In-tank Manifold 9/23/08 Hey Crew, <Hello Bryan.> In an effort to rid my tank of powerheads that are pretty much horrible for water flow. Could you take a look at the attached jpg and let me know if this would work. My current tank is a AGA 75gal with one over flow, and my sump works fine with a Mag drive 9.5 for the return. However, since I live in the interior of Alaska there is no glassman willing to take a chance at drilling a fish tank. So, since I have an extra Mag drive 9.5, I would like to submerse it in the tank and run a open manifold. The pump would be hid by the rocks and have a fish guard on it. <Functionally this would work fine, the problem you will run into is servicing the pump. Periodically the pump and rotor will need to be cleaned and eventually the pump will need to be replaced. Every time you need to work on the pump it will entail tearing your tank apart. Look for PVC intake screens and put a intake loop into the tank. You will need to prime it the first time out. You can then run the line down to the pump and back up to your manifold. It will basically work in the same manner as a canister filter. If you do want the tank drilled, consider doing it yourself. It is a fairly straightforward process, you basically just grind through the glass. Here is a video of myself drilling to give you an idea: http://www.youtube.com/watch?v=zwc3o_rGmLg.> Using either 1/2 or 3/4 PVC I would like to run 7 directional nozzles. There should be very little head loss since the pump is inside the tank. Is this possible? <Oh yes.> What size PVC should I run 1/2 or 3/4? <For this size pump I would make the loop out of ¾” with 3-4 ½” outputs.> Any comments would be great. Thanks, Bryan <Welcome, have fun, Scott V.>

Re: in- tank Manifold 9/24/08 Scott V., Thanks for the input. <Welcome Bryan.> I did forget to mention this is only temporary i.e. 1 year. I was figuring to have a quick disconnect at the pump head and ensuring I don't place any corals on top of the rock that covers the pump, so I could move just one rock, disconnect and pull the pump for maintenance. <Ahhh, okay, I see!> I want to keep the pump out of the sump so I would not have so much head loss. With the 9.5 I am running right now for the filter with a 3/4 return reduced to two 1/2 nozzles is about all she can handle. I would need more than two nozzles for circulation if I want to get rid of the powerheads, and I don't see that as being possible with the extra 9.5 pump I have. <The same pump will handle 3 half inch outputs on the closed loop you propose.> In a year I should have the addition to my house finished and the new living room will have a in-the-wall 180 or 210 with a utility room behind it. <Nice!> And now that I watched your video (nice background music by the way) I think I'll will get a standard tank and drill the holes myself. <Oh yes, I strongly encourage you to do this, the drilling process is very simple.> Once that’s set up my 75 gal and 36 gal will be tore down and their inhabitants moved to the new tank. Thanks again, Bryan <Welcome, have fun, Scott V.>

Questions On My Closed-Loop System – 03/08/08
To WWM,
<<Hello anonymous seeker of assistance>>
I am setting up a closed-loop system inside my new tank. The tank is a 150gal acrylic size is 60x24x24. I have two 1 ½”?drilled in the bottom tank outside of the overflow box. I have ordered three 1 ½”?strainers. Two of which will be installed in my stand-offs in the overflow boxes. I also ordered a Sequence ReeFlo Snapper pump for this closed-loop system. After further study I now wish I had ordered a Dart model instead.
<<Mmm, yes…for the $30 difference in purchase price, the additional 1200gph would have proven most useful here…especially considering these pumps are rated for low head pressures>>
This pump minus any head pressure is rated at 2400gph. Ok here is were I need your advise/help. I am hoping to add a ‘T’ as soon as I enter tank and reduce fittings down to 1” PVC pipe. I will be making a loop from a 1/3 of the way in on each side of the tank. This loop will start from rear of tank to front (viewing) side back to rear joining back in with inlet ‘T’. I have also ordered enough loc-line tubing to make 6-¾” ports which I will tee-off of.
<Hmm, okay… The ¾” ports, or outlets, will require about 650gph of flow per outlet to be of use (provide a useful force of flow). Using this figure, you need a pump that can deliver 3900gph AFTER headloss. Even if you reduce the outlets to ½” (about 350gph needed per), that still leaves you with a requirement for 2100gph after headloss…and likely still more than the ‘Snapper’ can supply>>
I have decided to place 4 ports in rear and 2 in front. I am hoping this will create a lot of the turbulence I will need for my corals.
<<Sounds fine, but…>>
I also will be burying the 1” lines in sand with only the loc-line coming out of.
<<This too should be okay>>
On the input side I will create a little riser and then use a 1 ½” strainer to protect my wild life. Here are my two questions :
1) Is 6-¾” ports too many with my selected pump?
<<Indeed…as stated. You will likely have to reduce this by half…or go with 5-½” outlets…either of which could still give you good water movement (it’s not always about the “number” of outlets)>>
2) Is having just 1-1½” inlet with 1 strainer on intake going to be rough on my critters or should I also ‘T’ it off inside tank and then use 2 strainers?
<<Most motile critters will know to keep clear…though some “weak” swimmers or soft-bodied sessile organisms may get “sucked-up.” Doubling the intake (with either a Tee or Wye fitting) will reduce the suction at the individual inlets and may prevent possible issues re>>
Please note: critique what I have listed and if any additional current needed in tank will have to come from power heads. Not including approximate 600-800gph thru refuge/sump.
<<With a properly designed closed-loop (i.e. – outlets sized for amount of flow provided), a couple-thousand gph should be fine. Though I would suggest using a larger-than-needed pump with a gate-valve plumbed on the output side to allow some flexibility for expansion and/or eventual loss of flow due to organic buildup within the plumbing>>
Thank you.
<<Happy to assist. EricR>>

