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Related Articles: Plumbing Marine Systems, Myth of the One Inch Beast (Why Relying on One Inch Overflows... or Overflow! Is foolhardy) by Scott Vallembois, Plumbing Return Manifolds, Refugiums

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Complete, vigorous circulation...

Fluctuating Sump Level; one inch drain line/s      11/9/14
Dear WetWebMedia,
Thank you so much for your service to the aquarium trade. I have successfully kept a reef tank for seven years. My original fish are still alive and thriving. I owe it to following the advice I've learned on this
I apologize in advance for my lack of physics knowledge. I also apologize for the lengthy email as I don't know what information is important. A couple months ago I moved and had my reef tank upgraded to a 120 gallon tank at the same time. It is a room divider tank and visible on three sides. The overflow is located on one side of the tank. It currently has one 1" drain
<Mmm; too small... needs to be... "over-sized"... at least 1.5 inch for this volume system, sump... in fact, two drain lines would be preferable to one... Oh, I see below...>
with a Durso, one 1" drain that is unused,
<I would use this drain as well>

and a 3/4 inch return. The return is rated at 1200 GPH. There have been problems from the start. The Durso appears to be tuned correctly with no flushing. To start, the drain line vibrated/shook and sounded like a dishwasher.
<Yes; overwhelmed... siphoning intermittently.... maddening noise wise>

We attempted to solve it by cutting the drain line shorter to allow it to hang straight down and just below the water level in the filter sock. The noise and shaking continued.
<Ah yes>
We then drilled a few holes in the line to allow air to escape. This greatly reduced the shaking and noise, but did not eliminate it.
<Won't do so... either have to slow the rate of flow down (by pumping less), OR adding another drain (of size), OR re-drilling the present drain line, fitting a larger through-put/bulkhead fitting and larger diameter
I have an auto top off unit in the sump/refugium that beeps if the water level rises above the sensor. At least once a day the water level in the sump rises and sets off the alarm. Tonight when it happened, I watched the sump water level go back down to below normal. I then noticed that the water level was unusually high (by a couple inches) in the overflow. The water level was higher, but not "flushing." It also seemed like the drain line was substantially quieter. I turned the pump off to check for an obstruction in the drain line, but couldn't see anything. When I turned the pump back on, the level in the overflow was back to normal, but the level in the sump was too high again. It makes me nervous having the water
level fluctuate like that.
<Ah yes>
Do you have a guess as to what the problem is?
<Indeed I do... very common w/ undersized plumbing as you have here... the system is oscillating twixt flow and siphoning down the one drain line... when the water is backed up in the upper tank, the sump is drained sufficiently to set off the auto top off alarm...>
I'm assuming the problems have something to do with the drain not being able to handle the return rate. Is that correct?
<Ah yes>
If so, would it help to utilize the extra 1" drain?
<I would employ it and hope it does so>
If so, is it ok to have two dursos in the same overflow?
I already inquired about making the drain holes bigger, but was told the holes were as large as they could be with there being three holes in the same small area.
<Yes; an engineering/design defect. There have been quite a few commercial systems... and custom with this mistake>
Thank you in advance for any help you can give me.
<I would first try using both one inch drains... IF this doesn't "do it", I'd slow down the rate of flow to/from the tank... and provide more flow INSIDE the main/display tank with submersible pumps (see WWM re); using the sump less... IF this doesn't satisfy, the present holes can be abandoned, a piece of material placed over them and the tank/drain area re-drilled, WITH one larger drain line (2" if it were up to me) and a one inch return. Bob Fenner>

