To Flow or not to flow 9/13/04
Hello to the WetWebMedia Crew!
<cheers :)>
You have been so helpful with all the other little bumps I have hit I decided you would be the first people I ask for a recommendation on flow improvement. I have an 80 gallon AGA 48"X18"X21"tall and I am upgrading it to handle SPS.  I currently run a MAK4 (1120 GPH-head loss-SCWD loss=?) from my sump to a SCWD (squid) up to two sets of Loc line jets on each side of the tank.  The flow was fine for softies but I worry it will not be enough to keep my SPS happy.  
<agreed... garden reefs need about 10-20X water flow... but SPS tanks generally need a minimum of 20X. So... your 80 gallon tank needs at least 1600 gph... closer to 2000 gall would be nice>
I have considered a spray bar but have heard stories of frequent cleanings and increased backpressure leading to burst return pipes.  
<true>
I was wondering What you would recommend to boost/maximize my flow?   
<please do check out: http://wetwebmedia.com/pbh2oret.htm>
Do you recommend Sea Swirls?  
<yes... they are very fine products>
If I could avoid another couple hundred dollars in pumps that would be sweet as my new hood broke the bank!  Any suggestions would be much appreciated!
<the above link is a very inexpensive and effective means of delivering water flow. Best regards, Anthony>

Flow rate
Is flow rate of a tank determined by the return pump?
<To the largest extent, yes>
I know that in order to keep the sump at a certain level, the drain line to the sump has to be larger than the return line, for example, a 1" drain with a 3/4" return.
<Yes> |
If this is true, does installing a pump with a larger flow rate increase the flow rate of the aquarium?
<Can, should, yes>
What is the recommended turnover rates for different types of aquarium setups?
<As a general "rule of thumb", more is better... ten, twenty times turnover for most all>
Thanks for the info. I am getting tired of working in my trade.
It has become very stressful and I do not enjoy it anymore.
<Very sorry to hear... but glad to realize that your awareness>
For the past 7 years I have been gratified with my aquariums and have been doing much research online with things pertaining to this hobby. In the past year I have been thinking of performing a slow (a little at a time) change in career to designing  and constructing acrylic aquariums, refugiums, wet/dry filters and terrariums. I  know I can do it and I know I would love it.
<Outstanding. Welcome to our trade. Bob Fenner>

How much water flow for a 72 gal?
Adam! Thanks for your response.
By 20L, I meant a 20 gallon long aquarium. Sorry for the confusion. << Okay, that sounds better. >>
Since then space constraints have limited me to a 15g refugium. Isn't 800gph in a 15 gallon refugium too much? Shouldn't I keep the flow low? << Well you don't want the water blowing all your algae around in your sump.  But on the other hand the refugium only helps out because it is connected to the main tank.  So to get benefits from it you need that water turning over. >>
BTW, I just ordered a Tunze stream 1600gph pump. I'm planning to have two Seio 620s on one end and the Tunze at the other -1600gph meeting 1200gph somewhere near the middle of the tank. The Tunze has a 2" outlet, and the Seio's 1.5" outlets. As a result the output velocities will be close.
I could use the Mag3 from the Remora Pro to pump water from the refugium to the display. With a 4' head it's good for at least 200gph, and the skimmer can be powered by a Quiet one 3000 rated at 780gph. << Sounds good. >> I hear these pumps don't like back-pressure and tend to overheat. Any truth to that? << All pumps have that problem, but if you are restricting the output and not the input I think you'll be fine. >>
This will result in a total flow of about 3600gph for a 72G. Is that too much for just Xenia and Capnella? And the fish? I worry about the clown...
<< You can never have too much flow. This sounds great. >>
Thank You for your time!
Narayan
<<  Blundell  >>

Water Movement For Acropora
Hello,
<Hi there! Scott F. here today!>
Do Acroporas do better with a direct flow of one power head or with 2 - 125gph Power Sweep power heads? I have a 10 gall nano reef tank with 1 Acro with plenty of room for more! What do you guys think? Thanks for your time!
<Well, most of the Acropora that favor high flow will benefit from randomized, indirect flow. Laminar flow directly into a coral can literally peel the tissue right off of the colony. Better to use those Power Sweep powerheads, or even some sort of rotating return device, like the wonderful Sea Swirls! HTH! Regards, Scott F.>

Skimmer flow
Bob- could you tell me if a protein skimmer water movement adds to the flow rate of the reef tank. The skimmer is out side the sump with a external pump 700 gph.         RGibson
<I'd say yes... and would like to add a proviso... that there is MUCH more flow in the wild in most all settings than anything a hobbyist supplies... Practically speaking, w/o sucking up or blasting your livestock against a tank wall, there is no such thing as "too much" water flow. Bob Fenner>

GPH question.. 2/2/04 
What gph rating do you recommend for a 180 gallon tank? I'm going to have it "T" off to both returns from my sump, so its going to be one pump doing all the work. I plan on going with an Iwaki, and they have one rated for 1500 gph and 2000 gph @ 4ft. Any good advice will be greatly appreciated... 
<As a general rule, total water flow should be 5x the tank volume for a fish only tank, and 5-10x or more for a reef tank. The problem you may encounter is weather your drains will handle such high flow. You may have to choose a smaller return pump, which has other advantages such as less noise, less power consumption, and lower cost. You can make up the difference with powerheads or closed loop circulation. Hope this helps. Adam>

- Too Much Turnover? -
Bob,
<JasonC here in his stead...>
I am having a slight problem with a recent ocellaris clownfish I just purchased, he seem to have a difficult time swimming in my tank with the current. Do I have too much turnover? This is what I have as of now:
2 maxi 900s - 230 gph = 460gph
1 penguin bio wheel = 330gph
for a total of 790gph. I have a 46g bow front with 50# of Fiji live rock. that is a turnover of right around 17.1x an hour. but my major questions are will the clown be ok? <I think so... give it some time to 'get in shape' as it were...> looks like he is struggling at times. <Some of that is just due to the way they swim... seem to be struggling but in fact they are not.> great color to him, he is eating. Will I be ok if I turn my BioWheel off until I get my skimmer? <Uhh... I wouldn't, think this does provide some of your biological filtration... would leave it running.> When I get my skimmer I plan on taking the BioWheel off the tank anyways. will my live rock be enough filtration for now until I get my skimmer? <Perhaps, but not something that I like to see happen suddenly... perhaps take the wheel itself out and let sit submerged inside the tank somewhere in case you need to get it running again soon.>
thanks
Tim
<Cheers, J -- >

- Circulation Question -
Hi Folks:  Thanks for all the great info on your site.
I'm new to the hobby and have been voraciously reading your words of wisdom.
I have a 58 gallon FOWLR that is 8 weeks old, filled with 50lbs of live rock and 4 fish (2 YT Damsels, 1 Clown, and 1 Yellow Tang).  I have a 20 gallon refugium underneath with a Mag 2 pumping 125gps back into the tank (when factoring in the height.)  This week 2 fish died with what looked like tail rot and I'm concerned that a purplish algae growing on the rocks and sand is Cyanobacteria.  I've been feeding with a pinch of flakes in the morning and 1 cube of frozen food at night, but have now backed off to 1/2 cube at night.
After reading your many articles on circulation, I've realized that my circulation is woefully inadequate and may be the source of my problem, so I added a Maxi-jet 1200, pumping 295gph.  I am also considering changing my refugium pump to a Mag 7 as advised by my LFS, which would pump 480gph at the given height. <Hmm... or just some more circulation in the tank... would allow the refugium to stay more of a refuge than a sump if you left the pump you had. You could easily get two more of those MaxiJets in there.>
I am concerned that I am overdoing it on the circulation. <Nah...> Since I added the Maxi-jet, the fish are now hiding in rocks and caves and only come out at feeding time. <Could be for other reasons, but give them some time... I think you will see the fish actually like it. Am circulating roughly 1800 GPH in my 55 not including the return... should be no big deal.> Should I replace the 1200 with a lower powered model, or is this just normal behavior where the fish just need time to get used to the increased circulation? <It's a bit of a surprise at first, I think... but they should adapt to it pretty quickly.>
Thanks,
Ken
<Cheers, J -- >

