recirculating vs regular skimmer

DaveG99 · 01/11/2009, 09:19 AM

I know the difference is the recirculating skimmer has a pump feeding it as well as a pump running the skimmer. But what is the advantage of one way or the other?

cashman95 · 01/11/2009, 09:54 AM

Recirculating allows for longer contact time in the skimmer, and more air introduced per gallon of water introduced. Plus you have more options with skimmer placement.(internal/external)

A regular skimmer doesnt need an extra pump to feed it, and tends to be less expensive.

hahnmeister · 01/11/2009, 10:15 AM

With some of the newer 'high efficiency' skimmers and how they work (ATI bubblemaster, RE bubbleking, CoralVue Extreme/Pro, ATB Cone, KZ, etc.... you get the picture) vs. more traditional designs, the recirculating option provides little to no performance advantage as far as 'extended contact time' goes.

cashman95 · 01/11/2009, 10:27 AM

Very true!

bimmerzs · 01/11/2009, 10:35 AM

One of the real "advantages" is that you do not need to maintain a steady water level in the skimmer area if you use a recirc skimmer in-sump. So if for some reason your sump level varies, this type of skimmer would perform better in this circumstance.

Cheers,

pjf · 01/11/2009, 10:57 AM

An advantage of a recirculating skimmer is that it can be "gravity fed" undiluted surface water directly from the overflow.

MSX-Rob · 01/11/2009, 01:03 PM

Quote:

Originally posted by hahnmeister
With some of the newer 'high efficiency' skimmers and how they work (ATI bubblemaster, RE bubbleking, CoralVue Extreme/Pro, ATB Cone, KZ, etc.... you get the picture) vs. more traditional designs, the recirculating option provides little to no performance advantage as far as 'extended contact time' goes.

I completely agree. There was a time when you could not inject enough air into the column, to compensate for this, you could recirc your skimmer. Like Hahn said above, I do not think it is as necessary anymore with the newer pumps and options out there.

GSMguy · 01/11/2009, 01:25 PM

milked is milked there comes a time when you need some space in the skimmer for water and adding more air wont help performance

hairyman1 · 01/12/2009, 03:04 PM

Yeah those new skimmer designs may be more efficient than cylinder recirculating designs, but that won't stop manufacturers from making recirc-cones in the near future and hyping them as improvements on the original design which I believe they will be. Control of the process flow provides an engineering advantage to any skimmer and gives it more flexibility/controlability like when trying to control some skimmers that are tempermental and overflow alot or not running a consistant sump level. I don't have these issues, but it seems many on RC do and recirc skimmers make the skimmer more predictable and easier to live with. You all just wait and see when the recirculating cones come out and the things they will hype/write about them. They might say something like 'there's something about this recirculating cone skimmer." Hmmm.

hahnmeister · 01/12/2009, 08:03 PM

I wouldnt say its 'hype'... some people simply want to run external rather than internal, and so recirc is what you have to do.

Recirc cones have been out for a while... I have one. They werent a high priority at first, but demand was high.

There are some mechanical advantages that you mention, some not exclusive to only recirc/external, but often that is the case. Having the mixing pump draw from the same body of water that its blowing back into eliminates any back pressure that would happen if you have the mixing pump drawing from say... a 8" sump water depth and pushing into a 24" tall water height. Recirc with more traditional designs (counter current) also means you can mount a larger pump on a smaller body and not have to worry about microbubbles flying out of the outlet because the throughput (say, 200-300gph) is less than the mixing pump's throughput (say, 900gph).

hairyman1 · 01/13/2009, 07:19 PM

Yeah your right, hype is probably not the best word. Hey so you have a recirc-cone. So does it have any advantages over a standard cone or is it mainly an option for those who want to run external?

shelburn61 · 01/14/2009, 12:41 PM

I'm running an internal cone skimmer, and I do kinda miss the set and forget simplicity of a recirc skimmer. It is certainly taking me longer to get this one dialed in...

