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More FAQs about Plumbing Marine Systems 9

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

Related FAQs: Marine Plumbing 1, Marine Plumbing 2, Marine Plumbing 3Marine Plumbing 4, Marine Plumbing 5, Marine Plumbing 6, Plumbing 7, Plumbing 8, Plumbing 10, Plumbing 11, Plumbing 12, Plumbing 13, Plumbing 14, Plumbing 15 Plumbing 16, Plumbing 17, Plumbing 18, Plumbing 19, Plumbing 20,   Plumbing 21, Plumbing 22, Circulation Plumbing, & FAQs on: Plans/Designs, Parts: Pipe, Valves, Back-Siphon/Check-Valves, Unions, Tools, Solvents, Use of Flexible Tubing, Leaks/Repairs, & Durso Standpipes, Overflow Boxes, Holes & Drilling, Bubble Trouble, Plumbing Noise, Make Up Water Systems, Pumps, Plumbing, Circulation, Sumps, RefugiumsMarine Circulation 2, Gear Selection for Circulation, Pump Problems Fish-Only Marine Set-ups, Fish-Only Marine Systems 2, FOWLR/Fish and Invertebrate Systems, Reef Systems, Coldwater Systems, Small Systems, Large SystemsWater Changes Surge Devices

"An Engineering View of Aquarium Systems Design: Pumps and Plumbing," by
Sanjay Joshi, Ph.D., Nathan Paden & Shane Graber. It can be found here:

- Gas Bubble Disease? Restocking after Tragedy - Howdy y'all! I recently lost a 5" Saddleback Butterfly, 3" Coral Beauty Angel, 4" Lyretail Anthias, and a 3" Firefish Goby. <I'm sorry to hear of your losses.> I moved about a month ago and went from a 55g that had been running for a year to a 125g. The move went rather well, and I managed to have the 125 running for a week prior and moved all the water from the 55g into the new tank along with LR and the inhabitants. All the critters were doing super UNTIL last week when  I started running a sump I created using an old 50g with acrylic dividers that created a sump and refugium area. From the start my tank was filled with micro-bubbles. I spent all that day attempting to correct the problem, and did to a certain degree I thought by the time the lights turned off. Low and behold the next day the bubbles were back with such a fury there was barely 6" of visibility in the tank. After another day of trying to correct the problem I succeeded, but I believe it was too late. Within 5 days I lost 4 fish with the Butterfly holding out the longest. All fish showed rapid gill movement, frayed fins and a slight bloating of their entire bodies. I am assuming this was GBD and not poisoning from something in the sump, as both my shrimp survived and molted a week later (it was due) and my Bar Goby also made it through and seems to be doing fine although a little shy lately. <For GBD you should also see actual bubbles that look as if stuck to the fish, these are actually gas bubbles under the skin.> I let all the PVC cure over 24 hours and rinsed it thoroughly...any ideas? <My guess is combined stress along with perhaps too much 'air' in the form of bubbles complicated things in the tank, in a way rarifying the water making it difficult to breath, but perhaps not the actual gas bubble disease.> While still in mourning I have begun to plan the restocking of the tank and would either a Passer Angel or Maculosus Angel as the centerpiece. I'm really at a loss for what other medium/small species I should be considering. <Many choices.> It's a 125g with Tunze skimmer, 75lbs of LR, 50g sump contains mechanical/chemical filtration and 25g fuge with 4" DSB and various algae. No wet/dry or other biological at this time. Was considering adding another 50lbs of LR or getting some type of wet/dry system within the next few months. What might you recommend? <Go for the live rock, skip the wet/dry.> Thank you very much for your time, you guys are such a tremendous help! E <Cheers, J -- >

Tap water purifier hookup Dear Crew: I am thinking to hook up a auto top up system using a tapwater purifier and a float switch... but I do not know how to hook it up... the tapwater purifier is a single unit, 1 chamber with ion exchange resin and carbon (from aquarium Pharm). it has a faucet water input (so it hook up on a faucet drain) .. and I would like to force the water to that purifier before it goes into my tank... I also have a float switch, the switch is connected to a plug, which is able to turn on anything. how do I mechanically hook this up?? <I would recommend that you fill a container (bucket, tank, etc) with filtered water, hook a small pump to the float switch and set the level you want. When the water drops below the desired level the pump will turn on and deliver enough water to raise the level back to the desired level. Make sure you do not allow a reverse siphon to be established as it may overflow the top off container> also, when the water is Deionized, do I need to add buffer to balance the pH??? if yes, which type? or if yes, do I suppose to store the DI water in a tank?? <Top off water (and change water) should be aerated for at least 24 hours before use. Then buffer the water to bring the alkalinity back to desired levels. Hope this helps, Don> Eric

Return plumbing Hola all, <Hola, ?Que Paso?> I have a plumbing question for which I have not seen an answer for in the FAQ's, I am hoping you can help me out with this.  I will have a 1" line coming from my sump return pump ( about 1100 GPH ) that will travel up the back of the tank to the top and then size down to a 3/4" pipe, then tee's, one that enters the tank through one 3/4" sea swirl in the back corner and the other that continues to the front corner and run through some of that black ball n socket type pipe into the tank. >Go 1" to 1" tee, then reduce to 3/4" to optimize flow to both. Then use an inline valve on both lines from there (3/4" pvc ball valves). Use slip valves (as opposed to threaded) to save space and optimize flow.> My question is, how do I set it up so that all the water doesn't come out of the sea swirl and just a trickle out of the other pipe(s).  I was told to use valves to control this, but I am not sure exactly where? <On each half of the line after the 1" Tee, use 1"X3/4" reducing bushing, 3/4" pvc ball valve on each leg.> This is for the right side of the tank.  The left side will have the same set up ( sea swirl in back and ball n socket pipe in front ) powered by a separate closed loop pump, also 1" reducing to 3/4".  I hope this makes sense???  You help is greatly appreciated. Thank you, Paul <Remember Paul, use larger pipe up to the point of the split to make full use of the line up to there. Don't run 1" line to a 3/4" tee, use a 1" tee, then down to 3/4" on each side of the tee. This should help. PVC valves can be purchased at Home Depot, Lowe's, your local hardware outlet.  Craig>

Closed loop system I am in the process of building a 1" PVC loop with ? tees that have 90 degree swivels(10 of these) that will mount on top of my 180 gallon reef tank. I plan on using a external pump some where in the 2000 gph range with a ball valve to control flow (any suggestions on type?). <Iwasaki's are popular> This pump will need to take the water directly from the main tank since my overflows are all ready maxed and the return from the sump is pumped back into main display. I would like to hide the intake that will be used to draw the water for the external pump (also protect my livestock from the intake). Would it be possible in your opinion to place the intake in one of the overflow boxes? <Ideal as long as the box itself can handle the flow.> Or would the water be pulled out faster than it would be replaced. <Depends on flow *now* and how big the box is, what it's designed for.> My other thought is to some how build a protective box around the intake and hide it with rock? Your thoughts and opinions are always helpful and are appreciated. <You could do that or perhaps split the intake between two overflow boxes? Complicates plumbing a bit, but might be better for box capacity. The other choice is larger overflows....not much help, huh?>  Thanks, Mike  Winston <Hope this is useful!  Craig>

Bubble Trouble OK. You've convinced me that it is an air leak.  How do I find it? I have some of that stuff that you spray on the outside of air lines and it bubbles up, but is that safe to use?  Any recommendations? <I'd use the bubbly stuff, myself. As long as you're not spraying it into the tank, you should be oakie. Good luck in finding the leak! Regards, Scott F.>

Setting up a 135-50g Tank  3/30/03 hey Phil,<Hey Tyler> I was wondering what I should do about overflows. the tank I'm getting is glass so I can't drill it and I heard siphon overflows suck so what should I do?<IMO, there not all that bad.  But I do catch a lot of heat for feeling this way.  As long as you make sure they are working fine you should be in business.> Also any tips on plumbing my tank, flow rate, recommended pumps for a 135-50 gal. thanks a lot, when I get everything setup I'll send you some pix.<Are you going to have corals?  A reef tank needs like 20x turnover per hour!  You have shown interest in a Huma Huma Trigger.  These little guys like to swim so you will need some current.  Yesterday I was at the Midwest Marine Conference and Eric Borneman did a wonderful presentation on "Water Flow".  There at a LOT of new ways to get everything moving around.> Tyler<Hope this helps!  Read up more here  www.wetwebmedia.com/pbfaqsmar.htm   Phil>

Water in drain Hi, I'm down to the plumbing details for my reef tank and I've got a question about a dead water spot. I have a portion of my refugium (bare bottom and live rock) intended for various purposes with the ability to drain it completely from a 3/4" bulkhead at the bottom.  This drain is plumbed into the house drain and the shutoff (or ball valve) is about 4 feet from the drain in the refugium. That means water will accumulate in that 4 feet or so of 3/4" inch pipe (the length from the bulkhead to the shutoff), until such time as I flush the drain.  Do you think that's a problem? Thanks. Lawrence M. Benjamin <Hmmm, not the best, but not likely a problem either. Is the bulkhead threaded? How about a plug in the bulkhead that you remove before opening the valve? Cheap, and it isolates that water if it bugs you. It will probably not be as "dead" as you think.  Craig>

Tiny Bubbles- Large Headache Hello to all <Hi there! Scott F. here!> I have finally gotten my 55 gal corner bow and 20 gal sump up and running. It was a long irritating struggle, but I think I have won. The Iwaki md30rxlt is in the basement and after a lot of experimenting the noise from the 2 - 1" overflows is down to a mere trickle.  You hardly notice the noise at all. <Sweet! That's a great accomplishment!> The last issue that I have been dealing with is bubbles. After I got it running there were tiny bubbles everywhere. You could hardly see through the water.  I changed the design of the sump slightly and now most of them are gone.  How many of these micro bubbles would it take to be harmful to my future inhabitants.  Do I need to do some more experimenting before ordering my live rock?  I can actually live with it the way it is now.  I just would like someone else's opinion on whether or not it is harmful to the fish.  The water is clear, but you can still see these micro bubbles all through the tank. <Well, excessive microbubbles in the water can potentially be a problem to sessile inverts and corals, by settling on them and interfering with their feeding and elimination processes. I would not be overly concerned about the potential for problems with the live rock, per se, but I'd look for the source of the bubbles to try to isolate them and eliminate that source. Often, microbubbles can be reduced or eliminated by re-checking all plumbing connections, creating a baffle to reduce the spread of the bubbles, and re-evaluating the circulation within the tank.> Thank you and good night Bryan Flanigan <Good luck, Bryan! Keep at it! Regards, Scott F>