Water Turnover
Hello all, wow it seems like you guys are getting more and more questions every day!!! My question is about water turnover. I read that water turnover for a reef tank should be between 15-20x. I just wanted to be clear that what is meant by turnover can include powerheads so if I am running 2 powerheads, 1 @ 175gph 1 300gph and a protein skimmer that has a powerhead that runs @ 295 gph for a total of 770 gph in a 46 gallon tank I would satisfy that requirement. I just wasn't clear that what is meant by "turnover" only meant a sump system where the water was leaving the tank and returning. <Cumulative, all movement in the tank, so your figures are correct. Although, you may have to add movement to a 'spot' to help with algae/detritus control, Don> Thank You. Angelo

Closed Loop Flow rate
I did go to RC and enter the params... all it said for a result was that I have 7 feet of head pressure.  They even broke it down to 6 feet from the 90-degree elbows and 1 foot of actual height.  But this would imply no flow for my system.
<If you have flow, there must be one or more of several things happening:
Actual head height is not as much as assumed, pump output is greater then assumed, less actual plumbing restriction than assumed.>
Side question: I have the pump submerged in the tank about 1 foot below water level, then water goes out over the rim of the tank, down about 8" to accommodate the SQWD and then back up over the rim and into the tank.  Should I consider any head pressure from this arrangement from the 1 foot up (assuming the 8" up and down will cancel out) or does it just have to do with the water level in the tank (i.e. about 2" of head to get over the rim of the tank)?
<Actual head height would be less than 10" as the 8" doesn't  "cancel out", but it isn't a straight 8" head either. Pump depth and only pushing 2" over rim also changes equation in pumps favor.>
If I don't need to include this in the calculations then I come out at about 6 feet of head pressure, and the pump is rated around 320 g.p.h. at that point... that would explain it.  Although it seems like more flow than that... it's really hard to tell.
Jeremy
<There you go. Hard to judge from there without a flow meter.  Craig>

Too much water flow?
<Hello again Luke, PF here with you tonight>
I'm wondering... is it possible to have too fast water flow in the tank?
I currently have 2x 150 power heads in 20gallon tank. The water is pretty agitated. <Well, you're turning over the tanks volume 15 times an hour, no surprise there>
I have 2 small clownfish in there.
Could the water current be too strong for the fish? I currently have no corals in the tank.
<Well, unless the fish are being dashed about on the rocks, or are always struggling, I wouldn't worry to much. You can always swap them out for something with less power if you're really worried.>
Thank you,
Luke
<You're welcome, have a good evening, PF>

- Flow Rates -
<Good morning, JasonC here...>
I have enjoyed reading all the post and helpful answers as well as Bob Fenner's recent book.  I have a question about plumbing a 65 gallon reef tank.  First how can you determine the drainage capacity of a particular size bulkhead? <Somewhere, there is a formula but for the life of me I can't recall at the moment - if I recall, 1" is capable of 600 GPH, so 1.5" will be much more so.> I am thinking about using two 1.5" overflows in the upper back wall in one corner approximately 3" apart and enclosing them in a full size (tank depth) overflow box to increase surface skimming capacity.  The box would fill and then empty via the 2-1.5" overflows into the sump.  Does this sound feasible? <Sure.> From the sump inlet side I want to feed the skimmer then into the clean side and back to the tank via one pump.  Also from the sump inlet side I want to go directly back to the tank with one pump and split into two returns for basically a closed loop circulation as I would rather not use powerheads.  How does this sound. <Feasible, but you might want to at least feed the skimmer and closed loop from a settling chamber in the sump - water coming from the tank will have a lot of air in it which will make the pumps cavitate and in turn be less efficient and noisy to boot.> One of the most confusing parts of setting up my first reef tank is the plumbing to provide adequate flow and circulation. <I think you are on the right track.>
Thank you very much for any advise.
John
<Cheers, J -- >

Water flow question
I am currently setting up a 300g L.R. and aggressive fish tank. I have been keeping tabs on your Q&A section and have noticed a lot of reference to water movement. Now I find myself questioning my own set up. Here is a rundown on what I have planned so am just wondering if my flow will be adequate; 4 hundred lbs rock, to 8 in sand,55g sump with circulation disrupters (pc.s of acrylic sideways) chiller of course, second 55g sump with app.2 mangroves and mud bottom with app.900gph flow, the main tank will have 4200gph return flow with 4 additional 700gph wave generators inside to make sure of no dead zones. Does this sound adequate or should I even shoot higher. PS. AND YES THERE WILL BE TWO SKIMMERS DOWN FLOW OF THE MANGROVES. Mahalo from Maui Bill
<Aloha, Bill! It sounds like the water flow in the display will likely be quite fine. The old recommendation of 4 to 10X tank volume is dead. Modern aquaria with large live rockscape if nothing else negate that. 10X per hour is a minimum... reefers and tanks with aggressive/messy feeding fishes like your should be closer to 20X of random turbulent flow. The only thing I would do different here is lose the wave generators. Run straight flow in a random turbulent pattern... Far more effective. The bottom line is that we want no dead spots for detritus to accumulate... all should be kept in suspension for skimmers, etc. No worries here about excessive flow as long as linear/laminar movement (one-directional) is avoided. Further info here: http://www.wetwebmedia.com/circmarart.htm
Best regards, Anthony>

Water flow
I am currently setting up a 300g L.R. and aggressive fish tank. I have been keeping tabs on your Q&A section and have noticed a lot of reference to water movement. Now I find myself questioning my own set up. Here is a rundown on what I have planned so I'm just wondering if my flow will be adequate: 400 lbs LR <Great!>,to 8 in sand
<Do you mean 8 inches of sand? IMO this is too much for a FOWLR tank. Have a thin bed an inch or less and you won't need to worry about it becoming a nutrient sink. Nitrates are not that big of a concern for your tank...nitrates are totally undesirable in a reef tank.>
55g sump with circulation disrupters
<For this size tank, I would want a bigger sump. Many people like the sump to be around 30% of the tank volume. This would put the sump at about 90-100 gallons. This will add flexibility to your tank and make overflow of water onto the floor much less of a possibility.>
pieces of acrylic turned sideways
<called baffles>
chiller of course
<Is there a specific reason for this addition? In reef tanks, chillers are needed because the intensive lighting produces lots of heat that raises the temperature of the water. You will not want intensive light for this setup because of high nutrients from messy feeders, etc. Intensive light for this type of setup will most likely cause a hair algae nightmare.>
second 55g sump
<55g + 55g=110 g. The two sumps will be adequate. The second sump like the one you are describing is commonly called a refugium.>
with app.2 mangroves and mud bottom with app.900gph flow
<You will need much less flow through the refugium. A refugium is a place with gentle currents.>
the main tank will have 4200gph
<Acceptable>
return flow with 4 additional 700gph wave generators inside to make sure of no dead zones.
<Okay>
Does this sound adequate or should I even shoot higher? <Sounds good. No complaints from me.>
PS. AND YES THERE WILL BE TWO SKIMMERS DOWN FLOW OF THE MANGROVES. <Fantastic! Don't skimp on the skimmers! Spend some of the money your going to save from not buying the chiller and buy really good skimmers like Euro-reef or similar brand. With aggressive fish (big, messy eaters) you're going to need the best filtration possible.>
Mahalo from Maui, Bill
<You're welcome! Please peruse the WetWebMedia website for this and much more information about saltwater aquariums. Knowledge is power! David D. in sunny Las Vegas.