This thread does a pretty good job of describing the pros and cons of each config. With newer pump/skimmer technology single-pass skimmers have caught up with recirc designs for skimming efficiency. However, based on your system/sump desing, one style may be a better fit.

orangekush4 · 01/14/2009, 02:14 PM

I have used allot of skimmers and I'll proly never buy a in sump.
What I like most about the RC skimmers, you have more control of the skimmer and it looks cleaner on a set up. It's very nice to drain the skimmer and pull it out of the stand for cleaning. My insump skimmer got salt creep no matter how clean I keepet them.IMO both skimme good.

Brian Prestwood · 10/21/2009, 09:17 AM

Hey Guys

I know this is an old thread but I've recently been considering some mods to my last skimmer design, a BK Mini-200 knock off with a recirc mod,...

and this subject has been on my mind. Specifically, I'm considering switching to single pass.

Allowing for the higher water:air ratios the newer foam pumps (Red Dragon, SICCE, etc) produce I see that, from the perspective of the foam pump only, recirc doesn't have an advantage over single pass.

However, I noticed in my testing that the higher the venturi head pressure at startup the lower the max air draw. In other words, if you start a skimmer empty the max air draw will be higher than if you start it full.

As I was filling my skimmer the air draw increased. It peaked at around 8". At around 15" it started to drop off. I realize the levels will vary by pump but the trend held across all the pumps I tested.

Do the recommended water levels for single pass skimmers take this into account?

01/11/2009, 09:19 AM	#1
DaveG99 Registered Member Join Date: Jan 2006 Location: Forney Texas Posts: 1,597	recirculating vs regular skimmer I know the difference is the recirculating skimmer has a pump feeding it as well as a pump running the skimmer. But what is the advantage of one way or the other?

01/11/2009, 09:54 AM	#2
cashman95 Registered Member Join Date: Nov 2006 Location: Greenville, S.C. Posts: 810	Recirculating allows for longer contact time in the skimmer, and more air introduced per gallon of water introduced. Plus you have more options with skimmer placement.(internal/external) A regular skimmer doesnt need an extra pump to feed it, and tends to be less expensive. __________________ SPS Tank with sump in the garage, 400watt Radium/Lumatek ballast,ReefKeeper2 controlling it all!! VHO actinics in the works! Current Tank Info: 24x24x20 Rimless Cube

01/11/2009, 10:27 AM	#4
cashman95 Registered Member Join Date: Nov 2006 Location: Greenville, S.C. Posts: 810	Very true! __________________ SPS Tank with sump in the garage, 400watt Radium/Lumatek ballast,ReefKeeper2 controlling it all!! VHO actinics in the works! Current Tank Info: 24x24x20 Rimless Cube

01/11/2009, 10:35 AM	#5
bimmerzs BadMotorScooter Join Date: Apr 2006 Location: Oregon Posts: 291	One of the real "advantages" is that you do not need to maintain a steady water level in the skimmer area if you use a recirc skimmer in-sump. So if for some reason your sump level varies, this type of skimmer would perform better in this circumstance. Cheers, __________________ Ron C Member DFWMAS, ARC and Reefcentral Current Tank Info: IM LAGOON 25G mixed reef

01/11/2009, 01:25 PM	#8
GSMguy Registered Member Join Date: Oct 2006 Location: Northern New Mexico Posts: 17,420	milked is milked there comes a time when you need some space in the skimmer for water and adding more air wont help performance __________________ Nick. Conehead. Shallow Reef club. Current Tank Info: 48"x27"x14" Envision Acrylic rimless, 6x39w ATi Sunpower, Custom ATB Deluxe Skimmer, 4x tunze nano stream,ATB flowstar 1500, ACJR, Tunze osmolator.

01/11/2009, 10:15 AM	#3
hahnmeister Moved On Join Date: Sep 2005 Location: Brew City, WI Posts: 10,156	With some of the newer 'high efficiency' skimmers and how they work (ATI bubblemaster, RE bubbleking, CoralVue Extreme/Pro, ATB Cone, KZ, etc.... you get the picture) vs. more traditional designs, the recirculating option provides little to no performance advantage as far as 'extended contact time' goes.