Manifold Closed Loop Question, Circulation, des.  12/12/07 Hi All. <Hi Dan> Great site with much good info. The praise never stops! <Thank you.> I have a standard 90g reef tank manufactured by Perfecto. It has a corner overflow with 2 bulkheads at a diameter of 1.25 inch. <Mmm, I'm guessing outside diameter here.> I have a 3 boxed sump/fuge below. First is sump with skimmer (EuroReef RS135), second is return, third is fuge. I have the pvc outlet tube T-d with some of the water diverting to the fuge at a slow rate. The return pump is a Mag 9.5 directly in the return part of the sump. <OK, 950gph at the head.> I seriously need to get more flow, as I have a huge Cyano problem that never goes away. <Yes, that 950 is probably around 800gph in your tank.> I have scoured the site about CL systems. Since the tank is "live", I can't drill any new bulkheads. I don't want any 'U' tubes going over the tank top for fear of leakage. I am thinking that my best option is to get a submersible pump and put it directly in the tank, maybe behind some of the live rocks to conceal it. I am not sure what size PVC I should use for my manifold, nor how many T-s to have for direction of output water, nor what size diameter the T-s should be. I was thinking of just getting some PVC and T-s from Home Depot and making something up. I would like the T-s to be directional. I also don't know what kind or size pump I should get. <With two one inch ID drains you should have the capacity to go with a larger return pump, somewhere around 1200gph. This would give you the flow rate you require. You may consider getting a SCWD (Switching Current Water Director) you can mount to your return line which will give you an alternating current effect. Another way to go is to add a couple of powerheads in your tank. A good match would be two Aquarium Systems 1200 powerheads with a Hydor FLO Rotating Deflector mounted to each. With shipping, you would only have about 65.00 invested. Drs Foster/Smith has the best prices on both items. I use this system and it works quite well.> Much thanks, <You're welcome. James (Salty Dog)> Dan "Salty" not getting it... "<With two one inch ID drains you should have the capacity to go with a> larger return pump, somewhere around 1200gph. This would give you the flow rate you require. You may consider getting a SCWD (Switching Current Water Director) you can mount to your return line which will give you an> alternating current effect. Another way to go is to add a> couple of powerheads in your tank. A good match would be two Aquarium> Systems 1200 powerheads with a Hydor FLO Rotating Deflector mounted to> each. With shipping, you would only have about 65.00 invested. Drs> Foster/Smith has the best prices on both items. I use this system and it> works quite well.>> Much thanks,> <You're welcome. James (Salty Dog)> "> > > I don't think you're getting through to him. Eric< < <James... let's chat re this/our physical universe... have you actually seen/tried to get this much water through 1" ID lines? BobF>> Re: Manifold Closed Loop Question, Circulation, des.  12/12/07 Ok. If I upgrade my Mag 9.5 return pump, what brand(s) would you recommend? <I'd probably go with a Quiet One Model 6000 (1500gph), on sale at Drs. Foster/Smith for 98 bucks.> Can you explain how a SCWD works and how it connects? I am unfamiliar. Brand recommendation? <Go here, will give you a good idea how it works and you can read reviews of users. http://www.marinedepot.com/ps_ViewItem.aspx?idproduct=3Q1111> If I go the powerhead route, where would the best place to mount them be? Opposite corners of the tank? <If you use the Hydor Rotating Deflectors, I'd place a third of the way in on each side of tank. These units spread the flow close to 180 degrees. If not, place the heads in corners. Here is a description of this device. http://www.marinedepot.com/ps_ViewItem~SearchStr~flo%20rotating%20water%20deflector~ action~view~idProduct~HD01401~idCategory~FIWMIW~category~Hydor_FLO_Rotating_Water_Deflector_ Saltwater_Aquarium_Supplies_Wavemakers_Internal~vendor~.html James (Salty Dog)> Dan

Closed loop concerns. RMF Too    7/25/07
Hi, I am setting up an SPS grow tank with an old 75g.
I want to use a closed loop system with five return to the main tank and one feeding a 55g fuge.
<... where will the water be drawn to feed these? Oh, I see this below... Will the pump in the 'fuge be able to keep up with the added water discharged via the closed loop there?>
I will be using a return pump pushing about 3000 gph. My questions are, would I restrict flow if I used 3/4" returns? and, I plan on using two 2" drains from the 75g, would this be enough? Thank you for your help, James.
<The plumbing sizes ought to work out here... but am lost as to your logic for discharge into the fuge. I would NOT add the discharge there... unless this is part of the general circulation pattern... with the refugium higher than the main/display tank, your relying on gravity to return the water to the main tank. BobF>

Re: Closed loop concerns.   8/26/07
Sorry, I should have been more clear. The 55g fuge will be above the 75g grow tank, gravity feeding into the display.
<Ahhh! I see... good>
I will be using a 40 breeder as the sump.
I do not like to combine the sump and refugium, I have found many advantages to placing the fuge above the display.
<Yes... we're in agreement on both>
So the setup will be three tanks stacked on top of each other, the 55g mud filter/refugium on top, then the 75g grow tank in the middle, followed by the 40 breeder on the bottom. I will be using a 400w MH on the 75g and two 150w MH's on the 55g. The pump located in the 40g will push five returns to the 75g and one to the 55g all 3/4". The 55g will drain through a 1 1/2" bulkhead to the 75g, then the whole system will drain via two 2" drains to the 40g.
<Mmmm, these two 2" lines will NOT accommodate 3k gallons of gravity flow per hour... I'd devise some sort of stop-gap/failsafe measure/s here... a third, higher placed overflow of size... perhaps a horizontal "box" arrangement (on the 75)... electronic/water detection switch/solenoid to turn the pump down/off should there be trouble (as in overflow)...>
Any
recommendations would be greatly appreciated, I am writing because I value your opinions, and have learned more than I ever thought possible from your site.
Thank you, James.
<A pleasure to share. BobF>

Closed Loop on 75 Gal.
Hi there crew!
<Afternoon Dave>
My question is about a 75 Gal tank I'm setting up. I plan to have FOWLR, with some soft and LPS corals.
<I think “FOWLR” will shortly be substituted with “Reef” by the sounds…heee!>
I bought the tank used from a guy with SPS corals, and it has been drilled in 5 spots, and is reef ready right rear overflow with two 1" drains). I have a RIO 3100 for a return from the sump (this uses one of the five drilled bulkheads). I also have a GEN X PCX40, and a Coralife external pump both rated around 1000 gph w/ no head loss. I understand that this will be lower as I'm using 3/4" PVC. I've plumbed these using two bulkheads each (one supply, and one return for each pump) I want to run both of these for closed loop pumps, but during my freshwater leak test, I noticed that these pumps "suck" water so hard through their respective feed bulkheads, I'm afraid it'll eat all my livestock. I know I could use an elbow with a strainer, but do you think this is still too much flow without a box (overflow type) in front of the bulkhead?
<This does sound quite an odd set-up. Are all the holes 3/4"? If so then I can only presume that they were all used as returns and non intakes, as you probably realise the intake should be larger than the return. Hmmm.. I would contact the previous owner RE how he had it set-up. It is possible that he had a strainer device coming over the tank to take water to a pump and then returned it through the 4 3/4" using possibly an OceansMotions device. You could go ahead with the configuration you are using and just add strainers but I am presuming they are all base drills (on the bottom of the tank) so this may not be practical. BobF if you could chime in with your thoughts……><<Sounds good. RMF>>
Thank You in advance, Dave.
<Thank you and hope we can find the best solution, would definitely contact the previous owner though, Olly>

