Treated CPVC BAD?  Justin Explains the Difference Between CPVC & PVC and Other Acronyms 10/23/05
<Paul> 
In the freshwater hobby I've used CPVC extensively. I've read that in CPVC the C stands for chlorinated and this has raised havoc for the livestock in reef systems.
<Mmmm not that I have ever heard PVC is poly vinyl chloride but is an inert substance that doesn’t leech back into systems. CPVC is used in conjunction with copper tubing and as such is set up with its measured diameters being the outside rather than PVC which is inside diameter. The extra C at the beginning is just the way to differentiate between them. I have used CPVC and PVC extensively for a very long time with no side effects in SW systems.> 
I also have misgivings about the gray PVC and more importantly at this time, The PVC marked DW. This stands for drain water. I've been told that it has antimicrobials mixed in its makeup. Is this true? 
<A few calls to plumber friends in the PVC business, and a company who sells PVC styles have yielded no information of that kind. I have used standard PVC pipe at up to 8 inch diameter before and seen no mention of such agents put on before hand, though PVC is toxic when it is being mixed.> 
The DW PVC is the only 4" or greater diameter piping I have found. 
<Standard PVC comes in at least up to 8” here, try calling a home improvement store or a local plumbing contractors store who carries larger piping etc for such needs.> I really need them for Skimmer and filtration component parts. I guess it boils down to; which of the types of PVC do you specifically have experience with and are there any types you would consider unsafe for reef aquarium use?
Thanks for your time
Paul
<Well PVC and CPVC are fine for usage as long as you let the glue and primer cure for a while before hooking it up. I have run it as soon as the glue is hard (around 1 minute) without waiting in emergencies, but a 12 hour wait guarantees the bond at the joint is as strong as possible before you subject it to pressure. In most setups simple PVC is fine, though CPVC is nice as it takes up a little less space; however, you do loss some flow and add a bit more pressure for the pump to overcome. Buy the same sized pipe that your pump uses without needing adapters or flow restricting couplers from one size to another. The longer the run at one size the easier it is on the pump and the longer your system runs without maintenance.>
<Justin (Jager)> 

Stainless steel clamps 10/19/05
Hi Crew!
<Howdy Steve, Ali here...>
Sorry, I just sent an email regarding a different question and meant to include this one.
<No worries...>
I have a 215 gallon tank with a large wet/dry underneath.  Most of the plumbing is located under the main tank, in between it and the wet/dry below.  The installers (LFS technicians) routed the plumbing very neatly and efficiently, however they used metal clamps around the fittings and clear tubing.  They appear to be stainless and just barely above any water level, however because we have a cabinet enclosing the wet/dry, there is quite a bit of humidity and most everything is constantly wet.  Could this be a problem?
<Yes.>
Please advise because I do not want to be poisoning my fish and live rocks with metals leaching into the water as the metal clamps corrode. Your comments are greatly appreciated. Regards, Steven
<Yikes Steven! It's safe to say that you should avoid any type of metal clamps on your pump connections. Granted, the stainless steel pumps will last a bit longer in a saltwater environment versus other metal clamps, however even they will still rust. Definitely not a good thing. There is also a chance that your clamps may be Zinc or Aluminum plated - this definitely a big 'no no'. I'd suggest you remove the clamps ASAP and opt for either a few strong zip-ties or plastic hose clamps. Give me a buzz down at M.D. and I'll set you up with a pack of them. Dedicate an hour or so during the next couple of days to getting under your tank and swapping those metal clamps out. I know messing around with your plumbing can be a tedious task at times, however it's important you get in there immediately and be proactive. Talk to you soon Steven, Adios! - Ali A.>

