Overskimming: A Cause for Worry?

[NEReef]

So I am sure someone else has asked this but I would just like to here some recent opinions about whether overskimming is a real thing, and if it is should we even worry about it? In thinking through this issue I think there are a couple things we need to keep in our minds. Why do we skim is one of the most important probably followed closely by how does skimming actually work. First looking at why do we skim I think that is fairly obvious we are trying to keep our water as clean as possible. Without getting really into the science we're removing dissolved organics from the water via surface tension of the bubbles etc... that evolves into can we keep the water too clean to the detriment of our corals? (obviously dependent on what you are keeping sps lps softies etc) But lets talk in terms of a mixed reef setting where the majority of the coral would appreciate water that is clean but not sterile. Can you overskim in that case?? Skimmers have a theoretical threshold based on throughput and efficiency so would even an oversized skimmer really be able to overcome the physical limitations to be a detriment to your coral? Is it really just a matter of removing trace minerals?? In which case you could dose/ water change to maintain those levels? But i guess then it becomes a matter of is it worth all the trouble to dose/ water change vs just getting a smaller skimmer?? Let me know what you think/ any anecdotal evidence.

 

[mojo~]

The skimmer really cant overskim. Once the Doc s are removed it will shut down. the bigger the skimmer the sooner it will shut down. but it will also leave more in the water as the neck size will determine the level of docs left after it shuts down. To some extent. Too small of a skimmer and you will leave even more in the water. Its important to find one that is well balanced for your system.

 

[Alex T.]

^^^+1. You can't skim more than the tank has available. I never understood why people believed in overskimming.

 

[James77]

IME overskimming is not a problem at all, but oversized skimmers may set you up for less than optimal performance.

 

[NEReef]

Less then optimal performance as in you can't get it dialed in or you have to keep adjusting it? Cuz that would be annoying. I guess i just struggle with how to size because the manufacturers all have different claims and then you have to evaluate bioloads. I have never kept a high bioload tank because I have never had a decent Skimmer but with my new 350g tank I plan on keeping lots of fish so i want an absolutely solid Skimmer that will handle whatever I throw at it. Without spending tons of cash obviously lol.

 

[mavgi]

Personal I'm only run bigger skimmer on my system , I got 120 gallon and use monster skimmers all time. Skimmer never collect all detritus from the system and as much as water can flow through the skimmer it's better. Skimmer will skim on/ off but it's not mean that the system totaly clean. If you got 350 Gallon and plan to keep lots of fish better to keep good skimmer size that can handle lots of water feed or get two skimmer .

 

[mavgi]

From my experiance i dont think so specially when there is lots of fish on system and as far as my opinion for big system better to have two skimmer instead of one . those are my toys and the bigger one skim the best :

<a href="http://s44.photobucket.com/albums/f30/mavgi/?action=view&current=PIC_0109.jpg" target="_blank"><img src="http://i44.photobucket.com/albums/f30/mavgi/PIC_0109.jpg" border="0" alt="Photobucket"></a>

Today i got the new RLSS-10E and its also Rated for 396-660 gallons and im using it on my 120 gallon for 350 i was taking two...lol

<a href="http://s44.photobucket.com/albums/f30/mavgi/?action=view&current=IMG_20120605_182606.jpg" target="_blank"><img src="http://i44.photobucket.com/albums/f30/mavgi/IMG_20120605_182606.jpg" border="0" alt="Photobucket"></a>

Here it's start to break in :

 

[James77]

Less then optimal performance as in you can't get it dialed in or you have to keep adjusting it? Cuz that would be annoying. I guess i just struggle with how to size because the manufacturers all have different claims and then you have to evaluate bioloads. I have never kept a high bioload tank because I have never had a decent Skimmer but with my new 350g tank I plan on keeping lots of fish so i want an absolutely solid Skimmer that will handle whatever I throw at it. Without spending tons of cash obviously lol.

Ideally a skimmer would be producing a good amount of "head" and pushing it into the cup. When I have had way oversized skimmers, the most I get is crud buildup on the neck. That is less than optimal IMO and IME.

The 2 best performing skimmers I have had yet are an H&S a150, rated for a 225g, on a system that was about 200 gallons and a SRO 2000 rated for 180 gallons on a 140-ish gallon system.

I just went with an ATB elegance 200, it is rated for 100-300 gallons, it may be oversized. So far so good. But if you find an honest rating, I would base a choice on that. SRO saying up to 180g obviously means diefferent if it was high bioload, 120g may be more ideal. But it is far different than seaclones saying 150 gallons

 

[mavgi]

Ideally a skimmer would be producing a good amount of "head" and pushing it into the cup. When I have had way oversized skimmers, the most I get is crud buildup on the neck. That is less than optimal IMO and IME.

This is because most of the skimmer companies never do a real test on skimmer's neck size VS air flow.... And this why we see that some different skimmer size from same company perform better then other... without connection to the tank size. 350 gallon with lots of fish mean also lots of feeding and for keep this system healty it's better to have two good skimmer that can handle the system well.

 

[a.browning]

+1 to what others have said. Your skimmer can't skim out more organics than are in the water, so how could one overskim their aquarium? An extremely oversized skimmer may not perform as well 24/7, but it can't overskim your tank.