How many holes should be drilled in bottom of tank for a CL? Marine System Plumbing...A Need For Understanding - 04/26/07
I am ordering a 180-gal tank from GlassCages.com.  I want to do a closed-loop system similar to Naka's 180 tank on RC.
<<And this is...?>>
I am pretty much a newbie to reef tanks and started my 55-gal in October.
<<Moving up fast, eh?>>
I don't think I understand about the closed-loop system too much except that it could eliminate circulation pumps in the main tank and I want to do that.
<<Indeed>>
Right now I have a 27-gal refugium and a corner-drilled overflow.  Also a plenum and two Maxi-Jets to help circulation in the main tank.  My question is that I need a diagram of how a closed-loop would look and work.
<<Easy enough...have a good look here, and do look/read among the indices in blue at the top of the pages:  http://www.wetwebmedia.com/pbh2oret.htm >>
With the new tank I want to move the 'fuge and/or sump, chiller, skimmer, denitrifier, etc. to the garage and have the plumbing go in the crawl space to the garage about 10 feet away.
<<Ahh, nice...will help dealing with that big and noisy pump you'll need to effectively power the closed-loop>>
I just don't understand how many holes I should have drilled in the bottom of the tank to accomplish this and good circulation?
Which of the holes are drains and which outlets?
<<...?  You don't need to drill holes in the bottom of your tank to install a closed-loop mate.  Please refer to the diagram at the link provided>>
I'm not going to use sand in my new tank. How does one keep any livestock from getting caught up in the drain outlets?
<<Through the use of bulkhead screens/overflow boxes/etc.>>
Thank you very much for any help you can give me.
Georgia Sumner
<<Georgia...before proceeding any further, I very much recommend you to spend a while reading/learning/comprehending the vast amount of information we have on plumbing marine systems.  Start with this article (http://www.wetwebmedia.com/plumbingmarart.htm), and yes...follow the links in blue at the top of the pages.  I'm here to help...so once you gain a better understanding of what is involved and what you want/need to do, feel free to write back to me to discuss further if you wish.  Regards, Eric Russell>>

Closed-Loop Nightmare...It’s In the Design – 05/03/07
Thank you in advance for your help.
<<I’m happy to assist>>
I'm frustrated and don't know how to proceed.
<<Oh?>>
I have been building a 120-gallon reef tank and have done another fresh water test and can’t seem to fix the problem.  I have a horizontal internal overflow that runs nearly the length of the back of the tank, with 4 1.5 inch drains and 2 1 inch returns.
<<Sounds very nice>>
2 of the 1.5 inch drains go to my sump and refugium.  The other 2 1.5 inch drains come together with a wye to a 2 inch pipe that goes directly to my Reeflo Dart pump and back to a closed-loop manifold.
<<Mmm, I think I know where this is going...>>
The return pipe from the Dart starts off as a 1.5 inch and then is reduced to a 1 inch as it gets near the bulkhead.  From the bulkhead it is reduced again to a 3/4 inch pipe around the tank with 6 1/2 inch returns.
<<Sounds like a good design for the return manifold>>
When I just have the one pump on to my sump and refugium, everything works perfect.  Good flow, quiet, and no tiny air bubbles.  Perfect.
<<Indeed>>
However, when I turn on the Dart pump for the closed-loop, all hell breaks loose.
<<Ah yes>>
LOUD would be an understatement.
<<I’m sure>>
Not the pump, the water flow. (this is in my bedroom, so quiet was the goal)  The water flowing through the gutter guard and over my overflow is like a faucet on high with so much flow going through it.
<<Yep...just what I would expect>>
Since the flow is so high it’s causing lots of bubbles in the overflow with it looks and sound like they are getting sucked down the drain, causing millions of tiny bubbles to come through the returns and every so often it sounds like the pump "stops" for a second, like it cavitates, the water flow stops and then instantly continues.
<<Yes...from all the entrained air>>
This is going to be a Acro tank, so I need the flow, but how can I control/stop the noise and bubbles.
<<I do have a suggestion>>
I've taken this thing apart too many times and almost done with this.  I don’t think I can cut or glue any more PVC.
<<Mmm...but will likely be necessary to rectify>>
Any help would be greatly appreciated.
<<Well Brian as you have noted, the high flow rate caused by the closed-loop being plumbed “through” the overflow is causing a massive rush of water in to the overflow chamber creating an abundance of turbulence and noise...and maybe...is also partly due to the overflow not being sized to handle this much flow.  Since this is a horizontal overflow, the option of using a modified standpipe to quiet things down/reduce bubbles is unlikely unless the design is deep enough to allow such.  That leaves you with plumbing the closed-loop “outside” the overflow chamber.  I think your best option is to drill the tank at some point below the horizontal overflow and install the throughput(s) to feed the pump for the closed-loop...and yes, will probably mean more cutting and solvent welding of PVC pipe>>
Thank you,
Brian
<<Regards, EricR>>

Re: Closed-Loop Nightmare...It’s In the Design – 05/03/07
Thanks Eric for your quick reply.
<<Quite welcome Brian>>
What you are saying makes sense.  However, do you see any other way?
<<Not short of reducing the amount of flow, at least not just "off-hand" I’m afraid (sometimes there’s just nothing like “being there”).  Perhaps a perusal of our plumbing FAQs would prove beneficial.  But if you are adamant about not drilling the tank I would recommend some experimentation with “compact” variations of the Durso or Stockman standpipe designs. Here’s a link to a standpipe modified for use in a siphon overflow box that may be of help: http://www.aquariumlife.net/projects/diy-overflow/74.asp.  The challenge is to raise the internal water level of the overflow such that there is very little drop to create turbulence/bubbles within the box.  Noise may be more difficult to ameliorate as you are pushing/pulling more than 3000 gph through the closed-loop and just the sound of the water “traveling” through the piping may be too much for a bedroom installation...though you could try some of the insulation foam tubes meant to insulate outdoor/under-house water pipes to see if these help muffle the noise.  When I installed my large system in my living room, noise suppression was a major consideration in conjunction with the high water flow requirement...to which I turned to the Tunze Stream pumps for my solution>>
I do not want to drill another hole in my tank; I figured 6 would be enough.
<<Mmm, yes...I suspected this would be your response even as I wrote the earlier suggestion>>
I had it made to order and shipped to me.  There is only 1 local fish store, and they don't do that kind of work.
<<If the tank’s back panel was not tempered after drilling, and you are a bit handy, it really is not all that difficult to do yourself.  In fact, if there is an aquarium club (fresh/salt/reef/whatever) in your area there’s a good likelihood there is someone in the club who has drilled tanks that may be able/willing to assist you>>
I ran my design past Bob Fenner before I had it custom made and Bob said it sounded like a good design, that’s why I had the CL holes drilled in the overflow.  Here is the original email:
<<I see this...and am certain the advice given was in earnest based on what was understood/perceived at the time.  If Bob has any other (better) suggestions/alternatives, I’m sure he will add them to this post when it is placed on the “Dailies” page.  If I can be of further assistance you know where to find me.  Eric Russell>> <Indeed... the pumping through the proposed lines is greater than I imagined would be employed. RMF>