Can't Sleep!!! Having a hard time understanding aquarium plumbing... reducing noise  10/19/05
Clear Day, Hi guys...and girls! First I wanted to say thanks for the time and effort you put into this amazing site. There are none better than this! I did a search on your site and there is a lot of information on it regarding my issue but I can't wrap my little mind around it!
I have just finished building up a 90 gallon All-Glass Tank which is pre-drilled by the manufacturer (they say it is 1" and 3/4 but oddly enough mine is 1 1/4 and 3/4(?!) and I also installed the drain/return kit made by them. The top of the drain pipe is curved and has a small hole drilled in the top of it to quiet the noise.
<And expedite flow>
I have a Mag 12 return pump.
<... too large, much flow for this size, number (one) fitting>
I have the 1 1/4 drain line extended to 6 inches below the sump water level with the hope that I would avoid the crashing waterfall sound. Well, it worked!!!!! The problem is it still sounds like an extremely loud brook and the water from the drain line is FULL of bubbles. The noise is making my family nuts because it is in the living room and the bubbles concern me (They are filtered out by a prefilter sponge so none get into the return but they burst at the top of the water and are making a real mess!). Wifey says if I don't tone down the noise I am going to be doing some diving in my tank without a snorkel!
<Mmm, I do hope you enjoy diving>
I read about putting a piece of pipe or an airline in the drainpipe but I don't understand where or how? Is this what I need to do?
<Unfortunately... there is more to this... you need a larger diameter overflow... two would be better... 1 1/2" I.D.... 2 2" would be better... necessitating taking the tank down... re-drilling... or you can get/use a smaller pump... aspirate the 1 1/4" line>
If so, can you draw me a picture!!!!! (or explain it to me in a way that someone who should
have been in bed long ago understands!) Thanks in advance for your time and help.
He who shall soon be drowned in his own tank!
<... this is all posted on WWM... Please read here: http://wetwebmedia.com/pbnoisefaqs.htm
and the linked files above... Perhaps having a local marine aquarium "guru" come by would help... Bob Fenner>

Mathematical calculations 10/18/05
Hey guys, 
<Evan>
I have spent the better part of the last several days on this website drinking in all the information that it has to offer. As a rookie, walking into Borders and finding CMA and later finding this site, I feel that I am off to a very good start. Thank you. 
For the last couple of days I have been dreaming of my ultimate system and reading all the FAQs re the plumbing and refugiums. I have to tell you, I love the mechanical/engineering end of this hobby. Plus I am impatiently waiting for my 55 to do it's cycling thing.
What I want to know is this. Are there any mathematical (ugh) equations regarding flow rates. Everything I am reading is, "your sump is too small, your pipe/overflow is too small, your pump is to big(!)." I am looking for equations that will tell me how much water a 1in overflow will flow, or a 2in or 1 1/4. Would two 1in overflows flow the same amount as a 2. Also, how much sump area/volume would be needed for a given flow rated pump. Or how much water is in transit should the power go out so I know what size to make my refugium. Please nothing that requires a graphing calculator or an advanced mathematics degree. I am more than willing to figure these things out myself I just need to be pointed in the right direction. Judging from all the FAQ's, a lot of other people might find this information useful as well.
One other thing. When does NMA come out? I just learned of it's existence yesterday and immediately went to amazon.com and marinedepot.com, but it is not there. 
<Evan, go to www.reefcentral.com In the left column as you scroll down, there are several calculators available that deal with what you are looking for. James (Salty Dog)> 

