A local fish "expert" told me that I need to cancel the order and get at least a 2" overflow hole?
<<If possible, I agree>>
Why is this?
<<The larger throughput will make it MUCH less problematic to plumb this tank with regards to noise, maximizing flow, etc.>>
I do not understand why it matters and I already purchased a ProClear Pro Series wet/dry 150.
<<Please read through our marine plumbing article/FAQs, there is much helpful info...you can start here: http://www.wetwebmedia.com/plumbingmarart.htm >>
I thought this was going to be a good set up.  Am I wrong?
<<Can't say for sure, I don't have enough information about your setup or what you plan/want to keep>>
Also, he said the glass tank will not hold up with 2 holes drilled in it?  Confused?
<<...?  If the tank is properly constructed with forethought to hole size/location, multiple throughputs should not be a problem>...perhaps you need consider another tank manufacturer>
I appreciate any info.
Thanks -Dan
<<Regards, EricR>>

Regulating Pump Flow... Inadequate Factory Overflows - 06/12/06
Hi Crew,
<<John>>
I bought an Eheim 1262 to use as the return from my sump to my 90g (with AGA Megaflow).
<<I love Eheim pumps...wish we could get some of the bigger ones over here>>
It's a great pump, but it seems too powerful for the Megaflow system.
<<Not so "Mega-", eh?>>
Actually, I should say it seems too powerful to run the Megaflow quietly - water rushes though the system and it sounds like a dishwasher.
<<Typical of these undersized (Mega or not) factory overflow systems>>
I've read through the FAQs and this seems like a common problem.
<<VERY common>>
One suggestion that helped was to increase the diameter of the hole at the top of the Megaflow drain tube.  However, my system is still extremely noisy, unless I pinch and restrict the flow coming out of the Eheim.
<<Replacing the Megaflow drain tube with a Durso-style standpipe might allow both an increase in flow AND a reduction in noise...but still no replacement for the simple want/need of a larger throughput>>
So my question is (finally) is it safe to add a ball-valve on the return side of the Eheim, or will this produce too much back pressure and jeopardize plumbing connections?
<<This is quite safe and satisfactory, though I would install a gate-valve as opposed to the ball-valve for better "finesse" of the flow.  Magnetic drive pumps such as the Eheim respond to/endure this type of control/adjustment very well.  But do make sure you install the valve on the "output" side of the pump>>
Would it be better to step down to the Eheim 1260 and let it run unrestricted?
<<Not in my opinion.  The plumbing lines will eventually start to restrict from bio/mineral accumulation...but with a twist of the valve you can step up flow to compensate>>
Thanks,
John H.
<<Quite welcome, EricR>>

Optimistic Flow Rates - 07/11/06
First of all great website, I've learned tons and spent hours reading posts, thank you.
<<You're quite welcome...glad you find the site beneficial>>
I tried to find my question but had no luck.
<<Let's see if I can help>>>>
I have a 300 gal FOWLR with a 50 gal sump.  I am running two twin tube hang on the back overflows, both with twin 1" drains.  I read I should be gravity feeding 1200 GPH for each box totaling 2400 GPH to my sump.
<<Read?  Where?  No way on Earth you're gonna get 1200 gph to "gravity flow" through a 1" drain.  1200 gph may be the "rated" flow on the overflow boxes...but it's not going to happen with a single 1" drain>>
My return pump is the Mag 2400.  I want high flow as I have groupers and triggers in this tank.
<<Mmm, yes...most all fish species appreciate good water flow.  Though I'm skeptical when it comes to processing this much water through a sump.  But if the noise, bubbles, splash is not an issue with you...>>
I used 1" for everything.
<<Not big enough>>
Right off the pump I have a check-valve, spring type from Lowes and a ball-valve on top of that all in the return line.
<<The check-valve is not a good idea.  Aside from metal contamination from the spring and the huge lose of flow incurred when using these devices, the valve will inevitably fail at some point...usually when no one is around for a long period.  Much better to adjust your skimmer boxes, return lines, and the water level in the sump to handle all transient water when the power is off.  I'd also like to suggest you replace the ball-valve with a gate-valve...will give you much more "finesse" when flow adjustment is necessary>>
Then it goes up the back of the tank and tee's to the ends when I have a 90 up then a 90 over then a 90 down and a 45 into the tank.
<<Mmm...head pressure indeed.  Between the check-valve and the elbows I doubt your getting little more than half the rated flow of the pump>>
I hope you can picture this.
<<I can>>
The problem is even with all that head pressure from 10 90-degree fittings, the ball-valve and the 45-degree fittings, I can't run the pump at even 50% or the aquarium overflows.
<<Not surprising.  At the "most", I think you should expect 500-600 gph from the 1" drains...about half that if you want a bit of a "safety margin" or to keep things quiet>>
I have to turn the ball-valve closed by almost half way for the tank to not overflow.
<<Indeed>>
Will changing the return plumbing to 2" help fix my problem?
<<Ahh yes!  Will improve things by a huge margin>>
Very confused, and lots of different formulas and theories.
<<Agreed...and most seem a bit "optimistic" to me where flow rates are concerned>>
Please Help.
Thank you,
David
<<I hope I have.  Regards, EricR>>