Setting up flow for a square LPS tank   3/21/07 Hi Crew - <James> Great website, I spend entirely too much time researching in your archives. I apologize in advance for this long email. <No worries. Communicating effectively often takes time> I am setting up a new tank (well, it's been up and running in some capacity for a few months) that will house LPS corals almost exclusively (will also include one Monti. cap., a few mushroom corals and some xenia, for example), and I was hoping for some opinions on a closed loop system. The tank inner dimensions are almost square, at ~31.5"x27"x20" LxWxH, with an internal overflow on one of the 27" sides. Approximately 65-70 gallons in the display tank. I am using a 20 gallon sump with a very small (~5 gallon) refugium. All flow right now is from the return pump - a mag7 if my memory is right (possibly a mag5). So obviously it is very light circulation in the tank. I have attached a very rough sketch of the tank layout, the live rock layout is pretty close to this though. <I see it. Think the arrows on the overflow need to be reversed> The few corals in the tank right now are a frogspawn (new branches showing), pulsing xenia, hairy mushroom (Rhodactis indosinensis?), Montipora capricornis. Future corals are... unknown. We haven't developed a full livestock list yet, although my fiancé is very much drawn to LPS that "wave" in the current. Any suggestions? <Mmm, all posted on WWM. I'd be reading re the "Systems" and "Compatibility" for all listed, considered> Back to the original question -- I would like to set up a closed loop in the system. My goal in this design was to try to replicate the back-and-forth wave motion in the ocean - the kind that "gently" moves you 3 feet back and forth as you snorkel - and also vary the strength of flow across the display to accommodate varied coral species and their preferences. <Okay> My thought was to try to create flow in the tank in a circular pattern, regularly switching the direction of the flow to create some turbulence. This was in part inspired by the January 2007 article by Jake Adams in the Advanced Aquarists Online Magazine. To accomplish this I considered using a device similar to an Oceans Motion (OM) valve, piped to the four corners of the tank in two circuits. If you reference the attached sketch, I show the four outlets. I haven't worked out any details with Paul @ OM yet, but I see two options with his current devices -- 30 seconds of flow in circuit one (counterclockwise), switching rapidly to 30 seconds of flow through circuit two (clockwise). Or, if I pipe two of the four OM ports back to the pump inlet, I could create 15 seconds of flow in circuit one, 15 seconds of rest, 15 seconds of flow through circuit two, 15 seconds of rest, etc. <Yes> What are your thoughts? Is there a more effective way for me to create appropriate flow conditions in the tank? Am I way off base here? Thanks!! Jim <I do think your proposal has merit, and am a fan of such closed loop designs... but don't think there is "that much" to be gained by stopping, reversing flow patterns in such small volumes as this... That the loss of flow during switching isn't worth the benefits of leaving the water going in the one direction. Having spent years on reefs on this planet, I assure you that many of the stocks folks keep in such "garden arrangements" live in "one way flow" settings... I myself would set up the plumbing arrangement as you illustrate and pretty much leave the water discharges fixed in their orientation, "blowing" basically a angles to each other, two more toward mid-depth, the opposing two more at the surface. Bob Fenner>

Closed-Loop Manifold Design Review (Anthony Calfo) – 03/06/07
Dear Anthony / WWM crew,
<<EricR here...I’m afraid Antoine has moved on to other enterprises and no longer fields queries here...but hopefully I can be of assistance to you...>>
I’m in the process of setting up a 45-gallon tank that is 24”X24” and 18” high.  I have a center back overflow, which due to a miscommunication now only has a 1” drain and a ¾” return as opposed to a 1.5” drain and ¾” return that I’d hoped for.
<<Mmm, indeed unfortunate...but still a workable configuration>>
This tank is intended for Frogspawn and Candy Cane corals only, so I’m shooting for about 500gph flow through the 1” drain and a 15 gallon sump.
<<Is possible...but I always recommend about 300-350 gph maximum flow through a 1” gravity to simplify plumbing hassles (noise, et al)>>
I’ve narrowed my pump choices to either an Iwaki 20RLXT that will flow 450gph or a Gorman Rupp GRI 510 that will flow 550gph according to Reef Central’s flow calculator.
<<Hmm, not the manufacturer’s stated flow rates...I’ll assume this is the flow rate you have figured based on your plumbing configuration then.  Both are good pumps...with the GRI being “pressure-rated” and this particular Iwaki model not.  I think considering your 1” drain, I would opt for the Iwaki...and do be sure to plumb a gate-valve on the output side of the pump to temper flow as/if necessary>>
The top opening of the tank is 17”X16” and I’m planning to have either 6 or 8 outlets from a ¾” manifold running along the perimeter of the opening.
<<On a separate pump/closed-loop I hope?  Eight outlets from a ¾” manifold will require at least 4800 gph after head-loss (based on 600 gph per outlet to achieve meaningful flow)...and way too much for this tank as well. With the return pumps you have listed, you are limited to “two” ½” nozzles at most...and even then I don’t think the flow from each nozzle will be vigorous>>
a)       Do I have too may outlets?
<<Yes indeed>>
I’m not sure how to balance flow per outlet with number of outlets.  Would I be better off with 4 outlets?
<<Not really...the 1” drain on this tank can not handle the flow required to power a multi-nozzle return manifold.  If your goal is to keep powerheads out of this tank then your best option...in my opinion...is to plumb a separate closed-loop, or go with the two 1/2” nozzles as I previously suggested.  Which, considering your stocking plan, would likely be just fine>>
b)       According to Reef Central’s flow calculator, changing the 90-degree bends to 45-degree bends has an insignificant effect on flow rate!!!???  Doesn’t make sense?
<<Mmm...their calculator also says you can flush 600 gph down that 1” gravity drain [grin].  I guess it depends on your definition of insignificant...but I definitely think easing the turns in the plumbing helps>>
c)       I’m planning on using an Aqua Silencer standpipe and I can’t decide between the 1” version and the 1.5” version with an adapter to fit my 1” bulkhead…
<<These devices generally work better if slightly larger than the plumbing lines...I would use the 1.5” device if it will fit your overflow box>>
d)       Is 550gph too much for my tank given the size and livestock?
<<Not in my opinion>>
Thank you for your help,
Narayan Raja
<<A pleasure to assist.  Eric Russell>>