Water Flow Rates
Dear WWM,
I kept marine fish in the 60's and early 70's and am currently in the process of "getting up to speed" in preparation for a reef tank.  I have spent much of this prep-time on your very helpful web site and am looking forward to your new book.
<I can tell you the guys are ready to finish it too!>
My question(s) have to do with figuring out water flow rates.  I have not purchased any equipment yet, just doing a lot of reading.
<Very good!>
If (for this example) I had a 110 gal tank and am planning on a back drilled overflow arrangement using 1" ID PVC.  From what I have read it appears that one could estimate 600 GPH (per hole) to be gravity fed to the sump. My sump will be 22 gal. capacity, sitting 4 feet under the surface of the show tank.  The skimmer will be in the sump with it's own pump.
<Ideally the sump should be 1/3 the tank volume. Much water to account for....>
If I want say 12 times the capacity of my tank to flow through the sump and back to the display tank. 110 gal x 12= 1320 GPH. Should I drill (3) 1" ID holes for my overflow (1800,GPH) and use gate valves above the sump to adjust the overflow rate into the sump?
<The reverse of this. Unrestricted overflows from display to sump, valve on pump (sized as you suspect) to control flow rate to display.>
Put simply, is it only a matter of selecting the right return pump (factoring in head pressure etc) to match the overflow rate from the display tank?  (I have visions of my sump looking like a swirling mass of water rushing through, sweeping sand and LR all around)!
<Yes.  Use a partition or small plastic bucket/pvc fittings to control the currents. It is best to oversize the overflows like crazy (If they call for 1" I use 1 1/2").  The flow rate is controlled with a simple PVC gate valve directly behind (inline) with your pump, sized to account for head height, plumbing restrictions, etc. There are no valves on the overflows, they flow freely by gravity to a section of the sump and perhaps filter bags.  I have my doubts if 1" pipe will carry 600gph passively (gravity fed). I advise over sizing overflows/bulkheads if at all possible or using more than anticipated.  Also, purchase bulkheads first, they require larger holes than the pipe ID, drilled with a hole saw.>
I know I also need to position my overflow near the surface.  What "formula" do I use to figure out how many gallons will go down the overflow (based on the height position or actual water intake level of the overflow)  in the event of a power failure? i.e.. a 1.5" drop in the water level of a tank that is 48"x24"x 25" will work out to be "X" number of gallons draining into my sump.
<You don't. You put the top of the overflow 1/4-1/2" below the water level you want to maintain in the display (making them adjustable is a good idea) fill the tank to the top of the overflows and then fill your sump, leaving a little room just in case. MAKE SURE THERE ARE SMALL 3/16" HOLES DRILLED IN THE RETURN LINES (the pumped line from the sump to the display) JUST BELOW THE SURFACE OF THE WATER of the display (the level desired in the display while running) which would be the same level as the top of the overflows. These will allow air in to break the siphon in the pump/return line as the water level falls so the tank doesn't siphon the tank to the bottom of the return lines, but stops at the top of the overflows. If the power goes out now, the water will only refill the sump to the original non-running fill level.>
One last question, for now.  What is the ideal water level in a sump (more specifically, in a 22 gal. sump should I keep it approximately 1/2 full, 3/4 full etc leaving some, yet to be determined room, for the overflow in the case of power failure)?
<Fill as above. If care is taken to stop siphoning below the overflow level, the sump can be filled say 3/4 or slightly more when the system is not running. When it is turned on it will use more water in the system, but can only return to the former, non-running level, not overflow. Does this make sense to you? It's important you understand.>
Thank you much for your time and interesting reading. (This is not something that was a possible 30 years ago when I first started out, and now to have such a resource at my finger tips...it's great!) 
Thanks again, Cary
<You very welcome Cary, have fun!  Craig>

Pump Up The Volume!
Hi and thanks for the quick response.  I'm almost finished with my setup, but could use some clarification on 2 things:
My pump can put more water into the tank than the overflow can keep up with. I have a valve I can turn down to slow the pump: is that bad and will it overheat the pump by keeping this back pressure on it?
<Should not put excessive back pressure on the pump in a well-designed system>
I was also thinking of increasing the rate the water is drawn out of the tank by adding a straight siphon from the inside overflow box directly to the sump.  This siphon will still break if the power goes out, but won't start up again (like the U tube), so I would get a switch that won't turn back on after a power outage.  Is this a dumb idea? :)
<I don't think it's a dumb idea. Actually, since the straight pipe doesn't rely on siphon, it will actually restart when the pump pushes enough water to reach the top of the overflow. Personally, I think that this type of standpipe is much more reliable than an elbow>
How do other people balance the outtake with the pump power, besides adding more overflows or having less powerful pumps.
<I've seen people knock out skimmer box teeth to allow more water in, adding larger standpipes in the overflow to the sumps, etc. Lots of good ways for creative people to accomplish this. Do use the wetwebmedia.com chat forum, where you can connect with lots of other DIYer's.>
My Ebo Jager heaters say not to immerse beyond the indicated water line, but I know that some people still completely submerse them (horizontally) anyway.  Is that risky?
<Nope. Most people with sumps seem to use them in a horizontal position. By the way, the line on the Ebo's refers to the minimum water level that the heater should be immersed in when in a vertical position. Should be no problem horizontally>
Thanks again! Mike
<And thank you for stopping by! Good luck with your setup! Regards, Scott F>

Water Movement
Thank you for all the help received so far.
<You're welcome!>
When considering water movement, what counts as low, medium and high?
<IMO anything under 10x per hour is very low. Anything over 20x is very high. Anything in between is just about right unless you have an SPS tank>
In a 36 by 12 by 15 inches tank I have two Fluval plus 2 filters running all the time, one with coral gravel and the other with Cerapore. The filter containing Cerapore provides the most water movement. In addition I sometimes use a third Fluval plus 2 which contains PolyFilter and Rowa phos. With all three going, the seaweed sways gently. What water movement is this?
<Low>
What animals appreciate it?
<Many including mushrooms and bottom-dwelling fish>
Also I have a pearl bubble coral, Physogyra. This coral seems to be doing ok, but I have heard conflicting reports of correct water movement and light.
<Low to moderate current. Please feed this critter>
The coral is just more than half way from the top of the water and the metal halide is around 16 inches above the water.
<Might be better off in the lower level of your tank. It doesn't need really strong light. In fact, it may not fully expand in the presence of really strong light. David Dowless>
If it helps, the coral was green but has had sufficient light to turn brown. I don't know the type of bulb is in the metal halide.

Circulation for 840g
Hey Guys,
<Hello!>
Thanks for taking your time to read this and hopefully answer a couple of questions for me.  I'm working on the set up of a 840 gallon aquarium
<Fish Only?>
and was wondering about circulation.  I am considering using the Dolphin 5600 which as I understand is rated at 5600gph at eight foot head, the returns will be at a height of 7 ft. (the tank is 7'X4'X4' and the stand is 3' tall), I know this will only turn over the tank about 6.6 times per hour, will this be o.k.?  
<Maybe...as a bare minimum. I would want more circulation. Be sure that your overflows are large enough to handle the volume that you want to push through it. Otherwise, pump size won't matter. You have three options for increasing circulation: use powerheads (a dreadful idea), larger pump (not bad) or a closed loop circulation system (YeeHaw!) This is what I would do. A closed loop circulation system will require an additional pump but it really is the best idea. Plans for doing this abound on the internet. I want to suggest Anthony Calfo's book on Coral Propagation. Circulation will help you avoid algae and Cyanobacteria problems as well as contributing to the overall health of your tank. The fish will love the added water movement. Remember, these critters are coming from the ocean>  
I am really open to any other recommendations you could make on other pumps, but at the time I would like to use just one strong pump, and add smaller ones when finances allow.  Any other pumps you would rather use?
<A dolphin will do the job. When you need this much circulation, your choices are somewhat limited. Just be sure it is saltwater safe>
The second and third questions concern the plumbing.  The pump has 2" in/out-takes and I was planning on t-ing the return into 2 2" returns, one for each side of the tank, ( the tank is going to be viewed from the two long sides and one short), does this sound o.k.?  Any suggestions?
<I would want more returns within the tank. You will have very little circulation with only two returns. I would want the largest returns that I could find. You may even need to special order the parts. Only 2 returns at 2" a piece is too few and too small. Plus, there's no way over 5000 gph will go through a 2 inch hole>
Lastly, the drains in the overflow, I am planning to use 2" bulkheads but am not really sure how many should suffice, 3, 4, 5?  
<The more the merrier. For sure, at the very least one on each end and one in the middle. I would probably do 4 large bulkheads (as big as possible) spacing them evenly across the back of the tank. If noise becomes a problem, build a Durso standpipe...It will make the overflows silent>
Like I said, I am planning on adding at least one more circulation pump (2-3000gph) in the future so I guess I'm asking how many I should use for 8-9000gph turnover.
<That would be fabulous for the closed-loop plumbing that I was talking about. Do yourself a favor and get the Calfo book>  
Thanks for your time, and best wishes to all.
<It's my pleasure>
Carl
P.S.---Your website is a great resource to the hobby.
<Thanks. David Dowless>