Drilling for overflow Hello everyone! >>Hello, Dave! >I like the new prompts before asking a question...it should slow down the redundant questions. You guys have helped me a lot, and your forum is great too! >>Fantastic, good to hear. >I have a 30L AGA, and I wanted to drill it for an internal overflow. I was told to drill only the drain at a 1" bulkhead approx. 1" below the top frame of the tank. I was also advised to run the return( 1") over the back of the tank instead of drilling. What kind of prefilter could I then use? >>There are marine aquarium supply centers that sell a device that looks like a cone-shaped sieve. >What about a skimmer box to hide my prefilter? This seems to be more complicated than drilling through the bottom as I could use a 16" tall internal box that would cover the whole thing? >>Personally, I agree.  If you're going to go to the trouble, and *still* need a skimmer box, why not go with a Durso standpipe-type design?   >I plan on using an Aqua C Remora skimmer, and a sump underneath filled with live rock. >>Sounds like a good plan to me. >I also plan to have live rock inside the tank. I looked on the "wetdryfilter.com" site and it seems that drilling the bottom is standard...please help! >>You're avoiding the wet/dry in favor of a deep sand bed/refugium type of filtration methodology, yes?  Again, I would want to go with drilling a hole in the bottom rear corner of the tank and then utilizing a Durso standpipe design.  This would require the use of the skimmer overflow, but you were going to use that anyway.  This way, everything except the returns would be contained within this overflow area.  Look here--> http://www.rl180reef.com/pages/standpipe/standpipe_menu_nj.htm >>And here--> http://www.aurx.net/saltwater/durso.html (a Google search has turned up much in the way of designs and information.)  Also, besides the WetWeb site, good information can be found at http://www.reefs.org/library >I have great appreciation for your advice, and anything you could help with would be great. Thanks in advance.-- Dave Adams >>You're very welcome, please do let us know how everything works out.  Good luck!  Marina

Increasing flow rate Hi Guys!  Thanks for taking the time to answer my questions.  I've read thru tons of your articles and can't seem to nail down the answer (most likely due to all the variables in supplies for the aquarium.)  My setup was designed by a very reputable "local aquarium / pet shop" (Lot's of nice fish and reef stuff, not a bunch o' wannabees if you know what I mean) and I'm having some reservations as to the flow rate produced by this setup. Here's what I have...All-Glass 65gal FO tank, Two 1" holes drilled at the top for feeding the sump thru 1" Vinyl Tubing.  The sump is a 20gal tank below the display tank divided into 3 compartments, The 2 gravity fed overflow tubes enter a 100 micron bag in the first compartment and I also have an ASM G1 Protein Skimmer in the same compartment, next over is a stack of  2 bio blocks 12"x12"x1" separated by eggcrate, next over is a Activated charcoal bag on eggcrate and the return 1" bulkhead to feed the pump (Little Giant 2-MDQX-SC) via a 1" vinyl tube.  Note: sump was drilled on the side not the back so an additional 90deg elbow had to be used to facilitate plumbing. (Yes a tight squeeze. but it fits) From the pump output it is reduced from the 1" pvc to 3/4" pvc, then a 90deg elbow feeding 3/4" vinyl...up to the display tank, then "3" 90deg elbows to allow it to hang over the top edge of the tank (w/o falling out. so far) which then splits to 2 flex pvc ball type tubes and flared nozzles at the end. Note: all bulkhead exits (in the tank and the sump) have those black plastic basket looking things on them.  I would like to upgrade to an Iwaki WMD-40RXLT (eventually going reef in another tank and will utilize this pump) but I'm not sure I will be feeding the sump adequately.  What are my options for increased flow?  Is there a better choice in pump size?   <The overall limitation is the overflow capacity (you can't pump in more water than you can drain...well you *can*, but you won't like it! The restriction most affecting you right now is the plumbing you are using. The pump is clearly designed for 1" pipe *minimum*.  Reducing the outlet to 3/4", then to 3/4" vinyl which actually reduces the actual size to 1/2" to utilize barbed fittings, and you reduced a 1" output to 1/2". That's where your pressure and flow rate went. You need bigger plumbing, I would use 1" -1.5" PVC depending on head height, capacity, etc.> I'm really not happy with the Little Giant pump...very noisy, residual oil comes out occasionally (I try not to over oil) and collects dust, runs hot...etc... I'm truly sorry if this was long winded, but I wanted to paint the picture so you guys would have an exact layout to work with. <Determine the capacity of your overflows, then size the pump to provide slightly more accounting for head height, plumbing, etc. Use a valve to adjust output. Iwaki's are good, there are other reputable manufacturers.> One last quick one...On my protein skimmer, is there any type of tubing or something I can use to seal up the connection for the Sedra 3500 to the main skimmer body?  It seems that after a week or so it vibrates out a little bit and the air bubbles reduce forcing me to push it back in.  I'd like to say that the suction cups on the bottom of the pump suck....but they don't :)  Thanks for all your help in advance!  Keep up the good work!  Anthony Palladino <Hmm, I'm not familiar with your problem, perhaps contact the manufacturer.  Craig>

Plumbing parts I do not know where I would get answers if it were not for your website and crew!  This is not as much a question but here goes. I am trying to find plumbing supplies to make a circulation system for my 180gal reef tank (tired of the power heads not staying where there told) but I am having a hard time finding the correct parts. So far I have a external in-line pump rated at 740 gph at a 4 ft head (lifeguard quiet one pump) and some 1"pvc,elbows etc..  What I cannot find are the adjustable tee's to connect to the pipe. Any ideas on where these can be found. Thanks again for all the help and advice. Mike Winston <Hi Mike, try any of our WetWeb sponsors like Dr's Foster and Smith or Custom Aquatics, they have a good selection of plumbing supplies.  Craig.>

Noisy overflows Greetings to all I have been searching all over for information on quieting sumps down and would like to know if there is anything else I can try.  I have a 55 gal corner bow with a 20 gal sump.  I had 2- 1" bulkheads put in. On the inside of the tank there is a 1" service elbow pointing up with a coupling on top with slots in it. (that is my makeshift strainer)  On the outside of the tank I have a Tee attached with hose running down to the sump.  In the top of the Tee there is a short piece of pvc with a cap on top.  The Cap has two holes in it.  One is to vent the line and the other has a piece of 3/8" clear vinyl running down to the bottom end of the 1" line to vent the bottom.  The hoses are just under the surface of the sump water when it is running.  I tried having them above the water, but the noise and splashing were extremely loud.  I have an Iwaki md30rxlt pump returning water to the main tank. <Look at Durso pipe overflows to figure out how to vent these quietly. I don't think the 3/8 line helps. may hinder venting. Also, run water over splash plate w-filter pad in sump to quiet bubbles and splashing.> The two noises I am trying to deal with are the constant waterfall noise from the water running down the hoses and the hum coming from the pump. The waterfall noise has me pulling my hair out. The Iwaki is mounted to the bottom of the cabinet and has a piece of 3/16" rubber under it.  It is lagged down and I think that the cabinet is amplifying the hum. <Yep, bolting down to cabinet makes it part of cabinet....and it's larger vibrating hum.> Any ideas? <As per your new post, you moved it downstairs for noise and heat. 10 degrees increase in heat isn't good.....is the pump too big?> One more totally unrelated question.  We have put in a Deep sand bed and I am going to purchase a detritivore kit as well as 44 lbs of live rock to reseed the rock I already have.  Which should I add first?  The rock or the critters? Thanks Bryan and Dana Flanigan <I would add the rock first.  Hope this helps!  Craig>

Overflow capacity Hi guys, I really appreciate if you guys can help me. I just bought a 80 gallon bow front tank Clear for Life) with a built in center overflow. The bottom of the tank is drilled with a 1.75" hole which with the bulkhead makes it 1". The return on the top of the overflow is about 1.25" hole but with the bulkhead it makes it 1/2". I  just have the holes without the bulkheads in place right now. What is the maximum drain or gph that I can get with the 1" drain. Also, would  a Iwaki MD 20RLXT  be okay for my tank's overflow. I am worried that it may not be enough flow to cycle it around 480gph. Is it? Thanks a ton. Alex <Hi Alex, please check out the marine set-ups articles on WetWebMedia.com.  The 1" overflow should be fine for 480 gph, but you should factor in head height as this will effect the output/capacity of your pump. Plan to oversize pump to accommodate head height and plumbing, and use a valve downstream of pump to throttle back flow if needed. Make sure you test bulkheads and plumbing before full fill.....  Craig>

PVC glue Hi All, Quick plumbing question.  Is there a major difference using the 2 part primer and cement for gluing PVC plumbing, or can I just use "Christy's" PVC cement which is a purple one part cement that doesn't require the primer??  Also, maybe a silly question, but I imagine once it dries, this cement is non-toxic, correct?? There is no way to apply without getting some that will be exposed to water. Thanks. <No, no major difference. Make sure you clean pipe ends and fittings well. Yes, it actually welds the pipe together. Apply a  thin coat evenly to each part and twist when assembling, hold together for about a minute to prevent the reaction of the glue from forcing the joint apart. Wipe out as much excess glue as possible. Let cure 24 hours with plenty ventilation. Should be fine after that. Craig>

Closed loop flow rate I posted a similar question on the chat forum and the responses spawned a new question.  I wanted to know how much head pressure loss I have with my current closed loop wave-making system with a SQWD and the best advice anyone could give was that each 90-degree elbow adds about 1 foot of head pressure.  This information is consistent with the ReefCentral calculator, <It isn't. Just go to RC and enter the param.s.> but if this is accurate I should be getting no flow out of my SQWD at all.   <Yep, it assumes you are getting the right info from the chat....best to just go to RC. In your case, friction factor/pipe size, horizontal length, number of ells.> With 1 foot of head pressure, 5 elbows and 1 SQWD that's 7 feet of head pressure.  According to the manufacturers specs I should be getting no flow out of my CAP2200 at that amount of head (says N/A).  Do you know what these calculations are based on?  Are they "calculations" or are they anecdotal? <No, they are real, but you can't assume one part of a complex equation and make it a simple calculation.> Needless to say, I am getting flow out of the returns... not as much as directly out of the pump, but seems to be at least as much as a powerhead... may upgrade anyway though. Jeremy <Of course! Best to engineer a system to move the volume of water you need, than to just upgrade pump. Plumbing size may be a factor as well. Better to look at all the parts....  Craig>