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> 

Plumbing  10/5/05
Hi Bob, Anthony, James or whoever is in the hot seat today!
<Howdy>
Hope you are all well.  I could do with a little of your collective wisdom regarding my new system design & my confusion (do you ever feel there is just TOO MUCH information (usually contradictory) out there?)
<Nope... but do find my species too gullible, not discerning enough...>
I have spent weeks pouring over the relevant pages on WWM (every time my boss is out of the office in addition to most evenings (hounded by cries of neglect from my better half!) - I've said it before but many thanks for your dedication and commitment.
<Welcome>
I'm in the process of planning & designing a new 24" cube aquarium (20" tall)- about 50 US gal, in the cabinet underneath I plan on having 2 sumps - first one (fed from main tank overflow) to fit my skimmer in (small Rubbermaid or such) which overflows into the second sump (glass) which will be of the ecosystem design (miracle mud & algae) (sized to their specifications as far as the mud bed goes) - 22"Lx14"Hx10"W) - then returned to main tank
The tank will have lots of LR, thin sand substrate (½ ") & will be reef - mainly soft corals I think but I want to leave lots of options open (I'm positive this tank will evolve!)
Lighting will probably be 4 x 55watt PC lighting. MH may be an option but I already have ½ the lights on my current tank (2x 55w PC) which will be transferred - would I really be much better off with MH? Cost/benefit?
<Not IMO>
I understand from the Miracle mud people that I need to flow 10 x tank volume through the MM sump & I want over 10x tank vol. circulation/flow in the main tank
<Okay>
10x tank vol. = 500gph - this strikes me as too much to return to main tank & overflow back down to sump (for a small tank like this).
<Me too... I don't like much more than 3-4 times turnover in biological sumps>
I am planning to add a closed loop system to augment flow & circulation in the main tank so what I figured was to take the pipe from the sump return pump, add a Tee & divert some back to the start of the MM sump to achieve the required flow rate & aim to deliver a lower flow rate back to the main tank - i.e. maybe 300 gph up to main tank & overflowed back + 200gph looped from MM sump return chamber back into the first (submerged bioball) chamber of MM sump - to give the 500gph.
What are your thoughts on the need for 500gph throughput in the MM sump? will the mud and algae not get blown all over by this high flow rate?
<I think this might happen, yes>
Would less be just as efficient bearing in mind the large quantity of LR in the tank?
<Yes>
The closed loop will be added later (but I know I will need to fit the bulkheads & some pipe work now to avoid needing to tear down the tank to fit later - in the meantime there will be 2 powerheads in there for flow (600 litres per hour each) what size pipe would be appropriate here for the closed loop in & out?
Does all this sound like a sensible approach or too complex or have I lost it??!!?
<Should work>
Or should I just aim to move all 500gph from the main tank - to sump & back without the flow from return end of sump to input end? I would need to either change the emergency overflow to another Durso or add another bulkhead with Durso to do this I think?
What I think I want is a centre back overflow box in the main tank with -
<Mmm, if using this/these, I'd have two>
1 x drilled bulkhead for Durso style standpipe - for overflow into skimmer (SeaClown) box below
1 x drilled bulkhead for higher plain emergency overflow (in case of blockage of the Durso - intake maybe 1"-2" above Durso)
       - or possibly fitted as Durso overflow #2
1 x drilled bulkhead for sump return pump
2 x drilled bulkheads for in & out closed loop (if required)
Am I right in thinking that a 1" pipe for the overflow (single Durso standpipe) would adequately handle 300 to 500 GPH?
<Not the higher number>
Or would I be better going for a larger overflow? Or converting the "emergency" overflow to a Durso? I guess this depends on your views on the above?
<The larger... 1 1/2">
What size return pipe would I need from the sump - does this depend on the size of the output from the pump? Should these be the same?
<The same as the discharge of the pump>
Any suggestions for pump choice?
<Posted on WWM>
If you have a completely different scheme I would really appreciate any and all guidance here!
<Ditto>
Please also confirm for me if you are talking internal pipe diameters or external
<Int>
- I think we measure differently here in the UK (nothing is ever simple!)
I keep thinking that I'll just stay with my 60 litre self contained tank when I try to think about plumbing!!! - which would be a shame since her indoors has authorized the new tank & has even allocated funds!! ;o)
   Confused and dazed & wanting to get tank & cabinet ordered as soon as poss.! (but I do want to get things as right as I can before ordering)
Cheers
   Chris
<Mmm, sounds/reads like you're about ready... Bob Fenner>

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

SCWD and pump combination part 2 9/8/05
The fitting on the pump is 1" so I used 1" pipe to the SCWD. Then from the SCWD to the tank its 3/4". The amount of elbows from the pump to SCWD is 3. Then from the SCWD to the tank through 3/4" is 4. Coming into the pump is 3 elbows as well. Would this restrict a lot of water? Should I redo it with tubing? Should I buy a bigger pump? Right now its 1000 gph. Thanks Joe  <It sounds like you are using big enough pipe/tubing, but you are using a lot of elbows!  All of those elbows are probably costing you at least 30% of your flow.  You could increase the flow by any of the methods you ask about.  You could find ways to eliminate elbows or increase the size of the pump.  In the long run, eliminating elbows will save you the cost of a larger pump, added electricity and added heat.  I would suggest running 1" flexible line from the pump to the SCWD, with the SCWD mounted at about the level of the top of the tank.  You can then run 3/4" flexible tubing along the rim of the tank right into the water wherever you want.  This will eliminate all of the elbows.  Hope this helps.  AdamC.>