Re: Current
Thanks for your help so far....this is the best site I have found for information on marine tanks.  I have a quick, easy question.  It's about current in the tank, and how much water current is sufficient.  First I'll explain what I have thus far.
The tank is 90 gallons.  48X24X18 (standard 90 gallon tank)  I have a mountain as I call it of live rock in the center of the tank, gradually leveling out to the sides.  All the rock is doing very well.  I'm still cycling my tank with the rock, 2 cheap domino damsels,
<don't tell them that.>
a convict blenny, and about 10-15 hermit crabs.  The water testing levels are all in check thus far.  Now for the water current dilemma.
I have a FLUVAL 404 canister filter that shoots current from one corner, I have my protein skimmer causing a waterfall type current on the other side of the tank.  In the center, I have a powerhead shooting current downward over the rock towards the front of the tank.  Both powerheads are moving about 295 gph and the Fluval is slightly more.  Is this too much current for the live rock in the tank? The fish seem to enjoy it but I don't want to harm my rock.
<Fear not, they are tough>
I have been told that the more current the better, but I just want to get a second opinion.  Also, would too much current harm the fish?  Eventually I hope to get a wave maker with several powerheads that change throughout the days.  Any information would be greatly appreciated.  Thanks in advance.  Happy holidays also. John
<Thank you, happy Holidays to you as well my friend.  May your holidays be filled with tanks, skimmers, sterilizers, rock, sand, fish, and all that fun stuff.  The more flow the better is correct, but there are different kinds of flow.  Save your money on the wave maker and check out the article below.
http://www.wetwebmedia.com/circmarart.htm
Best Regards, Gage>

Powerheads
Bob, a question about powerheads. <<Bob's not here, man. You get JasonC in his stead.>> I 46 gallon bow front marine tank. I have a Aqua Clear 300 on one side of the tank and I also have a Aqua Clear 400 on the other side of the tank. My ecosystem also has a Rio 600. The powerheads face each other to get a turbulence kind of effect and the Rio just agitates the surface. Do I need additional powerheads because of the bow front? <<I wouldn't think so - this seems like adequate circulation, but time will tell. If you find yourself fighting problem algae, then perhaps you might consider an additional powerhead.>>
Thanks <<You are welcome. Cheers, J -- >>

Re: Porcupine Puffer (actually water movement, pH: marine)
Anthony: Thanks for the help. 2 more follow ups. 1.) is there a source written or electronic which directs how much water flow different species of fish prefer. 
<good question, but no authoritative work that I am aware of. Much of it is anecdotal or inferred by study of where the fish comes from on the reef... lagoonal and open water species preferring quiet flow, herbivores like tangs from reef crests and surging areas like stronger flow, etc>
2.) My PH is 8.3 middle of the day but my dKH id 10.4 and my calcium is 360. 
<all quite fine... let the ALK fall a little if your like and you'll be able to bring that calcium up a little. Small matter though>
How do I push my PH up without sending the alkalinity through the roof. 
<ease up on buffer and use more Kalkwasser instead... that will raise pH and calcium levels>
I am using ESV two part solution for buffer and calcium.
<a fine product... my favorite brand of its kind>
Thanks again for the help. James
<with kind regards, Anthony>

Too much water circulation?
Hi everyone! How was your weekend?
<Too short!>
A few days ago, the pump that I was using to return the water from the sump to the main tank failed. So in that hurry, I took one of the power heads from the main tank to replace the one who failed. Obviously the power head doesn't "pump" enough water so I went to buy another. The only pump I could find (suitable to be inside of my house without the night noise) was a "Little Giant" 5-msp (sump pump (submergible) which can propel 1000 gph @10' head.
<Are you sure this is saltwater safe? My guess is no.>
My tank is only 50 gallons, so that pump can drive 20 times the volume of my tank. It is too much?
<No>
I made a kind of flute with 4 nozzles pointed to different directions in order to create turbulence. Right now I only have 3 fish (2 damsel, 1 yellow tang) some hermit crabs, 4 turban snails, 1 brittle star, 40 pounds of LR, and a few polyps. My intention is to create a good place with good water flow and light to keep a reef tank.
<Sounds like you are on the right track, but do double check that pump, though.>
Thanks for your response, Carlos
<You are welcome. -Steven Pro>

120 Gallon Tank Flow Rates
Greetings to the WWM staff,
I am setting up a 120 AGA that will be used as a reef tank and have just a few questions about the flow rates that the tank can handle. The tank measures 4 X 2 X 2 and has 2 overflows, one in each rear corner. The overflows appear to be drilled to accept a 1” drain and a ¾” return, respectively.
<Fairly standard>
I have a custom acrylic sump in the basement with a capacity of 90 gallons and will be pumping back up to the display. I will calculate the required head pressure and size the pump accordingly, but I lack some required data at this point and cannot arrive at a logical conclusion that is based on fact. I intend to fabricate some Durso standpipe devices so that the wife won’t complain about noise and such coming from the overflows.
<Good idea>
I also would like to run (2) ¾” Sea Swirl return devices so that I have a very nice and turbulent water flow in my display. Since the tank will be dedicated to SPS, I think they will appreciate the water movement.
<Agreed>
How do I calculate to total capacity, expressed in GPH, of the 2 Durso standpipes?
<I would look at Richard Durso's homepage. He may have the figures there. At the very least, information on how much water he runs through his overflows.>
They will be 1” of course
<Do double check your design. I believe Richard recommends using 1 1/4" or 1 1/2" PVC for the drain with a reducing fitting at the very end.>
and I can size the pump accordingly but I certainly don’t need a bunch of water on the floor in room where I will house my display.
Many thanks in advance for your replies. Jason
<Good luck to you. -Steven Pro>

Re: too much water circulation?
Thank you for your response. I followed your advice, so I contacted the
people from Little Giant, and they told me what you said "this pump is not intended to use in marine aquariums". So I return it and change it. Thanks.
<You are welcome.>
Just to give some practical things that I observed with my reduced flow. Maybe 2-3 days after the flow was reduced, the hair algae started to grow over some parts of the rock, then Cyanobacteria appeared in spots over the sand, the skimmer started to produce just green tea substance instead the coffee product. It is amazing how fast the environment can be corrupted when just one (and so important as the water movement) condition is out of the right performance.
<Appropriate flow is a critical component.>
Today at night my tank will receive the benefit of a new pump 850 gal/h @3' ahead (my tank 50 gal.)
<Sounds good>
Greetings
<Have a nice day. -Steven Pro>

Water movement in clam tank
Hello everyone at WWM,
<Howdy>
I am planning an 85 gal. flatback hex tank (48 x 18 x 24), and the critical species that will inhabit the tank are Tridacnid clams. Can you help clarify my confusion over the flow rate for the tank?
<I'll try>
Daniel Knop's book on giant clams states that "we have to do with much less performance when keeping clams. .
. that is, five times the aquarium volume. . . seems reasonable to me." (pg. 147)
That seems pretty low.
<Mmm, it's okay... given "complete" movement of the water (little "dead areas")>
I am trying to keep the specs of the tank as close to standard as possible to keep the costs down. The tank can be constructed with up to four 1" drains and four or six 3/4" returns connected to 3/4" centipede return fittings for directional control. With this setup, the flow rate should max out at 1200 GPH--yes?
<Okay... bear in mind this is "real" flow rate versus an estimated value. In actual practice almost no pump installations yield near rated flow rates per interval>
Now the $6,400 question(s): Is this flow rate appropriate for a clam tank? Too much? Too little?
<About right. Most Tridacnid species, individuals will put up with, even enjoy greater water movement... as long as it's not directly blasting on them continuously>
Any wisdom you can offer would be greatly appreciated.
Your Web site has been a valuable resource for me in properly planning this tank. Thank you all!
<Glad to hear this. Bob Fenner>
Jeff