Plumbing Flow Question Ok, I've contacted the makers of the SCWD and been informed that each produces approximately as much head as a 90deg elbow. Here's my question, since I can't seem to find any of my plumbing info: I was looking at putting a Mag9 on as my return, fed through 2 SCWD's to provide current (having a T on the outlet from the sump). It's 2.5 feet from the sump to the return, with 1 existing 90deg elbow. The Mag9 produces 900gph (how nice, a pump number that correlates with return rate, other manufacturers, take heed), so would this be too much for the overflow (a standard 1" drain) to handle? Thanks all! PF <Hey PF!  How are you? I would use CPR overflows with 1" PVC as the guide for passive flow rate. You can plug this data into the RC head calculator and figure your flow fairly close. If I were you I would go for it and install a valve downstream of the Mag so you can adjust the flow as needed. If you're like me, you want to optimize the flow rate! I suspect you will end up with about 700+ gph with plumbing, head height, ells, SCWD's etc.  Hope this helps!  Craig>

Metal Inside Check Valve Hi, I'm planning on using a check valve for my return line from the sump to the main tank. When I got the check valve home, I noticed that it has a piece of metal and a metal screw inside of it. Is this safe to use? Much thanks for a fantastic web-site! Greg < I wouldn't use this just to be safe.  There are check valves made for this application, check our sponsors for these.  Cody>

Re: Metal Inside Check Valve Hi Thanks for the great advice. One last question :) I woke up this morning to find a piece of hardened silicone sealant floating in my tank. I did some PVC work for my sump and used silicone sealant, but I let it cure for 24 hours before using it. Is this something I should be concerned with? Do you think my water in contaminated? Regards, Greg <I wouldn't worry about it. Cody>

- Plumbing Question - Hi all! <Good morning, JasonC here...> I have 2 3/4" returns and 2 1" drains.  Using a Dolphin 2100 pump straight up with 1.5 to a 1.5 Y with 3/4" reducers on the outputs.  From there 3/4" to hose barb and 3/4" flex hose to another 3/4" hose barb screwed into return bulkhead.  The drains are 1" slip.  What would be proffered to do the drains back to the sump?  a 1" 90 elbow with hose barb to 1" ID flex line or just a 1" coupler with hose clamped onto that? <Try to avoid the 90 degree elbows if you can.> Want the most flow back to the sump. <I think you'll be fine.> Thanks everybody for all your help!! <Cheers, J -- >

Re: overflow (good kind) and overflow (bad kind) with sump Hi folks! I've been reading here furiously on sumps, 'cos I want to add one to my 37g FOWLR, but I have two questions I can't find answers to. The tank has - for better or for worse - an Eclipse hood, and is not drilled. I need a hang-on overflow to get water out to the sump. Now, the primary reason for the Eclipse was that it is quiet - my wife doesn't like the living room sounding like a babbling brook. It also minimizes evaporation, which helps keep this small system stable. Is there a quiet, effective solution to feeding a sump, or am I SOL (highly technical term ;-> )? <Not the best option overall, but in your case show on of our sponsors for overflow boxes, either U-tube or CPR. These require a venturi powerhead to pull the air out of the overflow in the event of a power failure, etc.> I've already taken out the bio-wheel, so the hood is now relegated to providing mech/chem filtration and light. Am I going to have to pull it off altogether in order to put a hang-on overflow on the tank to feed the sump?  You may have to get out the Dremel tool and cut a space or ?> Secondly, what happens if a hang-on overflow loses its siphon and stops refilling the sump? How does one stop the return pump from pumping the contents of the sump over the living room carpet? Do I put a partition in the sump to create a fixed, low quantity return section? I think I'd rather lose the return pump than my head ;-> Thanks! <No problem, see above. You may find yourself moving out of your Eclipse and using the existing tank as a sump! Have fun!  Craig>

Refugiums, macroalgae and reef plumbing Hello, <cheers> Can you tell me the best set up for a  Ecosystem mud filtration unit, my tank will be a 125gl with twin overflows. I need to know what is a good pump, and how should I run the lines from the pump to a heater/chiller (aqua-Therm) and back to the return. I want to have at least 1000-1200 of gph for the sump and I need at least 600gph for the chiller so it will not freeze up, that is the manufactures  states. I was thinking that I could use a Mag drive pump rated for 1500 or 1800gph to do the job. <please view the illustration and following links to get an essential take on the matter: http://www.wetwebmedia.com/plumbingmarart.htm http://www.wetwebmedia.com/pbfaqsmar.htm http://www.wetwebmedia.com/circmarart.htm http://www.wetwebmedia.com/reeffilt.htm how do you rate the Kent marine Biosediment to the miracle mud( I hope you are liquored up to tell me about it)? <I find them both to be equally useless and overpriced and would advise a deep bed of fine oolitic/aragonite sand instead (6" or more) :) > I also need to know why you said sea grass is a better choice than Caulerpa and why don't ecosystem tell you why. <actually... seagrasses are not the only or best alternate for Caulerpa. But Caulerpa is frightfully noxious if neglected and has been shown scientifically to impede coral growth. They are not found naturally together on a reef. Other algae like Chaetomorpha and Gracilaria are more stable and less toxic if neglected> They don't have the patent on plants, right so why promote a species of plant when  there  are ones that are better for filtration, <because Caulerpa was one of the very few "plants" available in the hobby when Leng Sy first developed his mud system and they are the only common macro that can remain in stasis if lit 24/7> how  can I get some of this sea grass. <seek Chaetomorpha or Gracilaria instead from IPSF.com (AKA "Tang Heaven" or Hawaiian "Ogo")... or from inlandaquatics.com ("Spaghetti algae")> thank you, and I appreciate you site .   Mr. McCoy   <kind regards, Anthony>

How much rock and drilling tanks.. 3/10/2003 Hey Guys...hello from Bonnie Scotland <Hey!! And you got Scott V., the Scottish guy.  Not to get to far off track, but I really am and have only been able to visit there once so far.  I can't wait to go back!  I just need to know in advance this time how many beers I need to drink to see Nessie.  I guess I didn't have enough when I was there!> I am very new to this scene, and am getting excellent information from your site, IMHO it seems to be the most informative of all the sites I've trawled through, and I'm delighted to have found it. <We're glad you found it too> With regard to being new to the scene, I mean Marine, many years ago I had up to 3 tropical tanks on the go, two 4 foot, and one 2 foot hospital/breeding tank.  However, once I had seen my first clowns playing around their anemone in my LFS, well over 10 years ago, I always knew this day was going to come (yeah, I know, better late than never). <Well, welcome aboard then :)> My old ball and chain <You don't get in trouble for saying that?>  and I got a new house, and finally I found the right spot to situate my dream, so now here I am, I have just ordered a 6x2x2 all glass tank and it'll be arriving next week.  As for Bio filtering, originally I was going to go for a Plenum system, but you have no idea how hard it is to get the egg-crate stuff over here, and even when I did locate some, would only sell me 4 foot x 2 foot in packs of 10, they would not split it. So, I've decided just to go DSB with LR probably about 75lbs(would that be about right)?  <Hmmm, you're in Scotland.  Would those tank dimensions be in feet? If those are feet, then that's about a 180 US gallon tank, and you'll need more rock. I think you should have as much as the tank will hold and still look good to you, but plan on one pound per gallon to start, at the least.  A friend of mine, who I am helping, has a 55 gallon tank that already has 120 pounds of rock in it and there's still plenty of space!>  Now I know a very important factor is the water circulation, so I was thinking of letting the water from the main tank run out via gravity to a smaller 4 foot sump underneath, housing a refugium of plant life, then to the skimmer. (I'd recommend it go to the skimmer first, but sounds good otherwise> I'm assuming chemical filtration won't be necessary here (Y/N)<Yes, it may be. I have to admit I don't personally, because I'm too lazy to change it probably, but a bag of carbon is never a bad idea!  Even if you decide to forgo carbon on a regular basis, you still need an appropriate space for it as you never know when it, or something else, may be needed.>  and out via a heavy duty pump (not sure what type or size to go for here, REEF)), and then back up into the main tank <Here's a great link on circulation! http://www.wetwebmedia.com/circmarart.htm It's the one I always refer to every time I forget :) But, don't forget to take head height into account when you are selecting a pump.>  Now, this mostly seem reasonably okay up to this point, BUT, today I was reading that it was unwise to drill a number of holes (for outflow pipes, I was thinking 4 or 5 at 1") into glass, because it causes hairline cracks around the drilled areas, which apparently will eventually split and burst. (this was compared to the likes of a crack on a car windshield, which keeps getting bigger until it bursts).  So now this has really dampened my spirits about this method, because I really wanted to do it this way.  I know from just reading the posts in here that a lot of the guys use a pump to extract the water down to their sump<Very bad idea! What if either pump fails?>, but you all seem to agree as do I that just gravity alone is best. Any recommendations as to how I could solve this, maintaining the same kind of system I'm aiming for, or is the thing about drilling the glass just rubbish?? <Well, neither really.  If you drill glass there is always that risk.  That's why any glass shop that will drill a tank offers no guarantees.  However, it is rare.  Any other way of getting water from the tank to the sump is fraught with even more dangers.  An overflow can lose its siphon, and pumps can fail.  As for how many holes, what size, how to configure it, I would start by reading all you can here first:   http://www.wetwebmedia.com/plumbingmarart.htm, along with the associated FAQ's.) One more note of interest is that I have noticed that a number of people who post here, when setting up a new tank, during the cycling period talk about introducing a few Damsels to help the process. Well, I kind of understand why they would do this. Check this out!! I have a few books on setting up your first Marine Aquarium and inside, when they discuss the cycling period they actually STATE that introducing a few hardy fish (Damsels) would help this process along, as well as introducing some welcome activity in the tank! Honest they really do. Don't get me wrong, I would never dream of doing this, it's suicide if you ask me. I'm quite content to let the LR do its job for about 6 - 8 weeks before even thinking of introducing anything.  But it just shows you, if there's one, two or even three books that say this, there's probably others. <I know without a doubt that there are MANY books that will say this.  However, most of those same books probably don't even mention live rock, much less discuss it. As in many other areas, the technology and knowledge is constantly changing.  I can't keep up with myself.  It really wasn't all that long ago when live rock wasn't even an option.  The only decision was what kind of fish to risk first.  And yes, in that scenario, the damsel won hands down.  But, we have live rock now, deep sand beds or plenum systems, and protein skimmers.> Many regards, and thanks for your time <No problem.  It's too early for bed and too late to start a new book anyway!> Sorry it's more like a tome than a query question, I just like to think introductions come first.. P.S....my postman seems to be taking his time delivering Bobs book...I hope it comes soon  :-)  <Scotland has mail????  :)  Enjoy the book once you finally get it, and enjoy the tank.  Again, I really hope those dimensions you gave were in feet and not meters!  Have fun.  Scott V.> Cheers guys Raymie (Scotland)

