Why do we assume a large return pump is needed?
- Thread starter Herbert T. Kornfeld
- Start date
bond007069
New member
How do i figure head on a CL?
with RC calculator.
Would have pump five feet from exit point in tank.
with RC calculator.
Would have pump five feet from exit point in tank.
Herbert T. Kornfeld
In Memoriam
There is no head on a closed loop...the water is being taken from the tank and pumped right back in. If anything the bends in the piping could be considered back-pressure...but spa-flex/hoses and mimimal elbows help keep this to the min. Or, many pumps work even better with a larger diameter pipe...esp a high flow/lower head pump like a T4...instead of 1" pipe, simply using 1-1/4 or 1-1/2" pipe can make for less restriction and help you get he most out of your pumps. I dont like running 1.5" PVC myself, so I split the output right after it exits the pump usually, or shortly after...into two 1" outlets instead. But actual head pressure...doesnt happen. Thats why closed loops are a better use for your flow pumps.
bond007069
New member
No head even if CL is sitting on the ground?
Why is that different than a return pump, i am sorry to be such a pain. LOL
Thanks
Why is that different than a return pump, i am sorry to be such a pain. LOL
Thanks
Herbert T. Kornfeld
In Memoriam
because the water pressure going in the pump due to depth is the same as the pressure on the outlet.
Nataku
Premium Member
Herbert T. Kornfeld said:
actually, there is head loss in CL. Friction from the tube wall, turbulence, elbow turns etc. but effects of these is mininal because of the short length of the flow in a CL.
On the subject at hand, I agree with Dr. Kornfeld. Low flow in the sump is the way to go. I am putting up a 90g AGA, will go with a Sequence Dart to power a ETSS pro skimmer and return. I figure about 500g/hr to the return and the rest to the skimmer.
bond007069
New member
Ok my experiement, no changes in anything, pH, skimmer the same output, temp about 1 degree lower, fish and corals look fine.
It was quieter, that is about all i noticed.
It was quieter, that is about all i noticed.
Herbert T. Kornfeld
In Memoriam
Nataku
Thats pretty much what I was getting at...with regards to head loss. There is some friction, elbows, etc...but by using long elbows, extra-large piping, and the like this BACK-PRESSURE is minimal and pales in comparison to "head-loss", which is loss due to gravity...and in the case of a closed loop, there is no head-loss...just back-pressure. Two different things...he asked about head-loss...not back-pressure.
As for you bond...you might notice over time that your skimmate changes in your skimmer...just as effective, if not more depending on how low and direct your flow can be from the tank's flow to the skimmer. Hey, isnt lowering your temp a good thing? And the noise...thats why I started doing the low flow thing...sick of having a toilet in my livingroom. But something you arent telling and wont notice yet is how much less electricity you are using...and more flow you can get from the high-flow pumps you do have by eliminating the head-pressure on them.
Thats pretty much what I was getting at...with regards to head loss. There is some friction, elbows, etc...but by using long elbows, extra-large piping, and the like this BACK-PRESSURE is minimal and pales in comparison to "head-loss", which is loss due to gravity...and in the case of a closed loop, there is no head-loss...just back-pressure. Two different things...he asked about head-loss...not back-pressure.
As for you bond...you might notice over time that your skimmate changes in your skimmer...just as effective, if not more depending on how low and direct your flow can be from the tank's flow to the skimmer. Hey, isnt lowering your temp a good thing? And the noise...thats why I started doing the low flow thing...sick of having a toilet in my livingroom. But something you arent telling and wont notice yet is how much less electricity you are using...and more flow you can get from the high-flow pumps you do have by eliminating the head-pressure on them.
fish_taste_good
Premium Member
Herbert,
I am flirting with this idea of yours and am pretty intrigued by it. The Eheim 1250 looks like a pretty decent pump for a return on a 90 to achieve a low flow setup. I like the price but how does it get primed?
My original idea was to keep any plumbing out of the display portion. I ended up making a spray bar that is powered by my LG as the return. This idea works pretty well, but your logic makes perfect sense to me and I would like to see how it functions as the LG is loud as heck.
In your opinion, will the Eheim 1250 be ok as an external return pump (no spray bar) and say one SEIO or Tunze in the opposite corner of the display? I also have a few JBJ dual output powerheads that I could use instead. I keep softies and would eventually like to try a few stonies like hammers or frogspawn.
Skimmer is a euro reef powered by a sedra 3500. I think its a 5-3. Will be placed in the sumps main return, and I am debating on making it external for that as well to help with heat. I live in FL.
Thanks,
I am flirting with this idea of yours and am pretty intrigued by it. The Eheim 1250 looks like a pretty decent pump for a return on a 90 to achieve a low flow setup. I like the price but how does it get primed?
My original idea was to keep any plumbing out of the display portion. I ended up making a spray bar that is powered by my LG as the return. This idea works pretty well, but your logic makes perfect sense to me and I would like to see how it functions as the LG is loud as heck.