Circulation Situation
Greetings
<Scott F. tonight>
Sorry to ask so many questions but I am therefore I ask.
<I am here- therefore I answer!>
I have a Supreme Mag drive 950 in my 55 gallon sump which is in the basement as my return to the main tank which is a 75 gallon it travels vertically 6 feet the return line that is. I have checked the flow from the overflow back to the sump as 690 gph. I used a 5 gallon bucket to test I got one gallon per just under five seconds. first question is . Is this sufficient? second I was thinking about building a somewhat closed loop around the tank with tees in all four corners with flexible ball joints to point flow where it is needed will the mag drive 950 still be ok or should I put a dedicated pump for my closed loop.
<I like the idea of a dedicated pump for a closed loop. See Anthony's Book of Coral Propagation for some nice info. on circulation.>
I of course would prefer to utilize the 950. By the way I am in the terrible diatom phase with my tank (brown patches on everything) rock, glass, powerheads. hope it doesn't last long :(
<This, too, shall pass. Maintain good water quality, stay on top of changes, feed carefully, test...you'll be fine!>
Thanks for everything, keep up the great service you provide to all us green horns. John S.
<Thanks John, I learn more every day thanks to fine folks like you!>

Water Turnover Question
Hello again! 
<Hi there! Scott F. with you tonight>
I've been reading through your pages and pages and pages of FAQs and I must say its very impressive, I especially like the stocking recommendations, fewer fish then most people want but I agree 100%! On to the point. My tank is a 125 Gallon, with about 20 gallons of sump I would guess. I am using a RIO 2500, hooked to a spray bar. How much do I want to turn over the tank for fish only? The return is coming through a spray bar I made myself, could this be limiting how much return the pump gives me as well? Do I need more flow??? How much should I be turning over a fish only tank? Most info I find is for reefs.
<Not sure of the output of the Rio- but I like to shoot for 10 turns an hour, even for FOWLR>
Also, I am planning to upgrade my SeaLife 75 skimmer to a AquaC 180. Is it easy to inject ozone into this AquaC skimmer? It has no venturi and no air stone, I want to be sure it will work before I spend the $350 on it! It was a huge headache and hassle making the ozone work with the SeaLife skimmer, I would rather avoid that in the future, I would of course buy the carbon outlet collection cup for the AquaC, just curious how you get the ozone INTO it!
<Do contact Jason Kim at Aqua C. He is a great guy, and will be glad to talk you through the process. They have a great web site, too, which may provide some help>
Also I asked about my Redox last time I wrote you guys, and you said let it be and let it do its thing. Its been 2 weeks now, and my Redox is now up to 148 (from 135), in the last 3 days it seems to be going up about 2-3 a day.
Is this normal? Does it really take this long to raise? 
<A rising Redox is always good. How slow or fast depends upon the conditions within the tank>
I have also, since then removed all my sponges and filter pads from the tank, thinking they were leaching mass amounts of nitrates into the tank. The prefilter in the overflow box had never (in 2 years) been replaced, I just kept rinsing it. I really can't figure out why my water quality isn't that good. I just purchased a Nitrate test kit, so I will test when I get home, I suspect they will be high.
<Good move removing the pads. Do test the nitrate regularly>
Oh yah, Ammonia is .2 (I think because the tank sat empty for a week then I added a fish a week ago at least I hope that's why) Nitrite is 0, pH is 8.4, salinity is 1.024, and the temp. sits steady at about 81.7 (though it was down to 80.6 this morning so I just bought another heater, 1 200watt isn't enough for this tank).
<Ammonia is a sign that something is amiss! And you probably should shoot for around 500 total watts of heaters>
Attached are some pictures of the setup, any info you can give to help me provide a healthier living space for my poor puffer and future residence would be great. I plan to add 2 or 3 more fish to the porcupine puffer, some type of large angel (juvenile though), maybe a wrasse, and something else nice but not to huge. Below is a list of what the pictures are of.
Which reminds me! Last thing :) I've had the puffer for 2 weeks almost, and he never comes out when the lights are on. All day and evening when the tank lights are on, he sits under a rock and hardly moves (sleeping), then as soon as the lights go off, out he comes...even at night he's not real active, he pretty much just paces up an down in the corner of the tank, but he does eat (krill with Kent garlic Xtreme added to it) at night when he is out! Any idea what's up with this? He twitches and spins sometimes too, but not a lot.
<Well, the ammonia reading might have something to do with it...>
125gal_salt = tank as a whole
Overflow = Overflow box in the tank, not sure on its GPH, its an older AMiracle overflow.
Spraybar_return = my spray bar with a RIO 2500 on the other end, I believe its 1/2" PVC with small holes drilled in it, not 100% sure on size of the PVC though.
Sump1 = my main sump w/ bioballs and heater in it. Later added a 2nd sump
to hold more water and spread things out (AquaC will go here later I think) Sump2 = My addition sump, and Ozonator (useless pic other then shows the skimmers to small)
Collection Cup = My homemade collection cup, holds carbon to filter ozone from the air (1 hour at home depot and $5)
Sump2_Inside = Useful picture, shows my skimmer, RIO 2500 return (has an elbow on the end for when the water level gets low), Also homemade carbon filter for ozone skimmer water return, and a sponge that does nothing, its only 1/4 under water, I may just take it out tonight it may be a nitrate bed?? <probably, if not cleaned>
Sump1_Inside = Heater, a Minijet powerhead just moving water so it doesn't stagnate on the surface like it was, my ORP Redox meter hangs over the overflow drain tube.
Overflow2 and Overflow3 = My older style AMiracle overflow box from the outside, with sponge removed. Any idea how many GPH this does? Will I need a new one if I upgrade to a bigger return pump? or a second one?
<Check with the manufacturer to see how much flow it can handle, and modify as needed>
Thanks in advance for your help! You guys are great!!
<And have fun! Good Luck!>
Mark

Circulation
Hi, again. I have a 75 gallon reef tank, with a Yellow Tang and a few other fish. For circulation I have 2 Rio 2100's (I know, but I've had them for a while)
<I know they have a bad rap, but I also know of quite a few people that have them and have never had a problem. I would not recommend someone go out and buy them, but I would not tell you to throw them away either.>
on one side, at the top and bottom of the tank and shooting sideways, and a Rio 2100 on the other, also shooting sideways. In the middle, at the top and back of the tank, I have a 300 gph powerhead shooting out towards the front.
<Ballpark of a little under 2400 gph total.>
Flow seems good for the corals (they seem happy), but the fish seem to swim upstream quite a bit. I don't think they're struggling, but I'm wondering if I should lower the flow, or change it somehow.
<I would leave it alone. I don't think it is anywhere as powerful as the ocean.>
I don't want to have to replace the pumps I already have if I don't have to, and I don't know if I should lower the flow, since the corals seem quite satisfied. Is it too much, or do I just need to distribute it better, or...? Thanks for the incredible help you provide reef enthusiasts. :) Arthur
<You are welcome. -Steven Pro>

Re: Flow/Circulation
Recap - 75 gallon tall reef tank, 2 Rio 2100's pushing water from one side, 1 Rio 2100 pushing from the other, 300 gph powerhead pushing from middle back of tank forward. Corals like it, but the fish seem perturbed. I didn't think that I have too much flow (and based on your response to my last e-mail, neither do you),
<Correct>
but the fish (a powder blue tang and a clown fish) spend much of the day "leaning" into the current, looking like they're swimming upstream. They seem to seek out the pockets of the tank where current is strong.
<If they seek out these places, why would you think they do not like it? There are obviously some low flow areas they could escape to if they wished.>
The clownfish especially looks overwhelmed, I guess because he's so small. They look uncomfortable. Is this an issue, or can I relax and let them be? Arthur
<Please relax. This is nothing for them. -Steven Pro>