Overflows Hi this is Dave again, with more questions. <Hey Dave, go for it!> I finally settled on the tank size and built it. It's a 30w x 30d x 20h with all sides clear for a full walk around view. <Wow, I like it!> The tank is done, but now comes the overflow. I would like to make a center overflow with a Durso Standpipe and water outputs inside of the overflow. What's the smallest size overflow box that you think that would handle the flow from a Sen 1200 @1200gal. Hr With 50" of head thru ?" tubing from the pump to the bottom of the tank thru a ?" bulkhead into a ?" Y splitting in to two ?" tubes. Feeding two more ?" Y's feeding  four bulkheads with loc-line water nozzles one each side of the overflow box. <Well, you will want to size your *plumbing* to easily handle 1200 gph plus or minus for head/plumbing. Your overflow box will need to be big enough to handle the drain plus Durso, the ells, etc.  plus all of the return plumbing and ells, etc. The size box that will hold all that and allow you to get to it on occasion will likely have enough surface area to drain 1200 gph from the surface. The top of the box will be around 1/2" from the top, accounting for the slots. I would like the water level in the tank to be about 1/2" from the top. Thanks for any help. <Water level is a function of the height and capacity of the overflow. I would oversize the drain pipe one size to be sure. Likely around 1 1/2" pipe. Shop our sponsors for CPR overflows and note their pipe sizes for an idea of what you need for 1200 gph. Enjoy the new tank!  Craig>

Tiny Bubbles- Big Headache Scott F or whoever may be working (not me today. snow day...yah.) <Lucky you! Ya gat Scott F. again today!> Well I got everything done last evening but as you said expect a glitch or two.  I am having a bubble issue in my tank now.  Lots of little bubbles.  My configuration now goes something like this.  Overflow drains in skimmer chamber, which overflows into refugium, which overflows into another chamber  | | | 3 pieces of plexi  with the 1st and 3rd being higher than the 2nd piece to help reduce bubbles before the return pump.  Well obviously that wasn't enough.  So this morning I took the old finishing block from the wet/dry and sliced off some pieces to place in the last chamber to reduce the bubbles.  And it has helped a lot.  Is there a better solution for that config to get rid of the finishing block seeing I am about out of space in that thing?  The blocks will be cleaned daily with the skimmer since they are easy to get to and in the same general area. <To be quite honest, I would have recommended the same thing that you did...Just keep messing with it until you get the desired results...> Also my tank is hazy today.  Looks like a smoggy day in CA.    Just part of disrupting the tank a little yesterday?  Will this clear up?  Readings are all normal. 0's for what I test.    <Yep... you'll see some residual cloudiness for a couple of days until some of silt or other suspended matter settles out...Normal> Also added a 60 watt plant bulb above my refugium (are these ok?) <Should work...You may want to experiment with other bulbs if you don't get the desired results...> I cut a hole in the white plastic top and used a work light fixture to provide lighting to the refugium which now contains a 6" DSB, about 3 lbs of live rock, just some extra from other tanks (will add more when I come across it) and a few strands of Caulerpa.  Will that bulb be enough for the leaf Caulerpa to grow?   <Probably...this is a remarkably tenacious and adaptable macroalgae> And is that a good thing for the refugium?   <Personally, I don't like Caulerpa...to invasive, to prone to "crashing", and there are some chemicals given off by the algae that have been (arguably) shown to impact coral growth negatively...I like other, less "nasty" macroalgae, like Chaetomorpha and Gracilaria..> I have a very hard time finding algae strands or starter samples of things around here.  Have 3 LFS in the "area" (about 30 minutes away).  Nothing other than mail-order besides that.  The downfall of living in a corn field.  Any advice on getting or finding this type of stuff? <I love Indo Pacific Sea Farms....They offer a variety of macroalgae, as does Inland Aquatics...check them both out on the Web> I would really a good algae or plant start for down there.  I really need to get to this one LFS (about 1 hour away). Their reef tank sump has a severe overgrowth and would think they would sell me some or just give me some. <If you're willing to make that drive- they should do better!> One note on Mr. Fenner's book.  I currently do not have this and have looked in the library but they are a hillbilly library and carry no such books.  (I am a teacher) and had our school librarian check other libraries for it...no luck.  So she said she would order it for our library.  Not that my 11 year old students will have much use for it, but I will have it checked out quite a bit I'm sure. <Well- you might just start some kids on a positive life-long addiction! A great addition to the library, IMO!> Will keep you updated on the tanks progress and with more questions I am sure.  This site was an excellent find.  Thanks again. Matt <Glad to hear of your progress, Matt...Feel free to shoot us an email any time. We're really happy that you enjoy the site! Good luck! Scott F>

- PF Discovers the Durso - <Hi, Mike, JasonC here...> Until I read today's FAQ, I had never heard of one of these. I'm taking off from work early to go buy the supplies and experience this thing called "quiet" for myself. <Geese... you been living under a rock? ;-) Anyway, you'll find this design works quite well.> Thanks again guys! PF <Cheers, J -- >

Durso standpipe Hello, <Hi John, Don from NE with you tonight> I have 55 gallon fish/reef and am adding a 10 gallon refugium underneath. I have a bottom drilled tank which used to have a overflow stand pipe to the sump But very noisy!  I would like to use this to feed the refugium.  I search the Internet and located the Durso standpipe. It's an overflow pipe with a tee on top, continuing to a cap with a air valve mounted in. Out of the tee is a st. elbow into the water.  You can mount a strainer to the elbow.  They state that at power failure there would be no siphon to the tank below and no noise.  Have you herd of this method or is there another safe way to complete this. <Yes, many, many happy people using this design. Follow the directions for construction and you should be happy as well> Many Thanks, John from NY

Overflow volume and noise Hello, Getting ready to drill a 120 gal. tank and have a concern about the noise from the overflows.  I am hoping to turn over the volume of the tank at 20-22 times per hour. I have read that a 1.5" overflow (PVC) can drain water from the display tank  into the sump at a rate of 600 GPH (I  plan to "T" the 1.5" PVC on the outside of the bulkhead so air can escape as the water runs through the overflow into the sump). <Easily 600gph. Go to one of our sponsors like Foster and Smith, Quality, etc, and look at the flow rate of add-on overflow boxes with 1.5" pipe. If you are concerned with noise, under-using the overflow/plumbing size and using Durso style vents (like you intend) is a good plan. The water actually doesn't make any noise....it's the AIR being *sucked* into the drain that makes the noise. If it flows rather gently with enough room for a reasonable amount of air while draining it will be quieter.> I think I read somewhere that the 1.5" overflow can move 600 GPH,  BUT will create a lot of noise as it moves that amount of water.   <Probably not. A 1" pipe is rated for 600gph, so 1.5 is considerably more. Still, you will do well to use oversized overflows for noise reasons.> The suggestion was to plan for the 1.5 overflow to move only 300 GPH (1/2 it's capacity) and it will move the water much more quietly. <Please do check out the rating of the overflow boxes with 1.5 " pipe.> Is this true? <The theory is true, the sizes/flow rate need to be changed to protect the innocent.> If so I will refigure my plumbing and drill extra hole(s) and only expect the overflows to carry 300 GPH- but quietly. I continue to use your wonderful site daily! Thanks <Bigger is better, but 300 gph through a 1.5" pipe is probably a little overkill. They will do 600 gph without much problem. Check out the overflow plumbing, it will help!  Craig>

Re: Flow Rate Thanks in advance for the help! What rate of flow could I expect from a 2" pipe stemming from an overflow with two 45 degree turns? I have six such pipes on my tank and I want to match up the two return pumps correctly. Thanks. signed--- "Waiting to Buy Iwakis" <2" pipe can drain approx. 2000gph passively, but do be conservative in your estimates. I have two vats with 2" overflows, one drains 1800 gph easily, and the other drains 2000-2400 gph, but with an elevated water level as it is almost at capacity. Hope this helps!  Craig>

Re: new tank/overflow Hello, I'm having a new tank custom built for me.  I am thinking of a 50"x28"x28" (170gal).  I am trying to design the overflow and need some help. <Okay, I'll share your dream. This way I can live vicariously through your checkbook!> First, I plan on using an Ampmaster3000 (3000gph @ 4') return pump and plumb with 1.5" PVC to two or more outlets.  This is secondary water flow, primary will be with Reeftec wavemakers and possibly Tunze Streams later.  The questions is what diameter hole is required to accommodate the flow of this pump?  Would a 2" bulkhead with a Durso or Stockman standpipe suffice?  I would prefer not to scale back the pump, but will of course plumb it so it can be. <I would use two. IE: I have two large vats in my basement, one turns just about 2000 gph through a 2" overflow, but it is just keeping up and the 2400 gph pump is throttled back just a hair to accommodate. For a nice comfortable 3000 gph I would use two. You can also shop after-market overflow boxes and use the size of their plumbing/overflow ratings to get a good idea of the passive capacity of various size overflows. I'm conservative and use one size larger pipe. This way I can upgrade, fiddle around later without a complete rebuild.> Second, I am considering a center overflow.  Are there any considerations against a center overflow that I should be aware of? <Not really.> Third, in trying to design the center overflow I have some options which affect the surface area of the overflow.  I won't bore you with the details but I wanted to verify something.  In Anthony Calfo's book he states that you want the "thinnest" amount of water to enter the overflow.  From what I understand the bigger the surface area of the overflow the "thinner" the water becomes making it more efficient.  Does this make sense? <Absolutely. See his full length overflow as an example. Larger box = thinner film skimmed, another good reason for oversized overflow plumbing!> Fourth, I believe I will have one large drain in the center of the tank which will hit a 45degree elbow and flow down the far right side of the cabinet and enter the sump.  That compartment will also hold the skimmer. I've seen some designs where that chamber is filled very high with water before going to the other 2/3rds of the sump where the water is about 1/3 the height of the sump.  Is this a way of reducing bubbles? <More likely a skimmer box with holes/overflows set at the desired optimum skimmer water level height. This *sets* the skimmer water level making it the same consistent level all the time, thus decreasing skimmer adjustments/fluctuations and increasing skimmer efficiency.> Is there any way to calculate, based on that much flow and knowing the dimensions of the sump, how to place the bubble baffles?  I am worried that if placed incorrectly that the velocity will be too high and the bubbles will be carried through the baffles.  This also makes me wonder about having a large area with no baffles before the intakes.  Any help here is appreciated as I am having my sump custom made so I have a lot of freedom... to mess up!  :D <No worries!  You likely won't need any baffles in the body of the sump. It won't hurt to use one baffle at the pump intake end that draws it's water from the bottom of the sump, but it is unlikely bubbles will make it the full length of the sump. They are unusually dispersed before exiting a well designed skimmer. Luckily baffles can be added at about any time.> I have many more questions but figure this is enough for now. Cheers, Chris <Have fun Chris!  Craig>