Re: Closed-Loop Manifold Design Review (Anthony Calfo) – 03/07/07
Thanks Eric!
<<Quite welcome Narayan>>
But I was hoping for at least 3 nozzles, min of 450gph and no powerheads in the tank.
<<I understand...but at this flow rate you will be sorely disappointed with the output from three nozzles>>
I have room to enlarge my drain bulkhead to a 1.25" size, but there is no such thing that I could find in schedule-40 bulkhead fittings unfortunately.  Is there such a thing...?
<<Have a look at USPLASTIC.COM...they do have 1.25” bulkhead fittings>>
Having a second pump and a closed-loop is complicated since my stand will have very little room left after the sump, pump and ballast.
<<I see>>
I forgot to mention one little detail -the 4" DSB which will reduce the tank water volume to 31 gallons + sump and it is for the DSB primarily that I'm concerned about having adequate flow... Sorry.
<<No worries mate...and a valid concern re the DSB.  Perhaps you won’t have a choice about adding a powerhead or two...>>
Thank You,
Narayan Raja
<<Always welcome.  EricR>>

Return Manifold and Pump Size? - 03/03/07
Hello to all and thanks in advance,
<<Howdy…and you’re welcome>>
In an effort to rid me tank of annoying power heads and lower temps I am building a closed-loop water return manifold in my 55 gal tank (48”l x 12”w x 20”h).
<<Ok>>
The tank is un-drilled so until I move out of this limiting apartment and upgrade I am sumpless (I refuse to use an overflow box with J or U tube because I would like my security deposit back when I leave).
<<Hee…indeed!>>
I am building the system out of ¾ in. PVC tubing and fittings, and going down to ½ in. at the 45 degree elbows coming out of the T’s.  There will be 10 outlets (4 on the front and back and 1 on each side) with at least 3 or 4 of these being plugged up to allow for changes in flow when needed later on.
<<Ah…good idea>>
The pump is either going to be directly behind the tank for ‘0’ head or on the floor below with 53 in. of head pressure needed.
1- I am trying to find out what size pump would be needed for something like this.  I am thinking in the 1200 to 1500 GPH range.
<<Figure “at least” 250 gph per ½” nozzle, plus another 20% for the eventual bio-film buildup in the manifold piping and this means you need a pump that will provide a minimum of 1800gph “after” head-loss (This is assuming only six of the ten nozzles will be open at any one time…otherwise calculate as necessary)>>
2- Do you think this will be adequate or overkill?
<<Will need to be a bit more in my opinion.  But do be sure to plumb a “gate-valve” on the output side of the pump to temper flow if needed>>
The tank houses 4 damsels and a blue spotted sharp nose puffer (I know he is not reef safe but he is oh so cute and has yet to even looked twice at any of the corals  <<yet>>), various inverts and some corals (whose numbers seem to be increasing…ahh the addiction)
3- Also in purchasing the pump should I be purchasing one rated for pressure or one for free flowing circulation?
<<I would consider a pressure-rated pump for the closed-loop…though a “large enough” non pressure-rated pump will work>>
I am looking at the Japanese Iwaki pumps for more than one reason, choices are:  the MD40RLXT which is a circulating pump rated at 1,200 GPH, and either the MD55RLT for pressure rated at 1,080 GPH or MD70RLT – 1,500 GPH.  What do you think of these choices?
<<All great pumps but…  The 70RLT should work if you’re willing to cap off a one or two more nozzles than originally planned, but I think you would be better off getting the 100RLT for your planned configuration>>
4- Considering heat transfer and electrical usage do you think it is worth my time to also be looking at MAG drive pumps?
<<The Japanese motored Iwaki pumps are fairly economical to run and also surprisingly cool in my experience and would be my preference here>>  
I won’t be having any other pumps running except the MAG – 3 drive that is on my AquaC Remora Pro protein skimmer.  I would rather not be paying an arm and leg each month to run the tank, but I also don’t want to make soup of my tank with super high temps, especially come summer time.
<<Understood.  Don’t discount the effectiveness of evaporative cooling…install a couple fans to blow across the surface of the tank to help keep water temperatures down>>
Once again thank you,
Randy
<<Happy to share.  EricR>>

Plumbing/closed loop question   2/6/07
Thank you in advance for your input.  I've been reading this site for weeks straight and I have learned a great deal, along with a pounding headache
<I don't like this>
and a little more confusion. Every expert gives a little bit of a twist on the same ideas based on their preferences.
<Oh, a matter of your selecting the "wheat from chaff"...>
I'm getting ready to order my new tank. it will be a 125 gal 4x2x2 tank with mostly SPS corals. I keep debating on the size and number of overflows.
<Mmm, likely 2, likely of 1 1/2" nominal ID>
I wanting 20x at minimum flow (2500 gph) in the tank by way of returns from sump and closed loop.
<Maybe three then...>
I do not want any powerheads in the tank like my 70g.  I also do not want to make the mistake of not putting the correct number or size of overflows in the tank.  I'm leaning towards the vertical califlo overflows at the top. My 2nd major issue is that due to lack of floor space, this tank will be in my bedroom, so I need to keep noise to a minimum.
<Then avoid the verticals...>
I was thinking 4 1.5" drains.  3 going to the sump and one going directly to a pump for the closed loop.
<More than one... I'd make this two/three and two to the sump>
For my returns having drilled 2 1 inch returns.  One from the pump in the sump split into two and one to tie into the closed loop.
<... I would NOT tie these together. Run them back independently>
Am I on the right path?
<Nope... how will the water know which way to go?>
I haven't drilled the tank yet, so any configuration is possible, just looking for the best in your opinion.
<Is posted on WWM>
From what I've read it seems that one pump inside the sump and external pump for the closed loop seem to be the most popular, or would you recommend to external pumps, remembering the low noise is key for the bedroom.
<I like external pumps of good quality... less money to run, less waste heat... and better ones are quite quiet>
One of my concerns is that even a verily large pump like the MD55RLT Japanese Motored Iwaki Water Pump  only pumps 1080 gph with a 4ft head. Assuming 1/2 outlets on closed loop needing approx 300 gph each that would only be approx 3 openings when i need more like 6 or 8.
<Then...>
  How in the heck can I get enough water flow without going to a monster of a pump which would surely be very loud for a bedroom.  Also, if I go with a larger pump, wouldn't i need a larger than a 1.5 inch bulkhead?
<I would not... perhaps two pumps of this size... Or settling on the one...>
Any help would be greatly appreciated.
Thanks again,
Brian
<Bob Fenner>