Optimistic Flow Rates II - 07/11/06
Ok, I was told by US Plastic's that a 1" drain will flow approximately 600GPH.
<<Yes...hear this all the time.  But I can tell you a more practical expectation is about half that.  A 1" drain may indeed be "physically capable" of allowing a gravity flow of 600 gph...getting it to work so in an aquarium application is another matter>>
My overflow boxes have dual 1" drains.  That's where I figured 1200GPH per overflow box.
<<Oh, okay...did not get that from the first email>>
Four 1" drains for a total of 2400 draining to the sump.
<<I see now.  But as you have discovered...not a practical flow rate>>
The bottom of the overflow box has a 1" union going through it.
<<Not a "union", is a "bulkhead"...two different fittings>>
So do I need to try and drill a bigger hole in the bottom of the overflow box to accommodate for a bigger bulkhead or can I just adapt a 2-inch pipe to the 1-inch bulkhead.
<<To increase the flow rate you will need to increase the size of the throughput (bulkhead fitting and drain pipe).  Just adding a larger pipe to the 1" bulkhead won't help, it still leaves you with the smaller restriction at the bulkhead>>
I also have the 1" U tubes.  Do those also need to be bigger?
<<Likely bigger AND more of them.  Actually, you might try this first.  With all the head pressure on your pump, the four 1" drains may well handle the flow and the real problem is your siphon tubes are not keeping up>>
And worst case if I can't drill the bottom of the acrylic box to adapt for a bigger pipe, can I just add another dual-drain overflow box?
<<If there's room...certainly>>
Then not only would I have a plumbing nightmare, but I'd have SIX 1" drains going into my sump.
<<You may want to consider alternative methods for creating flow and assign a smaller pump to service the sump>>
I would like to keep the high flow rate as it seems to make a difference in my other salt tanks.
<<I would agree, but it doesn't all have to be processed through the sump. Not having a drilled tank makes a closed–loop problematic...perhaps some Tunze Stream pumps?>>
I never imagined this to be this complicated.
<<Designing/building the drain system can often be challenging>>
I greatly appreciate the help in your fast response. Thank you
<<Very welcome, EricR>>