Re: overflow question Hi crew, I just redid my top to accommodate 2 175w MHs and had to modify the position of my siphon overflow boxes (I know, I know, but by the time I'd learned about drilling, it was far too late).  The overflow used to hang directly on the back of the aquarium.  With the new trim, molding, etc. I had to disassemble the overflow & screw it directly into the wood trim.  While doing so, I had the bright idea (?) to lower the inside overflow box so that the water level would be a bit lower in the tank.  The water level did go down...However, now the water level in the inside box is only about 3/4" below the height of the aquarium water (it used to be about 3-4" below). The outside overflow water level is about 1.5" below the inside overflow box water level.  I hope all this makes sense. <Absolutely!> From an observational standpoint, the overflow does not seem to flow quite as quickly as it used to.  Also, the inside overflow level doesn't change substantially whether the sump is full or near empty.  What makes it operate differently now? (I know my change in its position causes this, but why?) <When you lower the box and the water level, you make the siphon work harder to pull the water up over the lip of the aquarium, which is now higher in relation to the box and water level. See? The lower your tank water level gets, the less efficiently a siphon works.....that darned gravity again.> Also, is there anything I can do to improve/fix this apart from raising up the inside box again? Thanks in advance, John <Not unless they have a bigger tube to pull more volume against the added height. You will need to raise the water level again to return to the flow you had.  I hope this explains it for you!  Craig>

Water flow and overflows Hello and thanks in advance for any advice you might offer. I am recycling an old 75 gal. aquarium into a tank meant to house some live rock, soft corals and a light fish load. <Sounds Good> I have purchased a remora skimmer, built a hood housing 4 55w PC florescent bulbs and what I think is everything else I will need ( i.e. heaters, test kits, salt, supplements). I have an old 20 gallon aquarium I have also recycled as the sump for the 75 gallon. I have purchased a Mag 12 pump for use as a submersible for my return and am constructing the return so that the run from the pump to the "tee" on the tank is 1.5", 1" around the loop at the top of the tank and ending with 3/4" spouts at six points around the tank (btw...is standard PVC glue ok for this application?). <Yes you should use the pvc cleaner, primer and glue on all connections. Unless you are using thin wall pvc then you should omit the primer as per instructions> The head from the pump to the top of the tank is 4' plus whatever the tee and 3 90 degree elbows and the spouts add to back pressure. I am doing this to eliminate the need for power heads (I hope). <An excellent idea> My first question is will a Mag 12 provide enough circulation for what I plan to keep? Second, will I need power heads? And third, I will be using a CPR overflow since my tank is not drilled ( I don't really want to go there), how much capacity does the overflow need to have to accommodate the needs of the return pump? <The Mag 12 is rated at 1130GPH @ 4' head. But, alas, each elbow is +1' and each tee is +1.5' and each 6' horizontal run is 1'. With this new info, you head pressure is something like 9-10' and the Mag 12 is around 600GPH. You add the flow from the skimmer pump and you are probably around 800-900GPH, am I close? This would give you around 10x turnover which would be sufficient for low flow species. You may need to add some 'spot' flow to certain dead areas so maybe you could hide small powerheads in/around the rock. The manufacturer of the overflow will have a GPH rating and you should match the above. I would over design by as much as 20-30% to give yourself some elbow room on the overflow.> I hope this all makes sense. <And I hope you can make sense of the reply. Take care, Don> Thanks again.

Pumps-Let it flow!!! Hi, Craig Just let me clarify here to make sure I understand. The return on my pump is 3/4''.  As it comes out of the pump, I enlarge to a 1'' run all the way up to and through the bulk head which is >3/4''using an adapter, then 1'' again up through the over flows to the top of the tank, into the water! Newbie, Newbie, Newbie!!!!    Thanks Craig for your patience. Charlie Newbie <I'm glad you wrote back Charles!  Does your return from the pump run through a bulkhead at the tank? If it has to go through another 3/4" bulkhead, then run 3/4 " all the way as you won't overcome the 3/4" restriction, no matter what! You are only going to deliver whatever the smallest restriction in the system can deliver. Do you understand? If you had multiple 3/4" return outlets, you could up the pipe size and gain or preserve more capacity, but with one 3/4" return and bulkhead, the larger pipe won't accomplish much because it reduces to one 3/4" line. If this isn't clear, please write back!!!  Yours, Craig>

Drill or overflow? Hi all, I have a 90 gallon glass tank that I need to set up for a wet/dry filter w/sump.  There is a LFS that will drill it for me for $50.  This expense, plus the cost of bulkheads etc. will about equal what I would pay for a good hang-on overflow setup.  Which option do you think would be preferable? <drill it>  Any particular weaknesses of either way?   Appreciate any direction you could provide. Thanks, Jim <Hey Jim, I'd go with the drilled overflow, the hang on type will fail sooner or later and leave you with soggy floors. -Gage>

Plumbing?  Hi, Guys I was reading that if you are pumping your return water more than two or three feet of head that you should go to the next size bigger pipe to help cut down on friction on the return. Is this a good idea or not? Thanks   Charlie <This is the one area where bigger is better Charlie! Try using the calculator on Reef Central, it may help you.  Craig>

Rebuilding... Post Disaster/Plumbing Well, I've decided to take this set-back as a time to make some long overdue improvements. So...here is a flurry of rebuilding questions. 1) Upon moving all of the live rock (temporarily) to the sump, (I've been wanting to re-stack for a while, but there were always too many animals) I did a huge water change and gravel (Cr. coral) Vacuuming. I was HORRIFIED at the amount of putrid silty debris I sucked out of there, especially in the regions long since covered by live rock, which leads me to the question, Do I really need 2-3" of substrate, if it becomes a trap for all of this filth? Is it really serving any purpose beyond a foundation to pile rock on safely & distribute weight? <Nope, you really do not need it, you want to shoot for less than 1in, unless you are using sand and want to utilize a DSB.> 2) My tank is not drilled, so my set-up isn't optimum, but I am dissatisfied with my current method taking the water to the sump. Method is as follows...Overflow box in tank, J-tube to skim box outside of tank, 2" hose to wet-dry drip plate, wet-dry, siphon out to 50gal sump containing a Turbo-Flotor T-1000 Skimmer, Rio (4000?) 1000gph returning water to tank. Big problems when power goes out, as return pump stops, but siphon continues to pull out an additional 20 or so gallons of water until tank level drops below tube. This can get messy depending on how much water is already in the sump. <yup, J tubes suck, found a big bubble at the top of mine this morning, have not modified it to pull bubbles out yet.> I would like to come up with a central sump that this and other tanks could all share, but I cannot figure out the plumbing scheme in my head, pumping water out of the tank instead of a gravity siphon seems the way, but I cannot get my head around how to match the flow in to the flow out, where my siphon method regulates itself. How can I do this without drilling the tank? <Unless you are pumping it to something above the tank (refugium) and overflowing back into the main tank, pumping water out is not safe.  No sure fire way to match flow rates, also problems with power outages; one pump starts, one pump fails, one tank floods and the other runs dry.  Not safe.  Drilled tanks are really the way to go.> I'll stop now, as I am sure you all have a full plate already. <No problem, if you have not already, check out our plumbing FAQs, lots of info there.  Regards, Gage> Thanks, -Pat  

Micro Bubbles I need your guidance once again. <Okay.> I have a simple 40G glass aquarium serving as my sump, containing my BioWheel, UV sterilizer, and protein skimmer. The chiller and mechanical filter are on a separate closed system. My current problem is the micro bubbles that are in my display tank and I believe that they are from my protein skimmer (bubbles from it are being sucked into tank). <Your skimmer should be near the inlet to the sump from the overflow, the return pump at the farthest end from the skimmer, thus avoiding any bubbles as they disperse to the surface over the length of your sump. If not, add baffles, a skimmer box (a simple five gallon square bucket, cut-up will work nicely) or a pump box with baffle or sponge to stop bubbles, but this should be overkill. Is your return pump external? If so you should check all plumbing connections as well, it is more likely than skimmer bubbles.> The skimmer deposits onto filter media to help disperse these bubbles, and has been working fine until recently. I know these micro bubbles can be harmful to the fish. <Perform complete water tests, this could cause persistent bubbles.> My question: if I move the mechanical filter from the closed system to the sump system, after the pump (i.e. water flow: overflow/BioWheel/sump/pump/(filter)/tank, will this help trap / eliminate / stop the micro bubbles from reaching my main tank? I doubt it, More likely to gather in cartridge and blow out in bigger blasts than they are now.> I don't have the funds to change the sump itself (not to mention the time/effort to take down my display to do so). Always appreciating the help! Craig <Shouldn't take much if anything to separate skimmer and return enough to allow bubbles to rise to surface. Space, sponges, baffles, boxes all will work and are inexpensive to free.  I still would check water first.  Craig>