Plumbing/return question, and pump sel. for circ. f'      10/5/13
I have a 65 gallon tank with a 40 breeder sump in the basement.  I have a 1" return coming back up to the tank.  My return splits in the tank into 2 loclines.  I did this because I wanted to spread out the flow more and because I like to keep one of the nozzles near the surface for a siphon break. 
<A good plan>
When I initially finished the build I had the 1" splitting  into 2, 1/2" return locline nozzles.  But it looked so tiny, I switched it to 2, 3/4" returns before the tank was even running.
<A good move as well... even "induced drag" in such a small (1" ID) pipe is considerable over a good run (length), rise (head)>
Soooo does it matter what size these are?
<Oh yes>
 Is it better for my pump one way or the other?
<Yes to put it most simply. The discharge of the volute (cover over the impeller) should not be "downsized" in terms of fitting (MIP or FIP)... so, it should be 1" as is your plumbing at that point. The restriction further up, at the points where your loc-lines are transitioned, is fine to reduce to 3/4"... I should and hence will mention that most of your flow I'd provide "in tank"... not via a sump, esp. one in a basement>
 I've had the tank running several months with the 3/4 ", the only thing I noticed is that the flow out of the nozzles is just ok, even with an oversized pump.
<Mmm, yes; problematic... cost of electricity, likely increased waste heat... Do you understand what I mean re using in-tank pumps? Please read here: http://www.wetwebmedia.com/marsetupindex2.htm
scroll down to pumps, circulation...
Thanks so much!!
<Welcome. Bob Fenner>
Re: Plumbing/return question     10/5/13

Thank you Bob!
<Ah, welcome Kris>
  Yes, I do understand what you mean by in-tank pumps, I have 2 nice sized powerheads moving water in the tank as well and flow seems very good, fish and corals aren't overwhelmed and yet I haven't noticed any stagnant spots as of yet.
<Ah good>
 I appreciate your feedback on the return nozzles,  Since making the switch to the 3/4, I've wondered if that was the right thing to.
<Mmm, yes... as we can likely agree/concur: "Life (indeed the universe) is a "series of compromises"... Here, trading pressure for volume is the right trade off... IMO/E of course... but there are (of course) "means and extremes" of this situation... i.e., one doesn't want maximum pressure OR volume at the expense of the other>
 The "just okay" water movement is fine for the tank for filtration and sump movement, my concern was whether the 3/4 could be too big for some reason.
<Mmm, no; not>
The pump I'm running is the Sicce Syncra 12 hf, which everyone says "whoa that's overkill", however with the head pressure I have (sump is also over about 6 feet as well as in the basement) and the fact that I am running a UV sterilizer and reactors on it as well, it seems to be doing the job nicely.
I see this detail "Syncra 12 3200gph, 1-1/2" inlet, 1-1/2" outlet, 17.5' max head, 7.40psi".... I would definitely use 1.5" diameter pipe on the discharge here NOT the 1". You can keep the 3/4" discharges at the tank, but you're shortchanging yourself presently>
Thanks so much for all you do for this site!  It is a wonderful resource!
<Glad we are of service. BobF>
Re: Plumbing/return question, circ. pump    10/7/13

Hi Bob,
<Hello again Kris>
I do have 1-1/2 pipe coming off the pump itself, but it splits into 3 1" pipes.  One returns to the tank, one goes to the uv sterilizer, and one goes to the reactors(and also goes down to 3/8" line).  Uv and reactors have valves to adjust the flow.  I had the tank drilled for a 1" return, my original pump was a Speedwave dc 10000 with a 1" output.  The transformer
burned up after only a month of use
, so I am keeping the replacement as a spare as I really don't trust it.  The heat it produced was evident in the warped plastic and charred circuits inside, and I'm lucky my son was home
and was able to deal with it when it cooked. 
<Too much head, resistance... Likely your present pump has the same issue.
Did you read on WWM re circulation pumps and plumbing? B>
Thanks so much for your help!!!

Plumbing a 95 Gal FOWLR -- 05/04/09
I am planning the setup of a 95 gallon FOWLR tank (36"x24"x24").
<<Nice dimensions>>
I will order the tank with two vertical overflows, but I am not sure if I should go with 1.5" holes at 750gph or 2" holes at 1200gph.
<<It depends on your plans/plumbing'¦ The 1.5' will probably suffice, but having the extra capacity of the 2' available when/if need is always nice>>
Is 2" overkill?
<<No'¦ Especially when it comes to easing plumbing noise issues>>
Also, if I install a closed-loop manifold, does this change the answer?
<<Not really'¦ More detail on your plumbing plans (pumps, desired flow, etc.) would have helped here, but based on the size of the tank I'm guessing a 1.5' drain will provide ample feed to the pump you'll be using for the closed-loop. And the other 1.5' drain will process enough water (and likely more than you will want to deal with noise-wise) through the sump. But like I said, going with 2' drains will provide a bit more leeway in either direction'¦is up to you>>
Thanks, as usual.
<<Happy to share'¦ EricR>>