New Display-Questions on Bulkheads/Sumps/Filtration - 07/21/06
Dear WWM Crewmember,
<<EricR here...how can I be of service?>>
I have been a freshwater aquarist (125 gallon) for many years and am now taking the leap to marine.
<<The experience will serve you well...but still, much reading/research ahead of you>>
I have researched your excellent site and read through The Conscientious Marine Aquarist.
<<A good start, but don't limit your research to a single source.  Opinions/experience is varied and wide.  Gather your information from varied sources and use your own good judgment to make decisions re>>
I have learned tons but still have a few questions regarding my specific needs.
<<Alrighty>>
I am interested in purchasing a 175 gallon Oceanic bowfront w/ two MegaFlow overflows (rated at 650 gph each, for a total of 1,300 gph).
<<Mmm yes, generally undersized and overrated overflow systems.  For simplicity of plumbing/maintenance, and to ease noise/bubble issues, I would plan on/expect about half the rated flow>>
Although I intend for it to be a FOWLR set-up, I know one day after much experience I may want it to become a reef tank and want to plan accordingly for flow.
<<Yes, best/easiest to plan/plumb at this stage>>
Not to mention I'd also like the flow increased for the FOWLR set-up anyway.
<<Indeed...vigorous water flow benefits fish as well as coral>>
Therefore, when placing my tank order from my LFS I am going to have Oceanic drill larger bulkhead openings.
<<Ah!  You "have" been doing some research!  Excellent my friend>>
It comes standard w/ holes large enough for 1" outlet and 3/4" return inlet.
<<Yes...unfortunately>>
I'm hoping the MegaFlow overflow is large enough for holes sized to accommodate 2" bulkheads.  Do you know if this can fit in their MegaFlow overflow?
<<Mmm, don't know...perhaps you can order these "upsized" as well>>
What about increasing the 3/4" return inlet if it fits within the overflow - should I do this as well?
<<I would, yes (1").  Can always be "necked-down" at the tank if you need more "velocity">>
Any bulkhead size recommendations for this specific overflow would be appreciated.
<<As big as you can go with the current overflow box...or upscale the overflow box>>
On to sump/refugium questions...
<<Okay>>
I am planning on purchasing a 55 gallon capacity sump/refugium from S P Aquatics...
<<No chance of separate vessels for these?  Using a single vessel for both can be/is done by many, but generally one methodology (sump or refugium) or the other suffers, in my opinion.  But I find separating the two eases equipment placement, attenuating flow for each, maximizing space, etc....and greatly simplifies isolating one from the other when/if necessary for maintenance/repair>>
They have two designs (or will customize) and I have no idea which might be best for my set-up.  The "X1" models have the display drain area on one side, water moving through refugium in middle, then water moving to skimmer/return area on the other side. The "X2" models have a display drain/skimmer area on one side, another display drain/refugium area on the opposite side, with both sides flowing water to a middle return area.  Any ideas on which one might be best?
<<I think the "X2" is the better design...less chance for the skimmer to "rob" you of beneficial organisms from the refugium>>
I plan on using a EuroReef CS8-3 skimmer.
<<Ahh, wonderful...I love these skimmers...use a CS12-3 myself>>
Also, in addition to the skimmer, I'll use live rock in both the tank and refugium - should I employ wet/dry filtration in this sump as well?
<<I wouldn't, will consume a lot of space which will already be at a premium as you'll discover.  Obtain and use a fluidized-bed filter...great for FO/FOWLR systems...will ramp-up/adjust quickly with fluctuating bio-loads.  Will also be much easier to "disengage" than a wet-dry when the time comes>>
Your help is much appreciated - thank you.
Martin
<<Happy to assist.  EricR>>

Drain Flow Rate 9/27/06
Howdy guys and gals! Thanks very much for all the help so far!
<Hello Garth>   
My new tank has a corner built in overflow box with a 50mm (2") drain hole drilled in the bottom. with two 32mm (1 1/2") pump pressure returns drilled holes.
The drain return (to the sump) has a bulkhead fitting and due to that it ends up with 40mm (1 1/2") ID PVC pipe and a Durso submerged inlet (all 40mm - 1 1/2")
The pump pressure returns are also bulkhead fittings and end up as a 20mm (3/4") ID after the bulkhead fittings. But with the use of an adaptor I end up with 1" ID for the two pump pressure returns.
I plan on running two Oceanrunner OR2500 rated at 2500l/h each (625gph).
<The OR2500 is rated at 650gph.>
There will be approximately 4ft head  on these two pumps. So I will have a total of 5000l/h (1250 gph).
<With a four foot head on each pump, you will not have 1250gph, but somewhere around 700-750 gph which is well within the drain's capability.>
I would just like to know if my overflow will handle this flow rate.
Thanks for your kind words of wisdom.
<James (Salty Dog)>
All the best and take care.
Garth