Re: plumbing/closed loop question  2/7/07
Well Mr. Fenner, thank you for the quick response, but I think the pounding headache had the best of me when I typed some of the info.  I had it in my head, it just came out wrong.  Sorry
<No worries... am/was just concerned re your health>
I meant to saw califlo horizontal overflow, not vertical, running across the top/back, which would provide more surface skimming and less noise.  Is that better?
<Mmm, noise-wise, clarity-wise, yes>
Also, i misstated the returns, I wasn't planning on tying the sump and closed loop together.  Let me clarify.
<Please do>
I'm looking at 4 1.5 inch drains drilled into the tank inside the internal horizontal overflow.  Two of the drains to go to the sump and have one pump return it to the 1 one inch bulkhead in that same horizontal overflow and then use your standard loc line to disperse into tank.  The other 2 1.5 inch drains coming out of the horizontal overflow being T together and going directly to a pump and back to the closed loop.
Does this sound any better?  
<Ah, yes. Much>
Also on the closed loop return, do you suggest coming over the back of the tank or could a drill another 1" bulkhead into that same internal horizontal overflow box and start my closed loop from there.
<Mmm, well... if you're already drilling... I'd make these through-puts rather than over-the-top lines. Bob Fenner>

Using A Manifold With An Eheim Canister Filter 1/10/07
Hi crew!
<Hello Laura.>
I read through the info on the Goodbye Powerheads article and was wondering if this manifold idea would work if I built it and ran it out from the return on my Eheim 2028 canister filter (rather than having to add another pump to my already crowded 55 gal. reef tank).  What do you think?
<Laura, the Eheim pump that is incorporated into the filter will more than likely not develop enough pressure to use a manifold with it.  The Eheims usually come with a spray bar option, and this is what I would use.>
And also, does this manifold really allow a tank to flourish without the use of all these powerheads?
<It does help to eliminate dead spots in the system, and yes, can take the place of several powerheads if the pump is sized correctly.  Do search our site on this subject for more info.>
I will admit I am a bit skeptical, but I'd love to give it a try if I can eliminate them!
Thanks so much for this wonderful site and your expert advice!
<You're welcome, and thank you for writing us.  James (Salty Dog)>
Laura

Closed-Loop Or Not? – 01/03/07
Greetings to all, and a Happy New Year.
<<Howdy Bill...Happy New Year>>
After a long delay, I finally have my new tank and stand in position.
<<Neat!>>
It is an All Glass 180 gallon with the Mega Flow system.
<<A misnomer if there ever was one...>>
When all is done it will be a Reef tank.
<<cool>>
I used a Dremel, and cut out the 'teeth' on the overflows, and siliconed black plastic gutter guard in its place.  Converted the drain pipes to Dursos and upped the returns to 1” instead of 3/4".
<<All good>>
My 'plan' it so use 2 pumps for the returns, with one pump running for 5 to 6 hours, then the other coming on for the same duration creating a left then right flow.
<<Interesting...and possibly a long enough interval so as to not greatly foreshorten the life of the pumps>>
I'm at a stand still in my plumbing process though--my questions are--do I want to add a closed-loop, or hang a Tunze in the middle of the back, pointing towards the front.
<<Mmm...the closed-loop will offer greater flow options...but the quality, efficiency, and ease of installation of the Tunze is hard to ignore>>
If I do a closed-loop, I'm thinking of placing it on the tank bottom with the outlets sticking up just out of the substrate--which would be best in your opinion ??
<<Can’t say I’ve ever seen/heard of this but the idea of it is intriguing.  Assumably the force/flow of water would prevent any blockages from occurring...just be sure to install the manifold and pump as a “true closed-loop” (will require drilling the tank) to preclude draining the tank empty in the event of a power outage.  As to which is best (Tunze or closed-loop) that will depend on the needs/particulars of your tank, the size/location of the closed-loop pump vs. the Tunze pump, and your sense of aesthetics.  Using my own situation as an example...I was unable to employ a pump with enough flow to run a closed-loop for my tank (375g...predominantly Acroporids) and still stand to be in the same room (in-wall design...no basement/fish room), so I opted for the Tunze Stream pumps to get the volume of flow I was looking for yet still be able to hold a conversation without yelling, watch the telly, etc.  An added bonus is the power savings...the Tunze pumps really are power misers.  The downside is the “look” of these rather large pumps in the tank>>
I have searched your site and can't find what seems to be the preferred circulation  method.
<<Ah yes, all a matter of opinion, likes/dislikes...not exactly comparing apples to apples here.  My “preferred” method (the Tunze pumps) may not be the same for the next person.>>
Once I get this figured out, I'll place my order for my Live Rock, and begin the cycling process.  I have my RO/DI set up and running, 100gpd, and it is being stored in 2 96-gallon Rubbermaid trash cans, one feeding the other.  The tank will drain into a 40-gallon breeder, that will be the refugium, and that will gravity drain into the sump, my old 90-gallon Cichlid tank, (these are in the basement, behind the wall where the display tank is).
I also have my lighting ready to go when needed too.  What are your thoughts ???
<<The description sounds fine.  I especially like the refugium draining via gravity to the sump (is what mine does), but be sure to have this drain directly to the return pump chamber to preclude excessive loss of beneficial organisms to the skimmer (you “will” employ a skimmer I hope).  As for going with a closed-loop or the Tunze pump...that decision is yours.  Both methods can/do work well with proper application/design/placement.  Is one better than the other?  Not really...they both have their place...more often than not it comes down to what is the most practical...in my humble opinion>>
Thanking you in advance for your time,
Bill Fletcher
<<A pleasure to share.  Eric Russell>>