Re: Plumbing a 95 Gal FOWLR -- 05/05/09
Thanks Eric and crew.
<<Quite welcome>>
Now more details on plumbing plans for your review:
* Main Display: The 95 gal. glass tank will have two sets of overflows, each overflow drilled for a 2" drain to sump/fug and 1.5" return to tank.
* Sump & Refugium: I have a custom made acrylic sump/refugium that is 30 gallons total (really 20 gallons with water and 10 gallons in case of tank backflow).
<<Do test that this will be adequate'¦it is not unusual for the reverse (10g running capacity and 20g 'empty' volume to catch all the transient water volume)>>
The sump is split down the middle (long ways) with one side for the refugium and the other side with a skimmer section (AquaC Urchin with Mag Drive 3),
<<A good skimmer, but marginal in size for the system'¦in my opinion (I would have gone a size larger). This doesn't mean it won't work out fine'¦time will tell>>
baffle section and return area (using a Mag Drive 9.5). The refugium section overflows in to the return area.
<<Sounds good>>
* Goal: My goal is to incorporate a closed-loop manifold and accomplish a total turnover of about 1500 gph (15x), as well as capitalize on the redundancy of the overflows which can handle 1200 gph each. So now the big question: How to do it?
<<'¦? Here and among the associated links: http://www.wetwebmedia.com/cllooppbfaqs.htm >>
* Drains: After reading a ton of strings on WWM, it seems I should bring both 2" drains down to the sump and tee each of them off with a ball or gate valve to adjust flow to the refugium to about 10x.
<<Mmm, no'¦ If you are planning a closed-loop, you will need to plumb one of these drains directly to the pump used for the closed-loop. Remember, as the name implies, there is no 'open' portion of the loop such as the sump/refugium. Utilizing a 1500gph pump to pull water from the sump and return it to the tank via a manifold is simply just that'¦a 'return manifold''¦and in a 30g sump will present a whole host of problems re bubbles and noise, I assure you>>
That way the 'fuge gets a dose of raw water from the display, with the balance of the water going into the sump for skimming. What am I missing?
<<As just explained>>
Is there a better way to accomplish this?
<<Indeed...if you really want a true closed-loop. The refugium can be fed via a 'tee' off the one overflow that will be servicing the Mag 9.5 return pump>>
* Returns: I am honestly confused by all the info I have read about plumbing back to the display when you have dual overflows and what to include an over the top closed-loop manifold. I ended up my reading with the thought that I need two submersible pumps (maybe Eheim 1262s based on 5' head pressure) going from the return section of the sump - one used solely for the manifold system (which will have 3/4" PVC framing and five 1/2" outlets with loc-line)
<<Do consider that you need about 300-350 gph of flow after head-loss and 'per ½' nozzle' to achieve good flow>>
and the other to the 1.5" overflow return lines using a tee. This would make a total of three pumps in my sump, which may get crowded.
<<Yes'¦ Not to mention the noise such flow through a 30g sump would cause. And again, what you propose is not a true closed-loop'¦but a simple return manifold>>
I would then want to install dedicated GFCI outlets to power each pump. I have read about using an external pump like the Reeflo Snapper or Dart to power the returns, but I have never used external pumps and would have to drill the acrylic sump (which I would like to avoid unless it is the best way to go).
<<The external pump is the best way to go for the 'closed-loop''¦yes>>
I guess the plumbing with the external pump would be similar? What is best option to accomplish the turnover I am looking for?
<<I prefer Tunze Stream pumps (or similar) for flow within the tank'¦and I hear many folks like the Koralia pumps as a cheaper solution>>
As always, thanks for your time and sharing of knowledge.
<<Quite welcome'¦ Do consider my statements'¦and read up on the closed-loop to gain a better understanding re'¦and then write back and let's chat about all this further. Regards, Eric Russell>>

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