01/11/2009, 10:57 AM	#6
pjf Premium Member Join Date: May 2005 Location: Colorado Posts: 2,954	An advantage of a recirculating skimmer is that it can be "gravity fed" undiluted surface water directly from the overflow.

01/12/2009, 03:04 PM	#9
hairyman1 Registered Member Join Date: Oct 2007 Location: Illinois Posts: 271	Yeah those new skimmer designs may be more efficient than cylinder recirculating designs, but that won't stop manufacturers from making recirc-cones in the near future and hyping them as improvements on the original design which I believe they will be. Control of the process flow provides an engineering advantage to any skimmer and gives it more flexibility/controlability like when trying to control some skimmers that are tempermental and overflow alot or not running a consistant sump level. I don't have these issues, but it seems many on RC do and recirc skimmers make the skimmer more predictable and easier to live with. You all just wait and see when the recirculating cones come out and the things they will hype/write about them. They might say something like 'there's something about this recirculating cone skimmer." Hmmm.

01/12/2009, 08:03 PM	#10
hahnmeister Moved On Join Date: Sep 2005 Location: Brew City, WI Posts: 10,156	I wouldnt say its 'hype'... some people simply want to run external rather than internal, and so recirc is what you have to do. Recirc cones have been out for a while... I have one. They werent a high priority at first, but demand was high. There are some mechanical advantages that you mention, some not exclusive to only recirc/external, but often that is the case. Having the mixing pump draw from the same body of water that its blowing back into eliminates any back pressure that would happen if you have the mixing pump drawing from say... a 8" sump water depth and pushing into a 24" tall water height. Recirc with more traditional designs (counter current) also means you can mount a larger pump on a smaller body and not have to worry about microbubbles flying out of the outlet because the throughput (say, 200-300gph) is less than the mixing pump's throughput (say, 900gph).

01/13/2009, 07:19 PM	#11
hairyman1 Registered Member Join Date: Oct 2007 Location: Illinois Posts: 271	Yeah your right, hype is probably not the best word. Hey so you have a recirc-cone. So does it have any advantages over a standard cone or is it mainly an option for those who want to run external?

01/14/2009, 12:41 PM	#12
shelburn61 Registered Member Join Date: Oct 2004 Location: Charlotte Posts: 2,094	I'm running an internal cone skimmer, and I do kinda miss the set and forget simplicity of a recirc skimmer. It is certainly taking me longer to get this one dialed in... This thread does a pretty good job of describing the pros and cons of each config. With newer pump/skimmer technology single-pass skimmers have caught up with recirc designs for skimming efficiency. However, based on your system/sump desing, one style may be a better fit.

01/14/2009, 02:14 PM	#13
orangekush4 Registered Member Join Date: Feb 2005 Posts: 367	I have used allot of skimmers and I'll proly never buy a in sump. What I like most about the RC skimmers, you have more control of the skimmer and it looks cleaner on a set up. It's very nice to drain the skimmer and pull it out of the stand for cleaning. My insump skimmer got salt creep no matter how clean I keepet them.IMO both skimme good.

10/21/2009, 09:17 AM	#14
Brian Prestwood Premium Member Join Date: Nov 2003 Location: Sacramento, CA Posts: 3,783	Hey Guys I know this is an old thread but I've recently been considering some mods to my last skimmer design, a BK Mini-200 knock off with a recirc mod,... and this subject has been on my mind. Specifically, I'm considering switching to single pass. Allowing for the higher water:air ratios the newer foam pumps (Red Dragon, SICCE, etc) produce I see that, from the perspective of the foam pump only, recirc doesn't have an advantage over single pass. However, I noticed in my testing that the higher the venturi head pressure at startup the lower the max air draw. In other words, if you start a skimmer empty the max air draw will be higher than if you start it full. As I was filling my skimmer the air draw increased. It peaked at around 8". At around 15" it started to drop off. I realize the levels will vary by pump but the trend held across all the pumps I tested. Do the recommended water levels for single pass skimmers take this into account?