Closed-Loop Confusion (Maybe Just Me...ER) – 11/27/06
Hello crew,
<<Hello Brandon>>
I have read the works of Anthony Calfo posted on WetWebMedia and have found them very enlightening.
<<Indeed>>
They have inspired me to throw out my power heads and go for a closed-loop water flow system using an "exterior" pump.
<<Cool!>>
I have a question or two (or four) that I wanted to direct to you, I hope you do not mind.
<<Not a bit...shoot>>
To run my water flow system in my 55 Gallon, I will be using a Mag 9.5 pump located in the sump.  Since my overflow box will not support that high of water output (I flooded my living room the first time I tried) I have decided to run it in a closed system.
<<For my own clarification...do you mean you will use the MAG 9.5 pump for the closed-loop, and a smaller pump for the sump?>>
I will be running 3/4" PVC pipe from the main tank to the refuge which will hold the 9.5 and then pump it up 3/4" tubing back up to the tank.
<<Things are still a bit muddy here...first you mention a sump, and now you mention a refugium...is the refugium a separate vessel from the sump?
I am following Anthony's example on setting up PVC pipe at the top of the tank with 5-8 output points (3 on the front 2 on each side and maybe 2-3 in the back for further expansion.)
<<This is too many “outlets” for the size pump you will be using.  To assure adequate “velocity” at the nozzles, you should figure one ½” nozzle for every 250 gph of flow, or one ¾” nozzle for every 350 gph of flow...calculating the usable flow after head loss.  With the MAG 9.5, I’m guessing you’ll only have enough flow for two or three 1/2” nozzles, “maybe” two 3/4” nozzles.  It’s my opinion you will need a bigger pump>>
My questions to you are this:
1) Will a 9.5 pump be able to produce enough flow to these 5-8 output points?
<<Not even close>>
2) Would the system still work if I ran 2 PVC tubes down each back corner of the tank with an output?  I figure this would eliminate any dead spots and give me some laminar flow around the aquascaping.
<<About all you can expect with this pump>>
3) Should I scale down the fittings at each point from 3/4" to 1/2" to create greater pressure?
<<This will help...but you will still only be able to utilize three nozzles at most on the return manifold>>
Or do I run the risk of creating too much back pressure for the 9.5 and risk ruining the pump?
<<Not at all.  These magnetic pumps are designed to work/function fine with backpressure.  Just be aware the MagDrive pumps are not “pressure rated” and will lose flow-rate with increased back pressure>>
4) What do you suggest that I cover the uptake tube with to prevent any livestock from being sucked away to a fast death but that will not limit the uptake water flow? (Again remember that I can not run the pump off the sump water due to the slow rate of flow in the overflow box.)
<<The screens used for bulkhead fittings work nicely here>>
I am "new" to plumbing so I am feeling this out as I go along.  Any suggestions or help would be a great help.
<<Do make sure you are comfortable with/understand the hydrodynamics of a closed-loop before proceeding (write back for further clarification/explanation if need be)...and use my recommendations for sizing your pump/pipe/number of nozzles>>
Have a great Holiday weekend,
Brandon Gray
<<And to you in kind.  Eric Russell>>

Closed-Loop Manifold Design - 03/06/06
Hi-
<<Hello>>
I'm researching my first Aquarium (will be reef with an emphasis on SPS, LPS and Clams and eventually a few fish).
<<Okay>>
I find WetWebMedia invaluable.  
<<Thanks...me too!>>
I'm pretty settled on a 90 gallon tank and a 22 gallon sump with about 110 lb. of LR and a 4 inch oolithic <<or maybe oolitic>> sand bed.
Would like to shoot for 14-15 times water flow and have definitely decided on the Water Return Manifold shown in Anthony Calfo's article.
<<Ahh...excellent>>
I am a bit confused however, and hope you can straighten me out.
<<Uh oh...be careful what you ask for <grin>.>>
The article states "...we need a dedicated supply of water here. Obey the manufacturer's recommendations for line size."  Is Anthony referring to the pump manufacturer's recommendations for line size?
<<Yes>>
Would that be different from the pump outlet size?
<<Unless otherwise stated by the manufacturer, you are usually safe to match your pipe size the inlet/outlet sizes.>>
I am considering using an Iwaki MD70RLT and the outlet is  one inch.
<<Matching pipe to outlet size is fine for these pumps.>>
I like his ideas for finessing the flow with valves and nozzles, especially since my reef will change significantly as the corals grow.
<<Indeed>>
He  mentions using "Flexible Ball-Socket Joint Tubing."  and that it can be connected to PVC.  Is that Loc Line?  
<<Yep>>
Anthony goes on to write "home aquariums of a couple of hundred  gallons or less will likely use 1" or 3/4" pipe".
<<Mmm...or even 1/2" to maximize water velocity.>>
Loc-Line's largest parts are 3/4 inch and there are no T connectors available in 3/4 inch.  There are plenty of valves and Nozzles available in 3/4.  So what I'm really asking is can a Iwaki MD70RLT with a 1" outlet be used to deliver water to my tank though 3/4" Loc-Line hose and can the hose be T-d with PVC?
<<Yes it can.  Likely you will need to bush the outlets down to 3/4" (or even 1/2") anyway to provide enough water velocity.>>
And most importantly will it do the necessary job.
<<Yes...if you have done all your homework and configured it correctly <G>.>>
Thank you for your patience.
Ed
<<A pleasure to assist Ed.  Regards, EricR>>

Return Manifolds/Horizontal Overflow...Closed-Loop Design - 07/30/06
WWM crew,
<<Hello John>>
Thank you for the wonderful website and wonderful dedication to this hobby/passion!
<<A collective effort...quite welcome>>
I am researching designs for a new tank.  From reading Mr. Calfo's Book of Coral Propagation and WWM, I very much like Mr. Calfo's ideas of a return manifold and an internal horizontal overflow.
<<Ah, yes...am familiar with this design>>
Maybe I am just dense, anyway I am having difficultly visualizing how the two techniques would work together along the back wall of the aquarium.
<<Well, let's see if I can help>>
Would one just not have return nozzles on the back wall, if so it seems as if this would make the goal of random turbulent water flow more difficult? Could you please enlighten me?
<<Mmm...the nozzles can be wherever you want them.  No need to follow Antoine’s example to the letter.  You can position a couple nozzles at each back corner and; using ell fittings that are "not" cemented on, swivel these as needed to direct flow.  And do keep in mind here...using a return manifold in this manner (fed through the sump with a gravity overflow), you will very likely not be able to push enough water to drive more than a couple/few nozzles with any real velocity.  In my opinion, the return manifold is better suited to a closed-loop installation if the desire is for vigorous random-turbulent flow>>
Also I was wondering your thoughts on connecting a SCWD to two halves of a manifold return (i.e.- the manifold would not be a single closed-loop; it would be two halves).
<<Is doable.  But re my previous comment, this is not truly a "closed-loop" system if you are using the gravity overflow/sump in-line with the manifold>>
I was thinking that this might assist in creating a wave/surge action in the tank.
<<Possibly...if this is a rather small tank and you use a pump that maximizes the SCWD's capacity>>
One FAQ seem to suggest that the single closed-loop would be better with or without a SCWD.  Your thoughts?
<<A "continuous" single loop would render the SCWD a moot point as all the nozzles would still be in play, the SCWD would only be changing the direction from which the water enters the loop>>
Finally, I am researching tanks and manufacturers.  If I implement the above ideas, I will need to have the back wall of the tank drilled (not the floor obviously).
<<For Anthony's full-length weir design, yes>>
I can not seem to find any manufacturers who will drill the back wall.
<<Hmm...may have to resort to a "custom" builder>>
Does this have to be a custom job at a glass company or a DIY job for those of brave heart?  Suggestions?
<<Maybe order the tank through your LFS and have "them" customize it for you.  Another thought is to go to the hobby forums (e.g.- RC, reefs.org) and post a query there re tank manufacturers willing to drill the back of the tank>>
Thank you!
John Bullard
<<Quite welcome.  Eric Russell>>