And now....plumbing, Calcium reactor <Sorry Kent, I saved your post as a draft until I could answer your calcium reactor question and it got posted before I could finish! I'll continue..> Looking for plumbing recommendations. (Clarity 135 with sump and calcium reactor). So far I only intended to use 1 Dolphin 2100 pump at about 4" head.  The skimmers are in sump with their own pumps.  The Dolphin get it's direct input from the sump.  Am I supposed to drill another hole in the sump and add a bulkhead to supply another pump for the Knop S-IV and put the drip back into the sump? If so, the input vs. output of the reactor won't be equal will they?  If they are then question answered. <Feed the reactor with a tee off the pump or use the drip line it comes with. The output is very low, so the input will be low as well. For maintenance, set it up in a convenient spot and plumb with tubing.> Also, I am thinking I have to T the output of the 2100 to go to each return, and likewise T the drains into the sump. <Yes, use valves to adjust flow to each. I don't know if you have to T the drain/overflows, they could have individual lines to sump if it's designed for them.> This seems like an equal in equal out deal with the exception of the bulkhead out of the sump the calc reactor. <Yep, the tank will only drain what is pumped up into it, with overflows properly set-up. The calc reactor will hold the majority of it's volume, so that water is not going to drain into sump and is not a factor in water level. There is no need for a bulkhead, this is a simple tubing set-up.> Can water height in the tank be used to adjust for drain rate versus return rate to compensate for any inequalities in sump levels due to skimmers and or the reactor? <How this works is, main tank water level is constant. Sump level varies a bit normally. The way you set this level is to fill the tank with everything off until it overflows into sump and fills to highest desired level. Now turn it on and it will be operating at the highest water level it should.  When and if power goes out, it will drain down to the fill level, provided you have siphon breaks in your returns. The tank drains from the surface, so it can only drain what you pump into it. Thanks loads, I wanna do this right from the start and have the least amount of probs. <No problemo!  I hope this answers your questions...if not, let us know!  Craig>

Drilling size Thanks for another quick reply....I just got off the phone with the salesman....he told me the largest return openings he could drill for was 1"....then he mentioned that neither he nor 3 other wholesalers carried 1" lock lines.  He advised me that 3/4" lock line is what everyone uses and that he couldn't even find 1".  He then advised that the way the system comes drilled standard is 3/4" returns and 1" drains so draining won't be a problem. <Just have enough drains to drain more than the pump capacity and enough returns to use the full capacity of the pump. Remember, the return is pressurized, the drains are *passive*. It's really just a matter of quantity now, not size.> He also advised that 2100 GPH was a ton of flow....said 15.5 turnover was way plenty and that if I wanted more current I should be using PowerSweeps on either side to get the current rather than using the recirculation pump to get it. <I wouldn't waste a single cent on PowerSweeps, they are complete trash and will last no longer than three weeks max. The required flow is 10-20 times, so 15 X isn't a big deal. Your LFS needs to update info!  Regardless, 2100 GPH is sufficient for most corals, perhaps not for others, like SPS.> AND he also mentioned that I may have wasted 800 bucks on a chiller... With a 14" high canopy and 3x250 MH I could have used a fan to keep the temps down.  He advised that even if the temps got up to 82-84 degrees I still wouldn't have to use a chiller, I could just keep the temps around 82-84 all the time.  I don't know...maybe I need to look into sending back the chiller and get more live rock!! <Well, depending on where you live and your summer temps, he may be right! You can use fan(s) inlet (pushing) and outlet (pulling) to keep the hood/air cool. I would still shoot for enough fans to keep it as close to 80F as possible. Up to 84 for short-term is alright. I would return it myself unless you live in FL or CA. without air conditioning.  Craig>

Re: Drilling size Hey guys, me again I ordered a Clarity Plus acrylic 135 Long tank, I believe the mfg puts the center positioned box in the tank, but as I understood the salesman, the drain and return holes are drilled by the salesman not the mfg. <This is good, it will give you some time to plan your circulation.> Either way the tank hasn't been made yet, what diameter holes for drains and supply should I have them drill for? <You will need anywhere from 1350 to 2700 gph for a reef, depending on your chosen inhabitants and their needs. I advise planning to accommodate the upper end which gives you the ability to update/size your equipment. It's not difficult to get more water pumped into the tank, the limitation is drilled drains, so plan those to take 2700 gph and you should be safe. Go to one of the WWM sponsors that sell add-on overflows, match your desired flow rate to the closest box9s) at or over 2700 gph and see what size plumbing they use to drain them. Perhaps oversize one size.> I ordered the tank originally with 2 drains and 2 returns.  At the moment I have only the Ampmaster 2100 pump which should have a straight shot up to the outlet at no more than 5ft head.  At that rate I should be getting 2100 GPH according to Dolphin, that's assuming I'm using 1.5 inch piping. <Slightly less due to plumbing loss, but close.> Should I have them drill all holes to 1.5" , 2 returns and 2 supply using that pump or in the future if I wanted to add another pump I would just add another 1.5" pipe for return?  My first intention was to Y from the pump from 1.5" to 2 1" but if you suggest 1.5" holes then I'll just Y from 1.5 to 2 1.5......I guess I need to let them know ASAP. And should that 2100 flow be enough for a 135 reef at a listed 2100 GPH? Thanks again and again <All you really need to hassle is the drain/overflow size(s).  You are wide open on return designs with no holes drilled! Your Dolphin at 2100 gph at 5' is likely fine for now. If you really want more you could add a closed loop with a pump in the overflow box, a manifold, etc. Take your time on the returns and think about what you want to keep. Think about your rock work, circulation, dead spots, etc. 2100 gph seems like a lot of water, until it gets divided up into all the necessary places! That additional 600 gph or so can come in handy if you are inclined to additional. redundant pumps. Redundancy can be good when a pump goes out, but it is rare...and added expense.  Again...2700 gph is the upper end, plan to drain 2700 gph and how you get it there is much easier to plan and plumb anytime. Splitting the existing 2100 gph return with one pump will work and then your drains will easily handle it.  You really need more than two return outlets.  Please see WetWebMedia.com google search on "marine set-ups", refugiums, sumps, plumbing, for much more info and ideas on circulation.  Hope this gets you there!  Craig>    

Re: one more sump/overflow/siphon question Hi Bob, I have been reading everything I can find on your site regarding sumps, overflows, and siphons. I have a 60 acrylic reef tank and I desperately need to get a sump going. I want to lower the water level just enough to drill holes in the tank  (without causing the reef inhabitants too much stress) because the siphon thing really scares me. My question is, can I make an overflow box and attach it to the inside of the aquarium? The box would be approximately the size of the boxes that hang over the side, maybe a little taller say 10 inches, and then attach a bulk head through the hole in the tank side and if my box is tall enough possibly even have a small stand pipe within the overflow box? <What would the standpipe do in the inside of the tank? The rest of this possibility sounds do-able> I have not seen or heard of this being done so I'm guessing it wont work. I like the idea of the overflow box that is as tall as the tank but can't come up with a way to install that with the aquarium full of water and animals. <A box acting like a strainer (overflowing through a bulkhead fitting inserted in the tanks side) will work... hard to devise a "standpipe" (to draw water from/near the bottom?) in such an arrangement. I would keep dreaming, scheming (have you looked at Ozreef.com?) here, chatting with other hobbyists, visiting tanks for now. Bob Fenner> Lynne Casal

And now....plumbing I have ordered a Clarity Plus 135 L tank, with dual returns and dual drains located in the rear center of the tank. To me this means I will be returning water to the tank from two outlets, each pointing 45 degrees off center and hitting the front. I am still questioning whether I should invest in some sort of attempt to alternate the currents or not or to add additional pumps or powerheads to perform this task. Also, Looking for plumbing recommendations. <Wow! Sounds nice! Since the two returns are already drilled, I would use them as intended. With a sump these may be a problem without a way to break the siphon in a power outage. If this is the case consider using these returns in a closed loop so it won't siphon into sump. If they are above the intended high water line then they can be used as standard returns from the sump (with a small hole drilled for siphon break or a big sump). As far as aiming, this depends on needed circulation, inhabitants, etc. Assuming this is for a reef, shoot for 10X - 20X times tank volume turnover total through all returns/circulation systems.> So far I only intended to use 1 Dolphin 2100 pump at about 4" head. The skimmers are in sump with their own pumps. The Dolphin gets it's direct input from the sump. Am I supposed to drill another hole in the sump and add a bulkhead to supply another pump for the Knop S-IV and put the drip back into the sump? If so, the input vs. output of the reactor won't be equal will they? If they are then question answered.

Sand and Tank Setup Question 2/19/03 Hello Anthony, <cheers, mate> Once again another question.....  I just received two Iwaki MD40RXT pumps ( box says rated 1344 gph ) for my 90 gallon.   <wow.. lot of flow. Cool> One for my sump return, the other for closed loop circulation, so I should be good to go on flow.   <easily at/outside the 10X-20X tank volume rating. Be sure your bulkheads can handle the return pump> With 4 1.5" overflows drilled in back, 300 gph per overflow/bulkhead should be easy to achieve and fairly quiet from what I have been reading.   <agreed> I noticed that some of the response in the FAQ's mention over sizing the return pipe size.  The outlet for the 2 Iwaki's is 1".  Should I go with 1.5" instead, <I would not bother... 1" is very fine> up to the top of the tank then shrinking down to 1" or 3/4" connecting to my Sea Swirls ( once I buy them)?  Or do I just go with the 1" from outlet to tank.   <I see no trouble with 1" all the way> There are no manuals in the box, and the www.iwakiwalchem.com site shows a manual but does not mention anything about pipe size. <if you are really interested in the dynamics of engineering with aquaria... seek Escobal's "Aquatic Systems Engineering". Lots of numbers in there> What about the small amount of pipe from sump to pump inlet, should that be 1" or upsized to 1.5" as well?  And for the circulation pump, I was considering 2 1.5" bulkheads/pipes in back of tank instead of just one, don't want that much suction from one hole, could be potential problem.   <agreed> But once again, do I upsize on the inlet and outlet, or stick with the 1"?   <not that much difference with 1.5 on the intakes... both will need guarded> I had asked about the pipe sizes before on a previous email, but I had asked the question, then made a statement about it and I was not sure if the response was answering the question, or agreeing with my statement, so forgive me for asking again, I just want to make sure I am clear.  I have spent the last month building a new stand that is big enough to be able to house the 30 gallon sump with the AquaC skimmer in it. <excellent> It had to have enough room to be able to pull the skimmer out for cleaning, etc.  Found out the first time around that it would not fit, curses!!!!   <bummer :) > So I had to rip bottom of the stand off and come up with a new plan.  Then there was staining the stand and making it look nice, buying all the plumbing, pumps, etc., so I want to make sure I don't get it all together then think "oh crap, I missed something". I know you have heard it a bunch of times from everyone, but you guys are life savers.   <its always redeeming/good to hear!> It is great to be able to have a source of GOOD information, not some salesperson at a fish store trying to make a buck! <most LFS are very good folks to be sure. But is nice to have independent consensus/verification> Every time I am at the LFS, I hear people asking questions and cringe at the answers they are receiving.   <alas... it does occur. And we have to fault the ownership here... what good businessman hires inexperienced employees for $5-7 per hour and expects them to be able to sell aquarium systems costing thousands of dollars? That's insane. At least without training. Better shops actually have ongoing employee training programs> I am no expert, but I have come a long way, at least enough to know that the answers the salespeople are giving them are pretty crappy.  I thank you, and all the livestock out there thanks you! <best regards, Anthony>