New Reef Tank Plumbing Questions - 09/05/05
Hi Wet Web Media Crew!
<<Hello!>>
I have been a reader for some time now and certainly appreciate all the time and effort that you put forth in providing help to those of us trying to learn.
<<Thank you>>
I am setting up a 55 gallon all glass reef tank.  I will be starting off slow and taking my time so that I do not make many mistakes.
<<Patience will pay off my friend.>>
I am planning on about 75 lbs. of live rock, an orchid Dottyback, yellowtail damsel, pajama cardinal, and perhaps some type of fairy wrasse.
<<Yippee!  No tangs!>>
I will add some coral as I gain experience, although I am not sure what types yet.
<<All good, just be sure to do the research before you buy.>>
I will have a 20 gallon sump in my basement directly beneath the display tank.  It will be setting on an aquarium stand.  I will have a 15 gallon refugium underneath the sump.  I am planning on housing my AquaC Urchin-Pro protein skimmer and heaters in the sump.  I will gravity feed from the sump down to the refugium.  I will then use a return pump to pump back up to the display tank.
<<ok>>
I would also like to use a closed-loop circulation system.
<<Excellent>>
The vertical height from the refugium (where the return pump will be drawing its suction) up to the top of the display tank is 12 feet.  I will be using 2 600 gallon/hour overflow boxes to drain down to the sump with 3/4" piping.
<<Mmm...even with two 3/4" drains per overflow box the most you'll want to try to force down those boxes is about 300 gph each...If you only have one 3/4" drain per box then I'd cut that in half.>>
I am a little confused on pump sizing as far as head and flow requirements.
<<Most manufacturers post flow rates at differing head heights for their pumps.>>
I would like to oversize my pump and use a valve on the discharge with a bypass back to the refugium to take care of the excess flow.
<<Sounds good>>
Do you have any advice on sizing the pumps for the proper head and flow?
<<Use the manufacturers flow rates as a guideline...and go at least one size larger.>>
Also, do you have any advice on reliable pumps that I could use?  I am not too concerned with noise since they will be in my basement.  I appreciate any help you may be able to offer.
<<If you want to go with an external pump the Iwaki line is hard to beat (spend the extra dosh for the Japanese motored units).  If you want to go with a submersible model I would suggest either Eheim or Mag-Drive pumps.>>
Thanks
Doug Eakle
<<Regards, EricR>>

Plumbing a semi aggressive fish only tank  9/3/05
Hi WWM,
I've been reading your site on my pocket pc for months. I find it very informative and interesting even though I don't quite get all of your abbreviations and acronyms.
<Ask away, or put these terms in the search tool on the site...>
I am finally ready to buy my marine tank for a bamboo shark, lion fish, and zebra eel. Here's my question: tank size is 72" x 24" x 30" tall 224 gallon U.K. (is this too tall by the way??).
<Not too tall, but not wide enough... you want something at least twice the length of the shark as an adult... in width>
The guy in LFS says a single overflow containing a 1.5" stand pipe for flow into the sump will be sufficient, (to me this sounds a little small, would I be able to get nearly 900g of water through this per hour?
<Mmm, not likely... for a system of this size, shape, I'd have at least two 2" through-puts>
and what about the noise, wouldn't it be loud?)
<Likely so>
what effect does increasing the stand pipe diameter to 2" have - would it reduce noise and increase flow?
<Yes>
what would you recommend in terms of number of stand pipes and size. Would they all be in the same overflow? is there a preferential position for the overflow?
<Keep reading>
Also he says he doesn't use the Durso design for stand pipes, just an open tube (but it does have a control valve for the water rate). Will this alone be as effective as the Durso design in controlling noise in particular?
<... keep reading>
For the return system he has also recommended two Eheim 1260 submersible pumps each with 3/4" flexible hosing all the way back from sump to tank (sump is directly under the tank by the way). if I remember correctly, flexible hosing is good for noise reduction but has a lot of internal resistance. given that each pump is rated at 502gph minus 25% approx for losses will give a total turnover of 753phr. is this sufficient/correct turnover??
<Not for the life you list>
regards
Lex of London U.K.
<Keep studying Lex... you're not ready. Bob Fenner>