Re:  Overflow And Pump Size 9/27/06
Hello again James,
Thank you for the quick response.
<You're welcome.>
In regards to connecting the sterilizer and chiller on the same pump, I had posed this question earlier on WWM. The chiller I have has a flow rate of 250-350 gph and the sterilizer a 100-200gph flow rate. EricR (who responded quickly as well) said that I should use separate pumps for each since trying to adjust proper flow would be difficult. Do you still think I should connect them all together, if not, do you still recommend a return pump of 500gph.
<You gave no flow rates on the equipment in your query to me, so I assumed they were sized for somewhere in the 300-350gph range.>
(I am adding EricR's response so you can see it in total.)
<Should have replied with Eric's suggestions, since he answered your original query and was aware of the equipment being used.  Much better for the same person to do the follow-up.>
I value everyone's opinion at WWM so any suggestion on which method to use will be greatly appreciated. I want to try and avoid  the whole "trial and error" process as much as possible.
<Now knowing the equipment you have, I would go with Eric's suggestion on the UV, and, if it were me, I'd go with a pump in the 400gph range and pump water from the sump, into the chiller, and back to the tank.  With the head pressure loss, you will be around 275-325 gph on the return, well within range of the chiller recommendation.  Additional flow rates can be increased in the tank by use of a powerhead.  This will give you flow in the tank from more than one direction.  Based on Eric and myself's suggestions, you will have to decide which method will work best in your situation.>
Once again thank you in advance.
<James (Salty Dog)>
Wayne

Overflow And Pump Size 9/26/06
Hello,
<Hello Wayne>
I am planning on upgrading my 15 gallon tank to a 35g with a 20g sump. My  tank is not drilled so I'll have to use an overflow to bring water to the sump. What type of overflow do you recommend (gph flow) for this size of tank and what gph pump do you suggest. I am thinking about using a SCWD wavemaker connected from the return pump.
I will be connecting a 9w sterilizer and a 1/10 chiller into the sump as well. Each  will have its own pump because of the differing water flow. The chiller and sterilizer will be pumped from the pumps in the sump back into the sump ( if that makes any sense). Only the return pump will be returning water back to the tank. Is this method of circulation o.k. or should I try it another way. I will have a skimmer, but due to the limited space in the sump it will have to be hung on the back of the tank.
Keep up the good work.
<Wayne, not a very good way to do is.  First off, the chiller will be turning on/off constantly as it will be looking at water already cooled for the most
part.  Same goes for the UV, you want it to look at as much tank water as possible.  I'd select at least a 500gph pump and connect everything in-line.  Pump through the chiller, then the UV, then back to tank.  Multiple pumps in a small system will use more energy and create more heat, and the chiller will run more
often, adding to the bill.  Overflows should be selected so that it's total flow rate is close to the pumps capability.  Oversized overflows create problems in this
regard, often leading to constantly removing air trapped in the "U" tube due to the slower flow rate through the tube.  I'd probably go with the CPR CS-90 overflow,
which will give you a maximum of 600gph flow rate.  This still puts you in between a rock and a hard spot.  The CPR CS-50 is a little shy on flow rate for your tank (300 gph), and the CS-90 is a little high at 600gph.   Your other option is to have the tank drilled, which would be the way I'd go.  It would still be cheaper than buying the overflow and eliminate the hassles of such, and less clutter in/on the tank. The 20 gallon sump would still be fine in this system.>
Thanks in advance.
<You're welcome.  James (Salty Dog)>
Wayne