Bubbles from hell Hi all! Well, after about 3 months of reading your site to find answers to the many questions I've come up with in putting together my 75 gallon reef set-up,  I've got a question that I can't find the answer to anywhere.  The only hope of getting an answer to this question, I believe, is if there is some funky aspect going on here which will be familiar and immediately recognizable to more experienced aquarists.  I have bubbles from hell in my tank coming from my return pipe.  I've read all of your "I've got bubbles" posts and responses.  These are not standard, "you've got an intake leak . . . find it and seal it" type bubbles, these bubbles apparently exist independent of air and physics.  I have a 35 gallon sump with a PM bullet 100 skimmer.  Irrelevant since the sump is BUBBLE FREE at the point of intake to the return pump.  I've checked this with a magnifying glass and even run specially designed "air releasing" pipes into the sump from the tank drain. I've pulled the skimmer. The bubble aren't coming from the sump.  I started out with PVC from the sump to the pump with flex tubing right at the pump intake fastened with hose clamps.  I've reconfigured the intake pipe shape, length, etc. . . and even removed the hose clamps by hard lining the pipe right to the pump . . .with a no washer connection, just a coupling that has threads (to the pump) on one end and receives the 3/4" pipe cemented directly on the other.  That line is air tight and solid!  Pretty much the same story on the return line to the tank.  Thought it might be a venturi so I removed all flex tubing, quick connector and a ball valve.  It's solid 3/4" PVC from pump to tank.  That leaves the pump.  I took the main cap off, examined the washer, etc and tightened the screws which seemed a bit loose when I removed them.  Still had bubbles.  The pump btw is a 1200 gph Gen-X.  I have the exact same pump running my skimmer.  I switched these pumps to see if maybe it was something I wasn't seeing when I took the first one apart.  Still have those damn bubbles even with the second pump.    The possible key that hopefully one of you may recognize is that the bubbles at this point come in "waves".  While there is a constant stream of some very tiny bubbles coming from the return pipe, about once every three minutes, a pulse of TONS of bubbles will burst from the pipe.  They stick on the rocks and on the back of the tank. They are hugely apparent under the metal halides. They smoke my cigars and drink my beer.  They kick my dog.  I hear them laughing at me when I walk into the room. I want them punished in the most painful way. The tank has 85 lbs of live rock, two fish, lots of snails, hermits, 1 coral banded, 2 peppermints, 2 sand sifters, 1 brittle star.  It's a very fine white sand bottom.  I really want to begin adding corals, but I don't feel like I can proceed until this is resolved.  Any suggestions?  Am I missing something? JIM <Hmmm, I suppose the Gen-X has a 3/4" inlet or even 1", but I'll bet it doesn't really put out 1200 gph with 3/4" pipe (inlet), and thus produces what would be known as *cavitation*, like a boat prop that can't get enough water to drive in and thus, sucks air. Increase your pipe size and bulkhead to keep up with your pump. Any valves should be after your pump. With such a valve you could turn down the output to test the cavitation theory. With it turned down the pump won't need to pull in as much water and thus shouldn't cavitate, or produce bubbles. Hope your dog is alright. You can always buy more cigars and beer! You should get the last laugh!  Craig>

Overflows in Glass Tank Hi to all and thanks for the answer Anthony, I have the 55 gal corner bow tank Aqua C Remora, and magnum 350 canister Here is a picture so we are on the same page. I did all the things new fish keepers do and bought everything without any research.  That was a year and a half ago.  I built the Cabinet as well as a matching one in another corner with a TV on it.  Maybe some day that will get a matching tank on it after I throw a brick through the TV haha.   We are currently going to add a DSB (in the trashcan to the left) and live rock (in another tank).  I have discussed an upstream refugium  and the wife doesn't like the idea of another tank on the wall.  She dislikes it enough that she has given up on having the Green Mandarin.   I want to put in a sump in the cabinet below and a 20 gal high will fit nicely.  That way I can hang the Remora Pro down there as well as the heaters.  Are there any other reasons that a sump is a benefit (to convince the wife hehe)? <Hiding all of the heaters, pumps, powerheads, etc in the sump makes the tank look cleaner and less cluttered. The added water volume stabilizes the system and allows you to make water changes, supplement etc. in the sump. Much easier!> If I do put a sump it seems like I would need to drill the tank.  The bottom is tempered glass so that is out, but I could drill the back.  Could you please explain how to determine the height of the hole so the 20 gal does not overflow when the power goes off. <The hole should be several inches below the desired water level, a 90 degree ell threaded/glued into the bulkhead turned UP to the surface. Insert pipe into ell as long as needed to place top of pipe at the desired water level, minus about 1/2 for water to flow over the top of the pipe. IOW, the water is pumped into the main from the sump, UP to the top of the overflow pipe, and then when it overflows the pipe it drains into sump. If pump goes off, the water cannot be pumped over the top of the pipe and it all stops.  Make sure you put siphon breaks in your *return line* so they don't siphon in a power outage as well. Ask your local glass supplier about drilling glass.>      Also what size and how many would you put in this tank?  There are so many different schemes for doing this that my head is killing me. (could be the Guinness though).  You have really helped us out in the last six months since finding your site so I really wanted your advice.  This seems like the time to do any modifications since is nothing in the tank. Thanks for your help  Bryan and Dana Flanigan PS sorry this is so long.  We are stuck at home in this blizzard with nothing to do except yell at the kids and dream of ways to spend money on fish. <Depending on what you want to keep, 10 to 20 times turnover is needed. So, from 550 to 1100 total turnover. The WWM sponsors sell overflow boxes that are flow rated with various pipe sizes, head over to one of the sponsor sites and size your overflow bulkhead(s) according to these flow rates/pipe sizes. Oversize by a safe factor. IE: I would likely go with a 1/1/2" overflow in case I want a closed loop circulation system in the future or if increased flow rate is desired with growth, change of plans, etc. I suggest over-sizing plumbing by one or two sizes to allow for adjustability/growth.  Best of luck!  Craig> 

Bulkhead placement and noise 2/16/03 Hi guys real quick one.  I have 2, 1.5" bulkheads drilled in the top back of my 75 gallon tank.  I decided to add a glass overflow (like Anthony describes in his book) about 1" wide along the entire back of my tank.  This has been siliconed and really looks good.  So I filled my tank up (again) w/ tap water to test everything out.  Well....I don't think the overflow works quit like I hoped.  Don't get me wrong, it pulls a sheet a water directly from the surface, and works great w/ a simulated power outage, but the problem is the water going into the bulkheads. I don't know how I thought it would work, but here is my problem.  As the surface water runs over the overflow there is about a 1-2" space at the top of overflow where there is no water and the bulkheads are sucking the water in, in fact the very top of the bulkhead is not in/under the water so I am getting a sucking noise.   <if I understand correctly... the top of the bulkheads are actually slightly higher than the top of the overflow? If that's the case... no worries... drain the tank slightly and silicone an extender piece of glass to the overflow> I have been told b/f that this could be from a pump pushing more than the bulkheads can handle <almost certainly the case... not a problem even with your high placement of the bulkheads... that has nothing to do with creating a siphon> (pump is CSL velocity T4) but I have tried turning down the return w/ a gate valve and it doesn't help (turned the flow almost off even). <Doh! you fit the bill, bubs. A common problem where aquarists don't drill enough holes or put too large of a pump on. The ratings for bulkheads are a joke. What they can run under pressure (or creating a noisy siphon like you hear) and what will run safely and quietly (half filled pipes) are two very different things. The common 1" bulkhead is rated at 500-600 GPH per hole. But at that rate... it is noisy as all get out! 1" bulkheads really should only handle about 300 PGH each to be safe and quiet. Thus... to run a 1200GPH pump, you need 4 bulkheads! With your 1.5 inch holes... I'd guess you could only run about 1000PGH trough them quietly. If your pump is pushing more than that... you have your answer IMO> I always read that the best way to have tank is drilled for bulkheads, instead of built in overflows w/ bottom drains to pump.   <not much difference in flow here... just noise (the floor holes/towers are much louder)> But it seems almost everyone has these and builds a Durso standpipe and everything is quiet.   <this is just an engineering issue, my friend. Holes drilled on the back wall and sized correctly for the pump do not require a modification like the Durso. You just don't have large enough holes/bulkheads> I don't have this type of set up, my tank is drilled on the back w/ bulkheads and I can't hardly find anything about how to get flow from the tank/bulkhead to the sump and the quietest way to do it ( Nightly I read over WWM, reef aquarium guide, reef central and reefs.org) Please Help.  I'm ready to get the tank going again but have been dealing w/ this issue for about a month or so.  I might even rip the overflow off and try 90 degree elbows again and try to rig something else up.   <will not solve the problem bud... cut that pump flow back to 1000GPH and you hear it quiet down> I even tried the elbows b/f, but again had a terrible sucking noise, and yes tried turning the pump down, still did not help.  Any suggestions, I'm just feed up.  Thanks Bryan   <no worries bud... a miscalculation. Easily corrected. Best regards, Anthony>

Water Flow Hey Boys! <Good evening.> Thanks for the fast responses to my last 2 inquiries!!  U guys rock! As stated before, I'm setting up a 135 (Long) tank and originally purchased a Dolphin 2100 pump which I was going to mount directly under the return for a straight shot into the tank at about 4ft or less distance.  Since surfing, I have read much bad press about the Dolphin pumps and their seals leaking on the newer models, most figure it's due to mass output and poor quality control.  Anyways, I am now thinking of sending back the Dolphin 2100 to get an Iwaki or any other well recommended QUIET pump, but I can't find an Iwaki that gives me the throughput of the Dolphin? <Iwaki makes them, they're just not stocked everywhere... you might see if one can be ordered for you - or... consider two with separate lines running to the tank.> At about 2100 GPH from about 4ft below I was counting on excellent turnover and current flow in the tank.  Now what do I do to get that high current flow from a more reliable pump? <You have options...> Again, hat's off to the best. <Cheers, J -- >