SCWD and pump combination 9/2/05
I bought a SCWD and a quiet one 3000 pump for my 55 gallon tank hoping to remove powerheads that cause heat. After plumbing everything the water flow wasn't enough. The head height is about 5' from the pump to tank. There are a ton of elbows which I think are causing the water flow problem. I returned the pump and got the quiet one 4000 which is 300 gph more. Still I don't think this is enough water flow. I have no idea how to plumb this without using so many elbows. Is there a different way to achieve better water flow using this pump and wavemaker? Thanks Joe  <A couple of options come to mind.  First is flexible tubing.  This should allow you to eliminate most of the elbows.  Just be sure to use hose clamps
Also be sure that you are using large enough pipe/tubing.  For a pump that size, you should be using at least 3/4" of not 1" plumbing to minimize resistance to flow.  Hope this helps.  AdamC.>

"Y" Must I Use a "T"? - 08/18/05
Crew,
<<Tim>>
I've been reading through the plumbing FAQs but I can't seem to find what I'm looking for.
<<ok>>
I have a Dolphin 2100 pump for my new (still not fully assembled) 135G reef.  I have the tank filled with freshwater for a plumbing test.
<<good idea>>
The 1 1/2 inch discharge from the pump goes vertically through a coupling, a shut off (ball) valve, to a 1 1/2 Tee. Each side of the tee goes horizontally to each side of the tank then through an elbow, a 1 1/2 to 1" reducer, a 1" bulkhead, and a manifold up in the tank.
<<ok>>
I didn’t really want a Tee to split the flow.  It seems like I'll loose a lot of head that way.
<<Some, yes.>>
I wanted more like a Y, but I can't seem to find Y's.  The closest I have seen is a sanitary tee, or a three way Y that I could use if I plugged the center port.
<<Yep...pretty much your choices.  There are some symmetrical polycarbonate "Y" fittings used in wood-shop central vacuum/filtration systems...but I've never explored to see if these would be suitable/safe for cementing to PVC.>>
What is the best way to split the output of a pump two ways???  Is my Tee as good as it gets?  I cant seem to Google the right phrase to find suggestions.
<<Your question is not uncommon, many hobbyists; myself included, have wrestled with this option.  Due to it's uneven/unequal design, the sanitary-T gives unequal flow...and I feel the 3-way lends itself to too much internal turbulence with a high-pressure pump, thus reducing flow.  In the end, I've found the best, simplest, and cleanest way is to go with a standard "T" fitting.>>
Thanks (again),
Tim
<<Regards, EricR>>

Plumbing Design - 08/11/05
Hello Crew!  
<<Howdy>>
Thank you for the great advice so far.  My tank is (oh so slowly) progressing toward the day it will actually have saltwater in it!
<<agonizing, ain't it <G> >>
I have a 180G.  I am not sure how large my sump will be yet, but I plan to do a separate refugium.
<<Goodonya mate!  Is really the best way to do it, as opposed to combining the two...in my opinion.>>
It will be fed water from a tee off the sump return line (already skimmed), controlled with a gate valve.
<<This can/will work, though I prefer to feed raw tank water to a 'fuge.  Nutrient export is part of the function of a refugium, after all...and the critters you're trying to cultivate will appreciate as well the organic matter that is going to be removed by the skimmer.>>
You can see a diagram of my plumbing plans here: http://home.cfl.rr.com/homebrewed/fish/sump_plumb2.jpg
<<Nice diagram, but you're making it more complex than it needs to be; and trust me, the more simple your plumbing the happier you're gonna be in the long term.  This will work...but I think you're going to have to "fiddle" with it constantly.  Not to mention I think you'll have a "noise" issue as well.  If you wish to discuss, let me know and we'll chat more.>>
I want the fuge to have a DSB, some live rock, and lots 'o macro algae.
<<Mmm...which macro algae?...may want to exclude the rock from the 'fuge in favor of the increased water flow.>>
I'd like the fuge to provide food (small critters) to the main tank.
<<Most desirable/beneficial, yes.>>
My main question - I am trying to decide on an external return pump size and would like to know how many times turnover you recommend for a refugium?  If I were to use a 20G refugium, would 400 GPH be way too much?  Should I plan on only 200 GPH?
<<200 will probably do, but 400 is fine if the plumbing is set up to (effectively) handle it.  I would go for the higher number and throttle back as/if necessary.>>
Thanks,
Randy
<<Regards, EricR>>