Overflow Design/Bulkhead Size    10/3/06
Hello.
<<Howdy>>
I have a 135 gallon (6-foot) glass aquarium that is not drilled that I would like to set up as a reef.
<<Ok>>
After doing some reading on your site I'm leaning toward having the tank drilled and building some sort of gravity fed overflow, since siphon "CPR style" overflows seem to eventually fail.
<<Indeed...though I must admit I ran/used siphon overflows for more than a decade with but a few "failures" in that time... and nothing catastrophic as I always allowed for transient water volume in both sump and tank.  There are measures to take to increase reliability...and if using siphon overflows it is always a good idea to use "two".  But if you can drill this tank then I do suggest that is the way to go>>
I like the idea of drilling the holes on the back wall near the top of the tank (2-3" from the top would be ok??) in case a bulkhead leaks not all 135 gallons end up on the floor.
<<Mmm, yes...is my preference over drilling the bottom as well.  As for the holes, the edge of the drilled hole should be located at least the diameter of the hole away from any edge (top or side).  For example...a 1 1/2" bulkhead requires a 2 3/8" hole, thus, the hole should be located so it edges are no closed than 2 3/8" to any tank edge.  This is a bit conservative for some folks, but is a good rule of thumb for maintaining/maximizing strength/integrity of the glass panels>>
I was planning on 2 X 1 1/2" (inside diameter) bulkheads, would this be sufficient for approximately 1,000gph flow from the sump pump?
<<Should be, yes...and why not drill an "extra" bulkhead while you're at it?  This can be capped-off for now but will be available should you decide to add a closed-loop, etc.>>
Is it necessary to attach the internal overflow boxes around the bulkheads or could I just use some sort of basket shaped screen to keep critters from going through the hole?  The screen idea just seems much easier.
<<Indeed it is.  I have my tank drilled through the end walls (is an in-wall installation viewable from front and back).  I used "slip" bulkheads and modified 1 1/2" ABS 90-degree ells (notched edge of top opening) fitted with a short length of PVC pipe and inserted in to the bulkheads to create "mini" overflows.  Another method would be to simply insert bulkhead screens and design the drain plumbing coming from the bulkhead to the sump with a small "hump" just off the bulkhead to control/raise the water height in the tank above that of the bulkhead.  (Have I lost ya yet?)>>
If I did decide to build an overflow box do I have to use glass since nothing seems to permanently bind glass and acrylic?
<<Silicone will usually bind acrylic sufficiently for in-tank overflows>>
Is there anything else I could build it out of that would bind to the glass aquarium that is easy to cut and work with?
<<Give the acrylic/silicone a try...many overflows in manufactured tanks these days are plastic>>
Ok, one last question.  All the overflow boxes I have seen in stores always go from the top of the tank to the very bottom.
<<Generally because these tanks are bottom-drilled>>
I'm assuming this is because they are made for tanks that are drilled at the bottom.
<<Ah, yes!>>
Since I want to drill my tank near the top, can I build a much shorter overflow box, say 5-6 inches tall?
<<Indeed you can, though without support from resting on the bottom of the tank, glass might be a better choice over acrylic for the better "bond" with the silicone>>
What would you recommend as the minimum dimensions of each overflow box to accommodate a 1 1/2" (inside diameter) bulkhead?
<<Hmm, I'd try 5" high x 4" deep x the entire length of the back wall...but do a Google search on our site/the NET re "horizontal overflow" to get other perspectives on this>>
Thank you for all your help,
Jon
<<Happy to assist.  Regards, EricR>>

Re: Overflow Design/Bulkhead Size – 10/03/06
Eric,
<<Jon>>
Hey, thanks for all your help.
<<My pleasure>>
I really like your "mini" overflow idea.
<<Works for me <grin> >>
Is it very loud?
<<Nope>>
I read that many people install the "Durso" standpipes to quiet the water.
<<Tis is true but there are others ways to mitigate noise...reduce flow or increase the number of throughputs for same...aspirate the drain lines...>>
In your "mini" overflow design, I don't think that is possible, is it?
<<Would/is not possible, no>>
Is that a problem?
<<Not in my experience/with my configuration>>
Would two 1 ½-inch diameter elbows acting as the mini overflows be sufficient for a 135 gallon (1000 gph flow)?
<<Can’t say for sure without giving it a try but yes, likely so if you can aspirate the lines well enough to prevent surging/sucking.  But honestly, you don’t need to push this much water through your sump (you will have other means of providing water movement in the tank, yes?).  You can go ahead and use a pump rated at this capacity, but do install a gate-valve on the output side of the pump to allow you to reduce flow if necessary to quiet the overflows/the sound of the water rushing in to the sump>>
Are they screened off in any way of just have notches cut into them?
<<Just notches...and positioned high enough under the lip of the tank (acrylic) to prevent fish/astrea snails from entering.  If this is a concern, you can try rolling a bit of plastic “gutter guard” and inserting this in the ell (will need to be checked/cleaned periodically of any accumulation to prevent loss of flow)>>
Are they glued in or just pushed on?
<<A slip/friction fit>>
Would a thread X thread bulkhead work in this case too?
<<If you have enough clearance above the bulkhead to “spin” the elbow, yes>>
I'd want to be able to remove the elbow in case it needed cleaning or to be replaced, and would rather have it screw on rather than just push in, for safety's sake.
<<The slip fit has not been an problem in my experience, just be sure not to wedge it in so tight you can’t get it back out>>
The bulkhead screen idea seems good too.  Let me make sure I understand it though.
<<Alrighty>>
Inside the aquarium would only be the screen, about 3 inches underwater.
<<Correct>>
On the outside you would simply raise the pipe coming from the bulkhead a few inches up to the point where you want the level in the tank to be, by using a few elbows, right?
<<In theory, yes.  I have not tried this myself>>
Would it be a big deal that you wouldn't be skimming any water off the surface, rather just below?
<<This method doesn’t allow for removal of surface film>>
Ok, I'll leave you alone now.
<<Not a problem my friend>>
Thanks again,
Jon
<<A pleasure to share.  Eric Russell>>