Circulation, aeration, tank top, cc stars...
>Thank you so much, but how do I size the additional powerheads?
><A couple of hundred GPH will be fine. Do arrange for the intakes to have a "pin-ball" piece of wet-dry media in their intakes to prevent animals being sucked in... and place these pumps in a fashion, where
>they can be easily removed for service, cleaning. Bob Fenner>
Okay, Bob, more questions. I ordered 2 powerheads that arrived tonight and I finally sat down and read your book and Michael Paletta's book.
Loved them both, and I finally feel more capable of asking some more "right" questions.
<Hmm, okay>
1. I got a Hagen 201 and a Powersweep 214. Aren't the strainers that are installed on them enough to keep critters out? I can't for the life of me even figure out where I would insert a bioball into these, since the strainers both protrude.
<Yes, these are good powerheads... that come with their own sufficient strainers... the above note is to emphasize the importance of having same... not to remove, leave off...>
2. I have always been concerned with the aeration of my water. Will the Caulerpa in my refugium/sump be adding enough O2 back in to mitigate my concerns? 
<It will indeed help... especially if constantly illuminated, or alternatively the sump is lit during "lights off" on your main/display tank>
I redirected my sump return about a year ago so that thetank surface is getting a little rippled from it. Is that all enough, or should I utilize the venturi air intake on the Hagen powerhead?
Would the resulting bubbles be a problem for my current or future petfish and invertebrates?
<You can test for dissolved oxygen with kits, meters... but would just observe livestock here... all likely fine>
3. When I upgraded my lighting to a SmartLite, I removed my tank top and the lens on the light to allow the greatest light transmittance.
This leaves some large gaps between the light and the tank rim where things might escape. After reading your book, I am concerned that might happen to me in the future. I am also worried about water splashing on the bulbs. I don't have a hood and the SmartLite canopy (do I havethose backwards?) is resting on the center tank support. It has beenthis way for about a year and everything has gone well (except for increased evaporation loss). Should I stop this foolhardiness and put the top back on my tank? I don't have any corals yet.
<I would leave all as is... and not worry>
4. I have a very large and a very puny chocolate chip starfish. They used to be the same size and one shrank and the other grew exponentially. This monster is now about 5 inches wide. I only have some damsels now as far as fish are concerned, but I am trying to plan my future stocking plan. I'm pretty sure I will have to remove the damsels because they have been allowed to rule the roost for too long and are very large and probably pretty aggressive. Will the starfish have to go back to the store too? My children and their friends love the starfish.
<I would leave them be as well.>
5. I successfully battled off a terrible turf algae invasion a couple of years ago, mostly by introducing a small cleanup crew to the tank.
The live rock is not very interesting now, except for a couple of fan worms and some other wormy looking stuff and I do have coralline algae, although it does not cover the rock yet. I am going to get more on top of things like calcium. I don't supplement and so the tank is only replenished by small frequent water changes. Should I add some new pieces of live rock for interest sake or leave well enough alone? I guess the starfish is probably eating a lot off of the rock too...
<Would likely add a bit more live rock... new livestock you plan on will change many dynamics, reveal other life going forward.>
I am getting more responsible and conscientious every day. Even if my tank takes forever to get to where I want it, my next trip to the local Monterey Bay Aquarium will be great now that I feel more informed.
<Ahh, the pleasure my friend>
Thanks so much.
Linda Swenberg
<Be chatting, sharing. Bob Fenner>

Return pump and powerheads
Hello again!
I have finally started to acquire the equipment to set up a FOWLR aquarium where I also want to add some soft corals and polyps over time. I thank you for your previous help and I have a few more questions.
I now have a 75gal reef-ready tank with an Oceanic PowerCompact light (110W, w. Coralife white and actinic blue bulbs). I intend to put a 20 gal sump underneath it, probably an Oceanic Sump model 1 (it will be difficult to put something bigger because of the doors/supports of the cabinet: Oceanic cherry oak cabinet). I realize I may need more light for the corals but that will have to wait for now. I do intend to buy around 90 lbs of live rock after I get the skimmer and sump.
Here are my questions:
1.) I will get an AquaC EV120 filter with a Mag-Drive 5 pump. I could get a Dolphin DP-560 pump for the same price. Do you favor one over the other? I have only seen the Mag Drive pumps locally.
<Both are fine.>
2.) My second inquiry has to do with the return pump. I believe I need about 750 gph through the sump plus some additional powerheads in the tank to turn the water over as much as possible. At the same time I want to balance the water flow to the sump to not make the system too noisy. I am planning to set up a Durso style standpipe (see http://www.rl180reef.com/pages/standpipe/standpipe_frame.htm for a description or http://home.att.net/~rstockman/overflow.htm for a more compact modification) that my LFS says really reduces the gurgling noise from the water falling down into the RR overflow box (if you know of other good methods, please let me know).
<This one is about ideal>
However, I have heard that if you get too big a return pump, noise will still be a problem. Is a Mag-Drive 9.5 too much?
<Yes... by about twice the flow-rate... Depending on what you want to achieve in this sump arrangement (definitely not a refugium at this turnover rate), a good five, six volumes of the main system per hour is fine>
The pump will be in the sump under the tank and will have to push an almost 5 ft. water column. I saw a chart at marinedepot.com that says the Mag-Drive 9.5 will push 750 gph with a 5 ft column. Others have recommended to just use a Mag-Drive 5 or 7 (250 or 420 gph at 5 ft). What would you recommend?
<!, the same>
Less flow through the sump but more in powerheads? More flow through the sump?
<The former>
3.) I am planning to use a few powerheads in the tank. Maxi Jets seem fairly inexpensive at marinedepot.com. Is it better to put in say 4 MaxiJet 400 @ 106 gph ea, or 2 (or even 4) MaxiJet 1200 @ 295 gph ea? 
<Four smaller>
I am concerned about too much flow from a single nozzle. Is this a problem?
<Yes, can be... animals, non-life getting sucked-up, blown about>
I don't have a good gut feeling yet for what these flow rates mean in terms of turbulence in the tank.
<You will>
Thanks for your help. I trust your judgment more than most of my LFSs.
<Trust only your own ultimately. We are all humans. Bob Fenner>