In your opinion, will the Eheim 1250 be ok as an external return pump (no spray bar) and say one SEIO or Tunze in the opposite corner of the display? I also have a few JBJ dual output powerheads that I could use instead. I keep softies and would eventually like to try a few stonies like hammers or frogspawn.
Skimmer is a euro reef powered by a sedra 3500. I think its a 5-3. Will be placed in the sumps main return, and I am debating on making it external for that as well to help with heat. I live in FL.
Thanks,
spankerbob
New member
Hey herby, I have now spent abount an hour reading through this thread, very interesting btw, I see only one problem you keep stating look at my examples DNA and danano. DNA uses only 100gph overflow, it has to be that slow to feed his skimmer. He does not state what he uses for a return pump but he does use more than one stand pipe. He also keeps almost no fish, resulting in a low bioload. As for the second example, Danano is running an ehiem 1262 rated at 790gph with 4' head. That is not what you have kept repeating over and over, 100gph remember. I do agree with you that some of us are defeating the purpose of a refuge/sump with the high flow, but you do need to remember that every situation has different circumstances and the perameters therefore change. I am in no way saying you are wrong, because your not, but alot of people who post on these boards take everything to one extreme or the other with out actually thinking before they act or post. JMO
Herbert T. Kornfeld
In Memoriam
fish_taste_good
there is no priming involved with the eheim 1250 that I know of...its submerged in your sump. The rest of your plan sounds good.
spankerbob,
the sump throughput is only 100gph on DNA's. The second overflow is a backup should the first get clogged...as the primary is so finely tuned and could easily be clogged as it runs directly into the skimmer. There is an easier way to do this, but a diagram would make it easier...maybe later.
I will admit that danano's tank isnt the 'pinnacle' example of low flow like DNA's and so many others, but a long shot away from those who run returns on their 120's with 3000gph flow pumps. His overflow with the 1262 prolly runs about 500gph...nothing too high. I just wanted to give an example that wasnt as radical as DNA's.
DNA's tank does sport a large refugium as well...reminds me of those freshwater filtration principles where lowering the flow of a filter can be compensated for by raising the filtration medium...kinda like a Magnum 350 vs. an eheim classic (both rated for the same size tank but one has double the flow where the other has triple the media). But when you think about it, why would a reef work like that? It doesnt. If DNA keeps such a low bioload, how would having all that extra refugium space be a benefit. His bioload is arguable...with all those anemones contributing quite a bit...but still, I agree, its pretty low. The one thing to keep in mind is that many companies make skimmers that recirculate, only needing 1x the tank capacity in gph. So running a sump with a skimmer in this fashion would be no different...the sump's water is just going to get processed and cleaned that much more before going back to the tank. And the other thing is this...proteins buildup at the surface of the water naturally through oxidation...so having just enough flow to skim the surface on any tank is really all that a protein skimmer needs.
I have seen FOLR tanks overseas that use the same principals and are stocked heavily. I could have posted links here, but they are mostly in german and Japanese...so whats the point. There was one german reefer running a 500g tank with a 300gph sump return. His tank was heavily stocked...something like 10 large angelfish, 24 tangs, 36 wrasses...and his sump consisted of a 120g tank, a large H&S skimmer (3xeheim 1260 mixing pumps), and a small refugium. His tank was slowly turning into a reef, as things were just starting to get added over time with the LR and to have something on all the liverock...and so he was just starting to add large in tank powerherads, but otehrwise the tank was running fine off nothing but the 300gph overflow and nothing else in the tank!
there is no priming involved with the eheim 1250 that I know of...its submerged in your sump. The rest of your plan sounds good.
spankerbob,
the sump throughput is only 100gph on DNA's. The second overflow is a backup should the first get clogged...as the primary is so finely tuned and could easily be clogged as it runs directly into the skimmer. There is an easier way to do this, but a diagram would make it easier...maybe later.
I will admit that danano's tank isnt the 'pinnacle' example of low flow like DNA's and so many others, but a long shot away from those who run returns on their 120's with 3000gph flow pumps. His overflow with the 1262 prolly runs about 500gph...nothing too high. I just wanted to give an example that wasnt as radical as DNA's.
DNA's tank does sport a large refugium as well...reminds me of those freshwater filtration principles where lowering the flow of a filter can be compensated for by raising the filtration medium...kinda like a Magnum 350 vs. an eheim classic (both rated for the same size tank but one has double the flow where the other has triple the media). But when you think about it, why would a reef work like that? It doesnt. If DNA keeps such a low bioload, how would having all that extra refugium space be a benefit. His bioload is arguable...with all those anemones contributing quite a bit...but still, I agree, its pretty low. The one thing to keep in mind is that many companies make skimmers that recirculate, only needing 1x the tank capacity in gph. So running a sump with a skimmer in this fashion would be no different...the sump's water is just going to get processed and cleaned that much more before going back to the tank. And the other thing is this...proteins buildup at the surface of the water naturally through oxidation...so having just enough flow to skim the surface on any tank is really all that a protein skimmer needs.