Turboflotor/Eheim 1260 question... mis-plumbing, how-to destroy pumps 8/4/05
WWM Crew,
First off I wanted to say that you were right, my Ocean Runner pump started behaving erratically only two weeks after I hooked it up. As per your advice I purchased an Eheim 1260 to hook up to the Turboflotor system. I am having a few problems with the system though. First the bubbles produced from the Eheim pump seem to be larger and do not foam as nicely into the cup.
I've tried adjusting both the knobs on the skimmer and the air intake. The way I have it setup is a tee before the intake of the pump,
<Not good... these centrifugal pumps are designed to push, not pull... I would re-do your plumbing to place the restriction in front of the Eheim discharge>
one side going to the sump water and the other to air with a valve.
<The air likewise should be after the discharge, and after the valve>
I also have a tee installed in the discharge of the pump, one side going into the skimmer and the other back to the sump with a valve so I can control how much water goes into the TurboFlotor. The second problem I am having is that the Eheim pump seems to produce a cyclical output. The water/foam level in the skimmer cup will go up and down about a 1/2''-1'' every second or so, as well as the air intake tube produces a slurping sound on the same cycle basis. The intake of the pump, intake tee, and air intake tube are all 1''. Any suggestions you could provide would be greatly appreciated.
Thanks,
Cory
<... this pump... is suffering from air cavitating about its impeller... this is the slurping cyclicity... Bob Fenner>

Re: TurboFlotor/Eheim 1260 question... actually, a Venturi question 8/5/05
Bob,
I went ahead and moved the tee to just after my pump discharge as you suggested. The air line began to spray water out,
<... you need to understand the "basics" of how Venturis, valving work...>
and I decided that the line was too big to allow air to be pulled into the stream. So I put a 1/4'' line in the side of the tee instead, with basically the same results. If I blow down the air line it will create some bubbles for a few seconds afterwards then stop. Am I missing something in the installation of the air line.
<Evidently so>
Basically it is just a tee from the plumbing section of the hardware store that has a piece of flexible tubing in the side perpendicular to the flow of the water.
<Uhh, no... there is a difference in pressure needed as well... Maybe take a look at a "store bought" engineered Venturi system. Bob Fenner>
Thanks,
Cory

Plumbing suggestions? 7/21/05
Greetings Bob and crew...
<Sam>
Suffice it to say that you guys have been quite helpful in the past, and continue to provide an incredibly valuable service to the hobby.  Thank you.
<Welcome>
I'm getting really tantalizingly close to being ready for live rock (happy dreams of LR critters poking around), and just have this one, last plumbing issue before all of my ducks are in a row.  Would like to see if I'm on the right track.
<Sure>
Here's what I've got.  125 gal tank.  1" drain,
<Only one?>
with a Durso standpipe.  The drain hits a T which routes water to the sump for processing, and also splits water to the refugium, which gravity feeds back into the sump.
Return water is pushed back to the tank via an Iwaki 30RLT, which is linked to a SCWD, returning water alternately to two 3/4 inch returns.  All plumbing via vinyl tubing.  Limiting factors as I see them are the 1" bulkhead on the drain, and the 3/4 inch connections on the SCWD, necessitating 3/4 inch returns.  Additional current via a PanWorld 50 PX-X (1100gph) feeding a closed loop.  
<I do wish... you had two 1 1/2" drains, two 1" returns...>
Here's what's happening.  With about four extra inches of water in the sump to prime the system, I'm able to raise the water level enough that water is returning via the drain.  However, even as the water is returning from the tank, the pump is pulling enough water that the sump level is falling below the pump intake, resulting in lots of cavitation.
<Trouble... drain lines too small, sump too little water for transit volume>
  Looking at the 1" drain tubing, its not draining at the full capacity of the tubing, which is the same diameter as the opening in the bulkhead.
<... a common misperception... the line doesn't "suck" water out of the tank... water has to "pile up" higher... drain>
My first thought was that the pump was pushing more water than the drain was capable of handling.
<In a manner of speaking, yes>
I now am not convinced that this is the case.
Considering the SCWD, the 90-degree fitting on the openings of the 3/4 inch returns (and the spring activated check valve) I've got something like 9 feet of head according to Reef Central.
<The model there is necessarily a simplification>
  Looking at the spec.s on the 30RLT, with that much head pressure, I shouldn't even be approaching 600gph, which I believe is somewhere in the area of the max capacity of the 1' bulkhead.
<Uh... no... there are a few very important (co)factors involved... the vinyl tubing has some induced drag, the extent of the horizontal run from the bulkhead...>
I'd considered slipping a gate/ball valve on the output of the return pump, but really don't think that's the answer.
<It is not>
  Perhaps I need a slightly larger hole in the cap of the standpipe?  Or perhaps just adding a few more gallons of water in the sump for the pump to prime the system?
<No my friend... the root of the problem here is really the lack of size, number of through-puts... you won't be able to get enough water through what you have>
This is my first foray into plumbing an admittedly rather intricate system, and as such, would be interested in any suggestions you could provide.  Am also curious if there might have been value in hard plumbing the system,
<Yes... in some cases, some flexible is a good idea... but in most... rigid is preferable... for how many reasons?>
as it seems like there might not have been as many issues utilizing straight lines and angles.  I assume that that the other side of that sword is that with the vinyl tubing, I likely have less head pressure than a similar set up using elbows.
Thanks in advance,
Sam King
<Sam, do read over the Plumbing materials we have archived on WWM... there's a bunch. And do have some other folks with similar systems chat with you re yours... I would have the tank drilled for two 1 1/2" bulkheads (two inch diameter) and use the existing through-puts for returns. Bob Fenner... who has "been t/here, done this... many, many times>