Closed-Loop Design/Stocking a 120 FOWLR - 09/22/06
Eric,
Randy here again.
<<Hey Randy!>>
Well,  I'm making progress on the 120 FOWLR project w/55 fuge/sump and have a few more questions.
<<Okay>>
I read on WWM almost every night and get lots of info, but unsure on a few things.
<<Let's see if I can help "clear things up">>   
First, regarding my 120.  I went ahead and had it drilled with 4  1-1/2" bulkheads.
<<Excellent>>
2  1-1/2's will feed my 55 sump/fuge.  I plan on using a MAG 9.5 that I have for the return w/4-5" of head.  Does the 9.5 sound like it will be enough for the sump flow (before you say I need more flow, please read further about my closed loop flow)?  
<<No worries my friend...will be fine as the "return" pump>>   
Second, this is where I need your help.  BTW: I have read a lot on the closed-loops and Anthony's article on the closed-loop.  I see that there are many different ways.
<<Indeed>>
My plan for the closed-loop is: The other 2  1-1/2" bulkheads I plan to "T" together and run into my Iwaki WMD30RXLT.  It will be mounted so it will only have 1 or 2' of head.
<<Ok>>  
-From the 1" output on the Iwaki, what is best?  
  -Should I run it into one closed-loop above the tank that will have 6 to 8  1" overhead "T's" with 3/4" flex?
  -Should I run it into one dead-end loop (I know, then it's not a loop) above the tank that will have 6 to 8  1" overhead "T's" with 3/4" flex?
  -Should I run either a closed-loop or a dead end perimeter with 6-8 outputs?
  -Should the above tank manifold be 3/4" or 1" with the Iwaki 30RXLT pump?  
  -Is the Iwaki WMD30RXLT a good choice and fit for this loop idea?
  -Is there a better design idea with my 2  1-1/2" for the loop flow?
<<Okay Randy, the first option is best/the most simple but I think I need to make something clear here.  The size a and number of "outlets" on the closed-loop determine the size of the pump required...and vise-versa>>  With 6 to 8 3/4" outlets you will need a pump with a terminal output after head loss of at least 4,800 gallons per hour to produce enough "velocity" at each outlet to be useful.  Even if you reduce the outlet size to 1/2" you will still need about 2,800 gph.  With the pump you have now, you're looking at a closed-loop with a maximum of "two" 1/2" outlets (three "might" work, but I don't think you have "quite" enough flow re).  You need to figure about 350 gph per 1/2" nozzle/outlet, and 650-700 gph per 3/4" nozzle.  With two 1 1/2" bulkheads installed, you have the option of using two smaller pumps and plumbing separate closed-loops to each half of the tank>>
And last, I'm thinking ahead about stocking.  Here are my thoughts and ideas I have also read some on this as of lately at WWM.  I will have about 100-120 lbs of LR in there.  Also, I have a 4.5" reef safe wrasse that I will add first.  He is in my 46 reef now.  I don't know what type he is but he is light green completely with several pinkish lines running horizontally across his face and body, all the way thru his tail.
<<Do have a look through our articles on wrasse...especially the genus Halichoeres>>
I want to add shrimp to the reef tank but they will be lunch with him around.
<<Not necessarily, depends much on the species/individual personalities.  I have several wrasse species in my reef that cohabitate quite well with my cleaner and blood shrimp.  One thing to keep in mind when adding shrimp to "any" reef tank is to not just "drop them in" as you do food items but rather gently "place" them low in the rockwork where they can find refuge>>  
I would like a large angel.  Is there one that I can sustain long term in the 4'x2'x2'  120 tank? (please say yes, I love the angels but have limited wall space).  I am thinking of the Annularis, French, Koran??  I need something beautiful, hardy and obviously, not to large.  Any thoughts.  Can you suggest one?  Price is almost, a main concern besides longevity (Inland Chicago area).   I know, I'm not asking for much!   
<<The Pomacanthus annularis would be a fine choice...the other two get too large for this tank in my opinion>>
I would like to add with the angel of choice, a dwarf flame angel, a yellow-eye Kole tang, a yellow tang, a sailfin tang or convict tang (I think that these are all different genera??).
<<Mmm, three different genera (Ctenochaetus, Zebrasoma, and Acanthurus)...the yellow and sailfin tangs are of the same genera>>
Should I only go with one tang?
<<Exclude the sailfin altogether (gets too large here)...I think you could get by with a Kole tang and a Yellow tang...or the Convict tang on its own>>   
A Foxface, and a butterfly (I don't know much about them, what do you recommend?)
<<Several good choices, check out this article for best picks: http://www.wetwebmedia.com/BFsBestWrst.htm>>
Can I add one or two tomato clowns or maroons clowns?
<<Mmm, maybe...but pretty much "full-up" mate.  You need consider adult sizes of the fishes already selected>>
I like the dogfaces but I read that they can emit a toxin??
<<Indeed...but again, your pushing/exceeding limits here>>
I think the triggers are too aggressive, maybe a clown trigger??
<<Only of you want this to ultimately be the only macro-organism in this tank...  There are trigger species that would be suitable, but your past adding any of these at this point>>
I don't want to stock it to the limit.
<<Is about what you've done>>
You kind of see the direction that I am going, what do you recommend?
<<Have stated re>>
Also, I know that the tangs and the Foxface pose a threat, but I would like to be able to stick my arm in the tank if needed without to much concern.
<<Have both in my tank...remain vigilant and you won't have a problem>>
I know that the Foxface will usually hide unless cornered.
<<Will become "accustomed", even curious to your presence...but not likely to be an aggressive/overt threat>>
No eels, lions, poisonous puffers! etc. etc etc...
<<Hee!  No room for them!>>
Thanks yet again for your time, help and devotion to our hobby.
<<Is my pleasure to share>>
WWM has become a one-stop-shopping reference tool for me, I love this site!  INFO, INFO, INFO!!!
Thanks,
Randy
<<Be chatting my friend.  EricR>>

Closed-Loop Design – 10/16/06
Hi Bob,
<<EricR here today>>
I have a 72x28x18 reef tank, planning to keep SPS.  Was thinking of having a closed-loop system with a Dart Supreme 3600 gal/hr.
<<Sounds good>>
What are your suggestions for the plumbing?  I mean , where do you think I should position the outlet and the inlets?  I was thinking of having the inlet at the back panel, about 1/3 the way from the bottom and the outlets at the sides of the tank, with one of them slightly lower than the other !!  I will appreciate your opinion.
Thank you,
Ramy
<<This could work fine, or you could fashion a return “manifold” for the outlets.  Check out this article by Anthony Calfo re (http://www.wetwebmedia.com/pbh2oret.htm) and be sure to read among the linked files at the top of the page.  Regards, EricR>>