I have seen FOLR tanks overseas that use the same principals and are stocked heavily. I could have posted links here, but they are mostly in german and Japanese...so whats the point. There was one german reefer running a 500g tank with a 300gph sump return. His tank was heavily stocked...something like 10 large angelfish, 24 tangs, 36 wrasses...and his sump consisted of a 120g tank, a large H&S skimmer (3xeheim 1260 mixing pumps), and a small refugium. His tank was slowly turning into a reef, as things were just starting to get added over time with the LR and to have something on all the liverock...and so he was just starting to add large in tank powerherads, but otehrwise the tank was running fine off nothing but the 300gph overflow and nothing else in the tank!
fish_taste_good
Premium Member
Must the eheim be run in the sump? I am looking to do it externally.
Thanks for the input. I am looking at the costs and it seems like it would pay for itself rather quickly.
Thanks for the input. I am looking at the costs and it seems like it would pay for itself rather quickly.
It can run external. I assume you will be using a "n" tube over the top of your sump unless it's drilled. You can prime either by hooking up the pump and suction line then filling from the top of the output side via a union, and the pump should be able to take over, or connect it all up, then slide a piece of airline hose up the input of the suction side, which is underwater of course, and sucking all the air out, then remove the hose. I use the later method on my closed loop pump, skimmer feed pump, and return pump. My sump is not drilled.fish_taste_good said:
fish_taste_good
Premium Member
I am going to give it a try I think. In case I dont like it, or my fish dont, I still have a pretty decent pump lying around.
Thanks for the info.
6 days without posts. wow
Thanks for the info.
6 days without posts. wow
Herbert T. Kornfeld
In Memoriam
Hey guys, could you help me out here...Bean Animal needs an education on closed loops and head pressures...I just cant get through to him...please stop by the following thread and tell him....TELL HIM!!!!
http://reefcentral.com/forums/showthread.php?s=&postid=5396909#post5396909
http://reefcentral.com/forums/showthread.php?s=&postid=5396909#post5396909
skippyreef
New member
Love the thinking this thread induced!
So here is my question:
Main tank is 270 gallons. Skimmer is a H&S A200 and I only need about 500GPH through it I believe.
In the tank there will be: Tunze Wave Box, 3 6080's, 2 6100's. I also have two penductors for the return lines. This is a BB SPS (reef flat biotope) that will house many tables and stags.
I am seeding my reef ceramic rock for two months prior to placement in the tank. This tank will be all reef ceramic rock including the back wall plates (all ordered from www.captiveoceans.com) to give a more natural appearace and places to atach corals on the walls.
Now using the penductors I have thought about teh new Iwakin RLT 100 Pressure rated pump. This will pump 1440 GPH at teh 23 head the weg page I bought them from says to figure in.
That will turn the tank over like 5 times and hour with the sump and frag tank figured in the volume. I think that the suspended detritus will make it into the skimmer nad the sump will be elevated in the fishroom so it is only a couple feet from the inlet/return lines.
So here is my question:
Main tank is 270 gallons. Skimmer is a H&S A200 and I only need about 500GPH through it I believe.
In the tank there will be: Tunze Wave Box, 3 6080's, 2 6100's. I also have two penductors for the return lines. This is a BB SPS (reef flat biotope) that will house many tables and stags.
I am seeding my reef ceramic rock for two months prior to placement in the tank. This tank will be all reef ceramic rock including the back wall plates (all ordered from www.captiveoceans.com) to give a more natural appearace and places to atach corals on the walls.
Now using the penductors I have thought about teh new Iwakin RLT 100 Pressure rated pump. This will pump 1440 GPH at teh 23 head the weg page I bought them from says to figure in.
That will turn the tank over like 5 times and hour with the sump and frag tank figured in the volume. I think that the suspended detritus will make it into the skimmer nad the sump will be elevated in the fishroom so it is only a couple feet from the inlet/return lines.
Herbert T. Kornfeld
In Memoriam
Wow, thats a good question mwood. What is too low...eh? I wouldnt know, the most extreme that I get to see is a 125g with only 150gph for the overflow. The main things I would think cound are that oils, proteins, and scum do not get a chance to build up anywhere on the surface. The second minimum would be the protein skimmer. If you use a recirculating skimmer, like a Euroreef RC, H&S, deltec, or recirc style beckett, they have the minimum flow through listed on the specs. This would also be the minimum for your sump return then too. Often this is 1-1.5x the tank volume per hour. On non recirculating skimmers, this figure is harder to achieve, but if you have an ER, ASM, etc...you could find the similar sized skimmer that you have in the non-recirc model and assume that the minimum sump flowthrough would be the flow spec of the equal RC model. IMO, the min should be 1x the tank's volume per hour...so a 150g should have at least 150gph overflow....or a 55g should have about 55gph overflow. DNA seems to have taken this even lower, at only 100gph for a 300+ gallon system...but he also has an huge refugium and low bio-load to compensate...showing that there are no exact rules. But 9 times out of 10, I would go with the minimum recirculating skimmer spec of 1x the tank volume per hour as the sump return rate.
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