Lots of Questions - Jason breaks down
A) I have a MTC Pro 6500S Skimmer - it is about 2 feet high.
It is powered by a Rena 400.
Is this powerful enough. <<I should hope so. Two feet is quite the reaction chamber.>>
Is there some sort of conversion chart to figure this stuff out, or do we just have to ask the experts - like you. <<no conversion chart too many variables, mostly as all skimmers are not created equal.>>
I am a little confused on this - do people use powerheads to power their Skimmers??? <<some people do - certainly one of my three skimmers has a powerhead running it.>>
Can you recommend 1 for me??? <<that skimmer is running with a Rio 800. Some people like maxi-jets. You could ask this question on the WetWebDiscussion Forum where you could get easily 10 opinions on this: http://talk.wetwebfotos.com/ >>
B) When I read that you should have 10x (is this correct for an avg reef tank) the turn over of your tank size per hour. <<It's a good number to shoot for, yes but not worth killing yourself to accomplish>>
1) Do they mean 72 gallons - 20 gallons LR - LS = 50 gallons??? <<no, it means 72g + ?g in the sump = X total system gallons.>>
2) Do you count your return pump from sump 600 gph plus the power heads you have in the tank itself 3x200 gph??? <<depends on who you ask. I would cast my vote behind total flow - powerheads + circulation pumps.>>
(I would have 1200 total.) <<are you sure you're getting 600gph at the head in the tank. Many pumps that have a rated output of X drop to X minus something as you raise the output away from the pump [head feet]. You may only be getting 400gph. But in any case - what does it look like in the tank?>>
C) I am having problems with gravity flow from my overflow box.
What causes the bubbles to be created when it is released from the tube into the water. The tube is about 1 in underwater and the tube is a 25/34 mm Eheim - I think from what I have read the hole is 1in on the overflow.
- I have read that the overflow can't handle the GPH from the pump. Mine is Rio 2500 it pumps the water 4 ft to top of tank. <<ahh yes, Rio 2500 pumps approximately 520 gph at 4' according to Rio.>> The tubes are the wrong size, or that there is a vortex that is created in all of these overflows. <<Much talk of an overflow that you didn't name - who makes the overflow?>>
I have take of the pre filter pad on the skimmer to try increase flow rate, Put a small tube down the line to increase flow rate and stop the vortex, I have added some foam pads, I have prayed. These don't seem to make a big difference. <<you've confused me - we're talking about skimmers now? In any case, not sure any of those things would have helped if things were designed to work to a certain limit that you are now exceeding (?) - very hard to tell. Perhaps some more detail on these pieces/parts.>>
The only thing that has worked is to lower the power output from the Rio - but I think that works b/c less flow equals less bubbles created b/c less water is flowing through the tubes. The neg is less filtration :(
<<are you strictly concerned about the gurgling noise from the overflow? If this is the case, do try to get used to it and let you tank enjoy the increased flow.>>
I have checked your site thoroughly and have not found any definite answer on these - sorry If I am asking questions you have already answered. What can I do stop this problem I don't want to 'kill' the bubbles after they are created I just don't want them created at all.
<<in the overflow process? almost impossible to avoid some, is mostly attributed to the design of the overflow, which... you didn't tell me who makes it so I'm really not sure which direction to point you in.>>
Thanks for making life a little easier for all of us :)
Brad
<<Well thank you. Cheers, J -- >>

Follow-up on Lots of Questions - Jason tries again
Thanks for the reply JC
<<No problem...>>
-A is regarding a skimmer.
I wanted to know if the Rena makes enough bubbles for the skimmer. <<I think so, yes.>>
Please tell me what aerator you recommend besides Rena and what strength it should be approx. <<Check with the manufacturer for your skimmer.>>
Can it be too strong??? - What would happen with too many bubbles in the skimmer??? <<Don't think it could be too strong.>>
-B is regarding powerheads - ah... <<did I answer that one well enough for you?>>
-C is regarding Overflow.
The overflow is the one that comes with the All-Glass Tank 72 bow front- I assume it is a All-glass. <<Ahh ok, the built-in overflow - I have one of these myself in my 75. >>
2 tubes in over flow - 1 return and 1 intake. The intake is about 16 inches tall - There is a solid white pipe that is 12in long then continuing a clear pipe with square holes all around it for the next 4in. <<yes - very familiar>> The water level is about a 1/2in above the white pipe.
<<<are you strictly concerned about the gurgling noise from the overflow>>>
I could care less about this. <<ok>>
I just want to get rid of the bubbles and use the overflow to its max. <<what bubbles? I'm not sure I understand where those are coming from...>>
I have told you the make of the overflow in hopes you can help me further and answer the questions you were unable to b/c you did not know the make <<right, well now you know I have the same overflow so I can probably answer quite a few questions about it.>>
D - New question Do you know of a powerhead that has a foot print of 4in x 5in that is as powerful as the Rio 2500. That is all the space I have in my sump and I don't have the means/know-how to cut acrylic.
<<Can't think of one... you should browse the web and some online fish stores and see what you can find.>>
Thanks again.
Brad
<<You are welcome. Cheers, J -- >>

Water turns
A brief question regarding water turnover in a 15-gallon young (7 weeks old) reef aquarium. I have a CPR skimmer (Rio 600 pump) and a Via Aqua pump. Between the two I figure I'm getting about 280 gallons/hour total flow. I added a P. Ocellaris to this (main tank) yesterday. Last night when I noticed he looked stressed and was hiding in the corner. I turned both pumps off and this morning he looks better. Are these pumps providing too much by way of water turnover in my tank? Would I be better off removing the Via Aqua-- or alternating between the two?
Thanks,
Greg
<This is a bunch of water movement for such a small system, but the Clownfish's behavior likely has little to do with it. Water movement, "changes" in the wild are often many times this factor. The hiding, hanging in a corner or bottom is mainly due to being moved, placed in new circumstances. You could practice alternating the pumps to see if this suits. Bob Fenner>

Question (Rate per what function?)
I just bought a 150 gallon tank and I want a fish only saltwater aquarium I just don't know how many gallons per hour I need for this to work. Please email me back.
Thanks for your time.
Chris
<What? GPH for? Please read here re marine water circulation: http://www.wetwebmedia.com/circmarfaqs.htm and the linked files beyond.
Bob Fenner>

Water flow
Hi Bob & everyone:
<cheers>
I have 2 questions about my 60 gallon reef tank. The first one is about water flow. I have a Fluval pump filter circulation of 225 gallons per hour. The Fluval is theoretically for a 100 gallon tank. I have one of those "bubbler" things that I plug in that looks like a waterfall.
<still not enough water flow for this tank by itself... 4 to 10X tank volume per hour please>
I have about 2and 1/2" inches substrate - broken coral, shells, etc. and it really gets dirty under there.
<because it is too course. Weekly siphoning is needed with this type of media>
I also have a CPR backpack which is very effective for 6 fish, crabs, live rock, etc., but I feel that the substrate should get more aerated. 
<agreed>
I stir it up every couple of days and worry that the dust that comes out of it will make my fish sick, if not now, later.
<not to worry about>
Should I make the switch to aragonite or could a use a powerhead or two to get water circulating through the substrate? 
<you need MUCH more water flow here please>
If I put a powerhead in there, how powerful should it be. 
<two pumps 300gph or bigger would be very nice for this marine tank>
I just bought one which circulates 40 gallons per hour and that just doesn't seem to be nearly enough . 
<agreed>
It is a Rio 50. I should add that my fish are small, so I don't want to blow them out of the tank, either.
<pump size does not do this... improper direction does. Place the 2 PH in opposition so they converge for random turbulent flow rather than sever linear/laminar flow>
I am down to 2 mithrax crabs now and am happy to know, thanks to you all, that they don't start eating fish until their bodies are 2" across. As ever, thanks for all your help!! Connie Cavan
<best regards, Anthony>

Bulkhead Drilling
Hello Steven,
Recently I bought a used 100 gallon acrylic tank and my intention is to make it FOWLR. Right now it has one corner over flow with a 1 inch bulkhead at the bottom of the tank. From what I've been reading (FAQ's from www.wetwebmedia.com), your suggestion was to increase water turning rate meaning drilling more bulkheads.
<Correct>
Would you please let me know what's the good turning rate for my tank and how many more bulkheads should I drill to accomplish that rate.
<This depends on what in particular you wish to keep, but somewhere in the neighborhood of 10-20 times the tank volume per hour. I would use at least three 1" bulkheads in a 100.>
Also the suggest location of bulkheads (important). BTW, I'm using
plenum so I prefer not to drill at bottom.
<I drill most of my holes near the top. You can see a very nice diagram excerpted out of Anthony Calfo's "Book of Coral Propagation" here http://www.wetwebmedia.com/plumbingmarart.htm>
As always, thank you very much for your help and advise.
Regards, Dung Ngo
<You are welcome. -Steven Pro>

Re: Flow in a reef tank
Hi, I'm assuming the best way to do this would be to split the return with an adapter from the pump to opposite ends of the tank?
<or with a manifold that has 4-6 nozzles (adjustable or on a complete loop to even volume per nozzle)>
Does it make a difference if I split return close to the return pump or wait longer? 
<I'd wait for the tee or manifold tee at the top of the display>
And if I am using 3/4 inch return tubing for one line, should they both be split at 3/4 or two at 1/2 inch each? 
<requires some experimentation... all dependant on pump volume at head>
Thanks for all your help thus far--it has been great! Keep up the great job! Mike
<thanks kindly, Anthony>