Re: Water Return Manifold 7/20/05
Dear Mr. Fenner,
    Thank you for your advice.  But speaking about water returns I was reading through a lot of messages on WWM and saw a large number of messages that complained of sump overflows during power failures.
<Mmm, real overflow "boxes" take account for such failures... they don't lose siphon>
  Since I also live in an area where we experience frequent power outages (rural Montana) I had to find a cure for all the spilled water.
<... principally adequate (large) size/d transit volume sumps... not filled to capacity...>
Since I use an older 30 gallon
glass tank, drilling was out of the question.  So I use the dreaded J-tube as my sump intake but instead of letting gravity do all the work my intake is connected to a Quiet One 1200 pump.  It pulls the water into the sump but shuts off during a power outage.
<Mmmm, I would NOT do this... far more trouble to be had...>
And with a small hole drilled in the J-tube slightly below the display's water surface it eliminates back siphoning.
<What if this becomes occluded...?>
The sump's output is also connected to a Quiet One 1200 that (was) returning through a spray bar with a hole drilled below the surface.
So I can leave my sump almost completely full and not worry.
<... no...>
  By utilizing 2 identical pumps I found a cure for my woes.  Plus there is very little adjustment needed since they both pump the same amount.
<Almost laughable... but, "you'll learn"... Have seen, read about such arrangements... many times over the years... they eventually fail, flood floors>>
  I just thought I would try to provide a little info and some feedback to you guys for others to whom drilling is out of the question.
<My emphatic message to all others who read this: DON'T try it>
  Though, there is some caution to this tale.  I don't recommend it for the lax reef keeper (If there really can be such a thing) Because the pumps must be cleaned religiously in order to keep them both working in prime order.  If only one stops...it can be potentially disastrous unless you use a very short intake tube.  (I know that from experience... )
Best Regards,
Andrew
<You'll see... Bob Fenner>

Re: Water Return Manifold 7/20/05
I agree very much with Bob... to the extent that I have repeated darn near a mantra on such matters that I would rather have no sump at all than use any kind of siphon overflow. Put another way, I don't want to sleep in a house that has a siphon overflow. As Bob says... they WILL fail in time. And beyond flood, there is fire hazard at times. I have seen this on one occasion thanks to a siphon overflow.
Don't do it mate. The downstream features are not that badly needed nor so difficult to plumb upstream [the display may be inconvenient to drill... but a refugium or reservoir next to and slightly above your tank can be drilled to hold refugium life, skimmer, Ca reactor... anything that you would have fed with a siphon overflow)
Please(!) reconsider. Anthony
<Thanks for this Antoine... thought you might want to see, respond to this ongoing corr. BobF>

Re: Water Return Manifold 7/21/05
Dear Mr. Fenner,
Please forgive me for even causing you to post this on WWM.
<Mmm, no worries... we post most all.>
  I have only had the system running for 2.5 months and haven't had a problem yet.  I had no idea that it could actually pose a risk of disaster.
<Oh yes...>
  I am relatively new to the hobby and the only thing that had been recommended to me was a J-tube setup by an aquarium store which I no longer shop at. I didn't know about putting the sump above the display.
<Is generally safer... if practical to situate it so>
Anthony mentioned this, and I would like to know how it is done.
<... is posted... in places on WWM, our latest book...>
  If you could briefly explain it that would be much appreciated.  Also, please don't post the letter if it may lead others into believing it will work.
<Not to worry... You've likely saved a few lawsuits, broken marriages... and more...>
  I would hate to cause someone else to make a potentially disastrous mistake.
Sincerely,
Andrew
<There are many ways to learn Andrew... direct experience of larger scale mistakes is not a good one. Bob Fenner>