Plumbing/Circulation I'm in the process of setting up a 150g using a Dolphin pump as a sump return and hoping to get around 2000gph. I'm going to use 1 1/2" flex pvc tubing from the pump up to a Y connection just outside the tank. <There may be a manufacturers recommendation for plumbing size, follow it for max performance.> My question is whether to reduce down to 1" or 3/4" coming out of the Y to serve as the manifold. 1" pvc has quite the outside diameter and will probably be hitting the water line or be below it if I suspend it from the top of my acrylic tank and I'm thinking it may not create enough pressure to get good circulation out of the flared nozzles, on the other hand I don't know if 3/4" will restrict the flow too much. I'm also unsure of how many and of what size T connections to use feeding into ball/socket tubing. My hope is to have six individual outlets from the manifold. Any helpful input would be appreciated. Thanks <Look up flow rates of the pipe sizes in question at the pressure the pump delivers. Then match these to the capacity of the pump and return plumbing sized slightly larger and adjusted with valves (the ball/socket tubes can be stepped down from 3/4" to 1/2" and they have valves to create velocity if needed).  You can always step down, but once you plumb with small pipe, you're done. Go with the larger pipe if possible/needed, but add valves to help with velocity. The tee's are the same size as each side of the manifold (off the Y) and the number needed depends on flow rate of pipe at given pressure. Plumbing/pipe sites will have this info.   Hope this helps!  Craig>

Lost Emails and Pipe Sizing Don't know what happened to my e-mails but received no response, so here goes one last try. <We didn't lose you Scott, we get a lot of mail to answer!> 150g tank, dolphin return pump, 1 1/2" tubing from pump to Y fitting, hoping to get 2000gph using six nozzles off of manifold along with three 1 1/2" overflows. Question is what size pipe to reduce to coming out of the Y fitting to serve as the manifold , 1" (with 3/4" nozzles) or 3/4"(using 1/2" nozzles). Thanks for any help. <Total flow rate of six outlets needs to total 2000gph or slightly more. Use plumbing sized to accommodate this. (Pipe has a known flow rate at known pressures).  I don't keep these floating in my head, but they are to be had on the net (flow charts at plumbing manufacturers, etc.). My own feeling is 1 1/2" pipe will be reduced too much with two 3/4" lines, no matter how many outlets they have. I would go larger and step down as needed or w/valves on flex/ball fittings.  Craig.>

75 gallon circulation alternatives Richard Durso to the rescue!! http://www.rl180reef.com/frames.htm <There you go! Leave it to someone that has dealt with this problem!> Thanks for confirming my circulation (lack of good) options research. Have done a ton of reading on your most excellent site. I did see some different opinions among the crew on pressure rated or non-pressured rated return pumps. Of course I agree with the folks who support my pump choice. I have chosen to turn the 3/4" return hole into a powered closed loop, just like my hero Richard Durso. He did not just increase the gravity flow out of the overflow using the second hole for a standpipe, he is sucking directly from the tank thru an elbow. I have faith in the solutions but I have more then a little confusion also. I will be buying an external non-pressure(?) pump for the closed loop; lots of info on your site on brands. My confusion is on how pipe size is related to flow. <All is well with above as these are two separate systems, one using gravity to feed sump, etc. and the other closed-loop. This has the same water dynamics as the return system, without the head considerations (closed loop can be zero head), just head/friction/backpressure from plumbing restriction. If you use a pump with a 3/4" inlet to match the tank plumbing restriction, and enlarge the plumbing as soon as practical, the rated flow will likely be realized...remembering oversizing pumps to factor in plumbing restriction.  See flow rate charts on various pumps for sizing pumps for return and closed loop.> The pump sucks water at a given flow rate, matched to the output (duh). <Yes, but only what it can "pull", what goes out, must come in first, or we have cavitation, just like boat props, and lack of drive, or in this case, pump output. Even though most pumps use various sized inlets and outlets, they are all designed to be plumbed to larger pipe than the pump inlets/outlets.>   Velocity of water must vary as the diameter of the pipe changes. The bulk head size limits diameter there, but you and Durso seem to like bigger diameter pipes in other parts of the line [you said "Also use larger pipe throughout, you won't be disappointed.>"] Shouldn't I use 3/4 throughout? I am assuming that a pump with a 1" inlet would be toooo big. <NO! Go larger for both inlet/outlet and then step down at inlet(s) to 3/4" - 1/2" This provides oversized inlet capacity and the output is valved to supply velocity you desire. Just use the pump that moves the amount of water you want to move, with a healthy reserve. You have a 75 with the overflow *and* the closed loop. The closed loop could be plumbed to a Mag 7 (1/2" in and out") and almost get 700 gph from it alone, with a 1" - 1 1/4" manifold.> It is this necking down then expanding that is hard to visualize. I can see how gravity and atmospheric pressure limits flow thru the overflow hole, but can a non-pressure pump suck huge flow thru a 3/4" ID bulkhead? <If the pump has a 3/4" inlet, then it should work as intended, as long as the 3/4" restriction is as *short* as possible.> Anyway to engineer the pump rating or just go big and use a gate valve on the outlet side? (see I did read the FAQ) Can I talk about engineering and still use the word suck to describe what is happening? <Oh, absolutely!  Just use the flow rate charts all the pump companies provide (perhaps use the head chart on Reef Central to figure backpressure/head from plumbing restriction) and then slightly oversize pump and use a valve (you will want to do maintenance too) to control flow as desired. You are on the right track.  Craig>

Overflow capacity Hi, I was just wondering if you happen to know what the max rate (gph) a prefilter can handle with a 1" tube at bottom of tank, as far as how many gph pump could I use w/out overloading. I was thinking of a little giant pushing 1000 @ 3'. <A 1" overflow pipe will not handle 1000gph, better surf over to one of our sponsors and look at what flow 1" overflow boxes will accommodate. Foster and Smith carry CPR overflows with 1" pipe that have gph flow rating.> What external pump in your opinion is the most quite for an external pump. Thank you for your help ! <Iwakis (Japanese, not American) and Custom Sea Life are popular quiet external pumps. You will need the overflow capacity to handle these!  Craig.>

Microbubbles Hi Bob: I'm a bit confused with regards to the term "Microbubbles" are these the same that are produced by my venturi skimmer?  They are smaller than those produced by an airstone (which I unplugged due to salt everywhere) but not to fine to see easily enough - they fill probably 50% of my tank - I hope they're not dangerous because I can't seem to do anything about them - I only run the skimmer at night now but it pulls very little skimmate that way. My thinking there is at night the fish are in the rocks where the bubbles don't penetrate. <Is this a new tank and skimmer? If so this will go away in time. Sometimes bubbles are caused by high wastes (only running the skimmer at night is BAD, run 24/7 no matter what) or improper water chemistry/ionic balance/pH. Check these too. Also, if the skimmer is pushing too much water through and destroying the dwell by pulling the bubbles through the skimmer and into the tank, adjust the pump/skimmer to slow down the flow, increase dwell/contact time, and reduce bubbles by floating them out where they should....in the skimmer cup.> I even tried hanging a bag of Chemi pure under the exhaust of the skimmer to dissipate them a bit - no avail. then I turned a powerhead at the exhaust and this created a bit of a "whirlpool" effect and kept the bubbles at one end. but are the bubbles themselves really the problem or the amount of oxygen they create in the water?  (By that I mean that the oxygen levels are the same regardless if the particular area is suffused with bubbles or not because the oxygen is dispersed equally?) David <The bubbles are a problem for fish because they can act like the bends in humans, forming bubbles in their flesh or systems that are as problematic as they are for humans. Do check your skimmer set-up/adjustment and water chemistry to find out why you are getting so many bubbles.  Craig>

Plumbing and pump help please? WWM Crew, Are there any good resources that you can recommend for plumbing a marine system? As I am not a plumber and don't have anyone local that I can count on for solid information, I don't really know where to start. I am having a hard time getting enough information to make an informed decision on how to proceed but really appreciate you taking the time with this n00b and my seemingly endless questions. It seems for every question answered that the answer generates five more. Thank you for your time and patience. My tank will be predrilled for 4 bulkheads. 2 2" and 2 1.5" bulkheads. I had planned on running the 2" (outputs) to the sump with 2" flexible PVC. To return from the sump I had planned on using a Magnum 12 to return to the 2 1.5" bulkheads with a 45" on each of the inside bulkhead's to disperse the flow. Now most of the pumps I am looking at have a 3/4 discharge line. How do I plumb that so I end up with 1.5" line at the bulkhead of the tank? Is it better to run a single 3/4" line that would tee off to two separate 3/4" lines expanding from 3/4" to 1 1/2" right at the bulkhead or is it better to create a manifold or T directly after the pump discharge fitting with two 1.5" lines to return to the bulkheads? <It's best to go with 1.5" pipe manifold, split into two 1" lines and 1" bulkheads would be fine, no need for 1.5", depending on flow rate/size of tank (10-20 times turnover). Perhaps see plumbing flow rate/head calculator on Reef Central.> Thank you for the advice on the closed loop. I think I will use 4 3/4" intakes that go to a manifold directly before pump (again seems these pumps all have intake and discharge of 3/4") and then another manifold that splits into 4 3/4" lines. Will these manifolds cause any issues as I am converging so many lines before and after the pump? -- Would it be better to have a separate pump for each line? <Not necessary, but do go with a much larger manifold. You will notice the flow rate of Mag-Drives are dependent on using the prescribed plumbing size which is up to double the size of the pump outlets. IE: Mag 18's and 24's have 3/4" and 1" outlets yet call for 1.5" outlet plumbing. Go to Lowe's or Home Depot and purchase a 1.5" slip union or slip valve and a 3/4" to 1.5" threaded reducer, then run 1.5" or 2" pipe from there up, then reduce to the return size of 3/4" or 1".> Thank you ever so much! The ReefN00b <Go with larger pipe when in doubt!  Hope this helps!  Craig>

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