Flow in a reef tank
Hi Again,
Should the current in a reef tank (75 gallon) be clockwise or counter-clockwise? Does it make a difference? Thanks, Mike
<neither are favorable... random turbulent flow or surge flow is best. Have opposing outlets converge upon each other for a nice random dynamic pattern (as in back left and back right discharge aimed to opposing front left and front left corners). For a 75 gallon reef tank you will need a minimum of 800 gph water flow... likely though that will not be enough for most species. Aim for 200o-3000gph for most tanks (more for sps corals and gorgonians). Best regards, Anthony>

Circulation
Is a 1200 gph external pump excessive for a 75 g tank with 50 lbs of live rock? I wanted to point two pvc outputs at each end of the tank towards each other to create ocean-like turbulence ( I am thinking of the last time I swam in the ocean myself. My setup now is with Rios 200 x 3 and this must be puny compared to a real reef). Also, I don't want the intrusion and heat from more powerful Rios. I have experienced a few coral deaths in the past from rapid infections (I assume they are bacteria because the previously healthy specimens disintegrate and dissolve within 24-36 hours). Any suggestions for a good pump. Thanks in advance.
>>
Rarely is circulation "too much"... and I agree with your philosophy... from direct experience. At 1200 gph you could have a good submersible (my fave choice is an Eheim), or a good external magnetic drive (am still a big fan of the Little Giant MD-SC series here... Iwakis produce too much heat...) Bob Fenner

Re: Filter Flow Rate Rules of Thumb...
Bob, thank you for your opinion on the number of fish I already have in my tank. I have taken heed!!! Therefore, I shall resist any more until the proper time.
<Ahh, this is best>
You also advised me on the type of canister filter that was a good one. Actually, I had been looking at the Eheim filter Model 2026 (which can be seen at www.petwarehouse.com), and this filter claims to have a flow rate of 250 gph. My question: is there a rule of thumb which, based on the size of your aquarium, would dictate the minimum flow rate of a filter?? 
<Hmm, "the more the merrier"... a few times the tank volume per hour (3,4-10 depending on the types of livestock, arrangement of plumbing...>
Do you think that this particular filter would be suitable for my reef tank??
<Yes, a very fine product>
Also, I have been watching for your books at the bookstore. Has the newest one been released yet??
<The Fishwatcher's Guide... is available through a few places... including through our site: www.WetWebMedia.com... check under/over the links to "Books for Sale".>
Thank you for your valued time & knowledge!!!
Pat Marren
<Glad to be help. Bob Fenner>

Circulation 
Hey Bob,
I just started cycling my tank three days ago (60 gallon tank, 80lbs. live sand, 90 lbs. live rock - pre-cured). Two questions: 1.) My tank absolutely reeks! I think it must be the rise in ammonia, though the smell makes me think something else might be amiss. Do I need to do a big water change? 
<Very likely yes... I would... do you have test kits... for pH, alkalinity, calcium levels? Do change the water in any case... and add some activated carbon in your filter flow path>
Will this go away by itself anytime soon? 
<Not soon enough...>
2.) I'm confused about how much aeration I need in the tank -- I have decent circulation (app. 550 gallons per hour circulated).
Does the water surface need to be agitated?
<Yes... a dissolved oxygen test... or Redox would aid you here>
Should I have the powerheads release air bubbles as well?
<Not necessarily... but the surface should be disrupted.>
Aesthetically, I wouldn't prefer it. A necessity, though?
<Well put... Please read through the "Circulation" section of the Marine Index on the www.WetWebMedia.com site for more here. Bob Fenner>
Many thanks!
Javier

Pump question
Hi Bob (or Lorenzo),<Bob currently>
Here I am almost ready to put my whole system together, then put live rock in and get it going. Here is the set up:
55gal tank ---> overflow box ---> 3ft. tall 4.5in diameter protein skimmer
(in sump - 35gal total, but only about 20gals of water in the sump) --->
through baffles ----> refugium ----> more baffles ----> pump? ----> back into 55gal tank.
My question is,....how do I know what size pump to get? Doesn't it have to equal (or close to equal) the amount of gallons per hour the overflow box is sucking out of the tank? If so, then how do I measure this amount? with a gallon jug and a stop watch?
<A possibility. Please see the "Pumps, pumping" section on the Pond Index part of the www.WetWebMedia.com site here>
Please help me help my tank not to spit up all over my floor.
Thanks,
Jana
p.s. Good idea: I was thinking,.... since we aquarist are forbidden to use soap or soap like products on our equipment, wouldn't baking soda be a good thing to use to scrub out hard stains?
<Yes, as long as you're careful not to scratch soft materials>
My mom always taught me to use baking soda on hard to remove 'gunk' on dishes and pans, and Bob Fenner always taught me to add a few teaspoons of baking soda a week on my tank to keep pH levels above 8.0. So wouldn't using baking soda to clean your equipment be a good idea, considering most of the baking soda is washed off with warm water after scrubbing?
<Yes>
Just an idea, please pass it on to others if you like it would be alright to do this.
Later,
Jana
<Be chatting my friend. Bob Fenner>

Re: pump question
Bob,
Do you mean my system needs to turn over 10 times my tanks volume per HOUR?
<Yes... about this rate>
Whew! That's' a lot! Also with a 55 gal main tank and a 35 gal sump with
about 20 gals of water actually in it, this is a total of 75 gals? 
<Actually, the calculated rate is ten times the system volume. That is, about 550 gph>
(I do include my sump tank amount when figuring out total volume, Hu?)
I read over the articles on the pond section.
I feel like my brain is frying.
<We ought to start a club>
I thought I was almost finished.
Wrong!
I am off to search some more for more clarity.
Jana
<Ah, tis pleasurable. The water movement in most parts of the seas is much greater... by far. Bob Fenner>

Re: Pump and refugium and circulation in general question
Thanks, a few more quickie questions though, (still about refugiums). When I explained to you that my refugium set up will have more then 1 sump, you said the other one could be used for live rock, and sand bed. You also mentioned this to someone named Rick in the FAQs who is setting up a 807 gallon reef tank( I could only DREAM of something like that!!). Is this because you're assuming the refugium will be housing some type of fish, or such, because mine will only be for macroalgae, and I assumed the LR, sandbed, crabs, and snails etc...., and the second strictly for total volume, or is there a reason I should put the LR, and such in the other sump away from the macroalgae. 
<The difference (in location, use of pumps) is almost certainly for limiting the flow rate through the refugium itself. Two, three or so actual volumes per hour is generally ideal for such sumps... and most folks "recirculation" is more than this... often much more>
If so, then what exactly goes together in which sump, and why, because I did not see any mention of separating these from one another. The only thing I saw which could relate is the mention of plenums, or barriers, which I thought was just to break up the flow a bit?
<Mmm, much to say here... the plenums serve several possible/real functions... the barriers as well... but not the same... Don't get me wrong, but you would do well to "read books"... not try to gain complete answers in these sorts of formats of learning...>
Also will everything not eventually get mixed together by the current going through the bulkheads?
<Hmm, yes, no... Bypass water from some parts of the same system will eventually be mixed... but not quickly if the "refugium" circulation is more limited... Bob Fenner>
Greg N
Montreal, Canada.
P.S. Can I use crushed coral in the refugium, ( I have lots left over from my tank setup) or does it have to be sand, or is the layering of the two with screens between better in this case?
<Crushed coral is fine.>

"Hey bob" (Water movement)
I have a quick question for you. I have a 40gallon reef tank, the inhabitants are 1, 4inch blue super crocea clam, 1-green-tipped frogspawn, and various xenia colonies. Here's the big question: I have a aqua-clear 402 powerhead on the left side of the tank giving current toward the opposite side of the tank, and I also have a little Rio powerhead 800,on the opposite side of the tank going towards the other powerhead current. My question: is this too much circulation for a 40, gallon reef tank? does it bother my corals? please help. 
<What you list shouldn't be too much water movement... but the only way to tell is by observing your livestock. Does your Xeniid colonies and frogspawn coral open up? You're likely fine here. Bob Fenner>