New Setup Advice - 07/19/05
I have just taken delivery of a new 900L tank.
<<Sweet!>>
To be used for salt water fish only.
<<Sweet! (again)>>
I am quite new to this hobby, and have had the specifications given to me by the shop.
<<Um...ok>>
The tank is fitted with a corner overflow, water leaving through a 1" drilled hole into the sump.
<<Ugh...too small...>>
The sump looks rather large to me 36"L X 22"W X 20"H, The outlet flow enters the first stage into around 6" in height of plastic balls with thick wool placed on top.
<<...wet/dry filter tower...>>
The water leaves at the bottom through slots, and enters the second stage which is full of net bags of various substrate.
<<...chemical filtration media...>>>
The water then overflows at the top entering the third and last stage, here we have a Multi SL 1000 skimmer powered by a PH 2500 pump.
<<Skimmer is a bit small for this tank in my opinion.>>
The return pumps intended to be used are two Eheim 1262 rated at 3400L each, one pump flows through the drilled hole next to the inlet in the overflow section, and half way along the top of the tank by pvc pipe.  The second pump flows through Eheim plastic tubing entering from the top of the tank.
<<Unless you have another means of water egress from the tank these two pumps will overwhelm your 1" overflow...in fact one of these pumps will be too much.  You need something that will not push more than about 1200-1400 liters per hour through that single 1" overflow else you're in for trouble my friend.>>
It is also possible I will also be adding a 2500L circulating pump also in the third stage to feed my chiller.
<<Not without adding more/larger overflows to feed that sump you won't.>>
I am curious as to what happens if the power goes off with this type of sump system, I assume the water must keep flowing until it reaches the bottom of the slots in the corner overflow.
<<It will, yes.  You will need to make sure the sump can handle the drainage from the tank in the case of a power outage without overflowing.>>
Will I need extra flow inside the tank in the form of powerheads?.
<<Likely, yes... Shoot for a MINIMUM of 10x tank volume for flow.>>
Your thoughts would be much appreciated.
<<The single 1" drain is killing you here my friend.  You need to rethink your return pumps and/or add more holes for return lines to the sump.  The single 1" drain will serve the sump with an appropriately sized pump, but you will certainly need more flow in the tank via powerheads, closed-loop, etc..  As for the chiller, your best option is probably to use the sump return pump if the flow is within limits for the chiller.  Eric R.>>
Regards

More Setup Advice - 07/21/05
Thanks a lot for your input.
<<Welcome>>
Unfortunately I am now stuck with this setup.
<<Mmm...kinda figured.>>
This morning we fired the tank up, and as you have stated no way will there be enough supply to feed the 2 pumps.  The system is ok with 1 pump in operation meaning I can only pull water from the sump using 1 pump 3400 L or about.
<<Hmm, obviously enough head loss between the sump and the tank for this.>>
Would this mean I can only use powerheads within the main tank to make up the shortfall.
<<Unless you are willing to drill/have someone drill more holes for drains...yes...I'm not one to recommend siphon overflows.>>
Regarding the skimmer being on the small side, as I have a large sump, ok to add a extra skimmer?
<<Definitely.  Some here prefer this to a single large skimmer (one is always functioning while the other is down for maintenance/cleaning, etc.).  You might even consider a skimmer that uses a different method for producing foam (e.g.- spray injection vs. needle-wheel).>>
Or should I upgrade to a larger model?
<<Can do also...though probably the more expensive route.>>
Regarding the filter system do you think it will be enough, or will I require any additional filtration?
<<Your bio-load, presence/lack of live rock, etc., will determine whether or not your filtration system is adequate.  As this will be a "fish-only" system, monitor your water quality and if conditions dictate consider adding a fluidized-bed filter to the mix.  These can be very effective/fast acting for non-reef systems.>>
Thanks for your help and time.
Regards
Alan
<<Happy to assist, Eric R.>>