Re2: Overflow Design/Bulkhead Size – 10/03/06
Eric,
<<Hiya Jon!>>
Hey, just wanted to say thanks again for all your help.
<<Truly my pleasure>>
I think you just solved my problem.
Jon
<<Ahh...is redeeming to hear (read).  Good luck with your venture my friend, 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>>

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>

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.>

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>

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> 

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> 

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

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>

Standpipe/Bulkhead Size  2/18/06
Hello, <Hi Gabe>
I asked you guys some questions a couple of days ago but received a puzzling reply that left me without answers. <Sorry, that was my doing.  I could have swore I answered that query.>  I have included the original message and your reply below. I am not sure if this reply means that I should find the answers by searching previously "answered" queries, or that James felt that someone else had already answered this particular query. I am pushed for time on this installation and have already ordered the 2" bulkheads due to space and price.  If you felt as though I did not research this sufficiently I would like to explain myself.
I understand my desired flow requires a drain/bulkhead between 2.26" and 2.61" using the calculator at reefcentral.com (which reference I found at WWM.com). I also found that recommendations made by much of the WWM crew on drain/bulkhead sizes seemed to be higher (many times double) than what the calculator provides (I am not sure, but the calculator may provide an "exact" size without any tolerances). <Believe you are correct here.> I also could not find a query on this subject that had desired flow rates as large as mine. Furthermore, there have been some suggestions to increase standpipe sizes to reduce noise levels, but I have not found whether a grossly oversized drain could increase the noise level. I requested your preference or opinion on bulkhead size due to the noise factor and the vagueness of information presented on sizes vs. flow requirements. I did find sufficient information to promote the vent I was asking about by further searching WWM (shame on me). I do hope I have not offended you guys as it is prudent to have such a knowledgeable group on my side. <Two 2" lines should do the trick.  Some people will go with a Durso Standpipe to help eliminate noise.  You can search/read this subject on the WWM.>
Thanks, <You're welcome and sorry for the mix up.  James (Salty Dog)>
Gabriel

Set Up/Sump/Drain Size  - 03/12/2006
Hi....<Hello Mike.>
Thanks for your time.  Fantastic web site.  "Before"  doing my homework I bought an all-glass 54 gallon corner tank.  I thought that the 1 1'4" predrilled drain would be enough for this tank draining about 600gph but after reading the fine print I found out that in the corner tanks the flow is only 400gph.  I'm considering using the predrilled 3/4" return hole as another drain and plumbing the return over the top of the tank.  I'm just not sure if the two different sized drains will be a problem and if the skimmer box will be able to handle this additional flow of water without backing up. Any quick thoughts would be appreciated.  <Mike, the 1 1/4 drain is more than enough for a 600 gph flow.  Don't know where the "fine print" came from.  James (Salty Dog)> <<James, after the diameter of the bulkhead is considered, the inside diameter of this through-put will likely be less than an inch... RMF>>
Thanks for your time  <You're welcome.>
Mike