 

[brizhound]

I'm doing a build with a Reef Octopus xl8000 on a 225 gallon with a 98 gallon sump. If you can overskim then I definitely will do it. I didn't realize how BIG the skimmer was until I saw it in person.

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[TimeConsumer]

I'm doing a build with a Reef Octopus xl8000 on a 225 gallon with a 98 gallon sump. If you can overskim then I definitely will do it. I didn't realize how BIG the skimmer was until I saw it in person.

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:eek1:Yea, I think you may have overdone it just a smidge. How big is the neck on that monster, a foot?

That skimmer would work well on the 800g at my LFS. Hopefully it will do the same on your tank.

You could just go all-in and slap this puppy on it: http://coralvue.com/reef-ocopus-q8-commercial-protein-skimmer/ lol.

 

[brizhound]

:eek1:Yea, I think you may have overdone it just a smidge. How big is the neck on that monster, a foot?

That skimmer would work well on the 800g at my LFS. Hopefully it will do the same on your tank.

You could just go all-in and slap this puppy on it: http://coralvue.com/reef-ocopus-q8-commercial-protein-skimmer/ lol.

Yeah the neck is about 12inchs. We'll see how it works out. Thanks for the link I think I should get two of those and put them on my wifes RSM 130 lol. Now that's BIG!!

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[mojo~]

I'm doing a build with a Reef Octopus xl8000 on a 225 gallon with a 98 gallon sump. If you can overskim then I definitely will do it. I didn't realize how BIG the skimmer was until I saw it in person.

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thats way too large. the 3000 would be good on that tank . the 5000 is even a little on the large size.

I dont think people understand that with a skimmer too large for the system.. you actually skim less. it will build up in the neck and not collect in the cup. When you really understand how the skimmers work, how they remove organics and the balance of a skimmer. It will be like the water has parted and you can now see the way..

Really though, Too big is not better. Ratings are mostly bogus. You need to look at the water through put more than air intake really. And hardly anyone looks at the amount of water cycles through a a skimmer pump. You really have to know the pumps and how they do with water and air together.

For example .. Sedra 9000 pulls about 900 lph of air. Bubble blaster 2000 pulls about 1100 to 1200 lph of air. Does that mean the bb 2000 is a better for larger tanks....? The sedra 9000 pulls massive amounts of water and will cycle the water more often.

this is just one example.Its like saying a 454 in a chevette is faster in a race than 4cyl lotus elise. It has to be a balanced skimmer and it needs to match up to your system.

Mojo~

 

[Alex T.]

As long as the neck size is not too large for the system/bioload, a larger skimmer will just simply pull the organics out faster and then idle. IMHO this is not a bad thing but a good thing. If you do a search on Youtube, you'll find a video series from LA Fishguy where he meets and discusses protein skimmers with Euroreef (now ReefDynamics) owner Jeff Macare. Jeff is a wealth of knowledge in protein skimmers. If you can get past the LA Fishguy's (Jim Styme) comments and old-school beliefs in bio ball filtration, you'll learn many things you didn't know, and be able to make an informed decision.

I for one only ran a "system rated" skimmer once, and I'll never do it again. Oversized within reason is the way to go. Having that extra little bit of assurance should something die or the tank is overfed is good peace of mind.

 

[TimeConsumer]

Really though, Too big is not better. Ratings are mostly bogus. You need to look at the water through put more than air intake really. And hardly anyone looks at the amount of water cycles through a a skimmer pump. You really have to know the pumps and how they do with water and air together.

What sort of ratio should we look for when shopping for a skimmer for our tanks? How much water to air? How much flow to tank size? How big of a neck diameter to tank size?

 

[brizhound]

thats way too large. the 3000 would be good on that tank . the 5000 is even a little on the large size.

I dont think people understand that with a skimmer too large for the system.. you actually skim less. it will build up in the neck and not collect in the cup. When you really understand how the skimmers work, how they remove organics and the balance of a skimmer. It will be like the water has parted and you can now see the way..

Really though, Too big is not better. Ratings are mostly bogus. You need to look at the water through put more than air intake really. And hardly anyone looks at the amount of water cycles through a a skimmer pump. You really have to know the pumps and how they do with water and air together.

For example .. Sedra 9000 pulls about 900 lph of air. Bubble blaster 2000 pulls about 1100 to 1200 lph of air. Does that mean the bb 2000 is a better for larger tanks....? The sedra 9000 pulls massive amounts of water and will cycle the water more often.

this is just one example.Its like saying a 454 in a chevette is faster in a race than 4cyl lotus elise. It has to be a balanced skimmer and it needs to match up to your system.

Mojo~

Hey Mojo you make a good point. I've read alot about skimmers and realize that it's all about balance. As you know skimmer ratings don't mean a thing. When the skimmer came in I thought OMG isn't that a little overkill?! But I am having the system completely custom built so I am going by what the pro's suggest based on their experience and expertise. I'm not paying retail so it's not a way to get more $$ out if me. We are going to use the skimmer as a method of doing water changes as well by wet skimming once a month. It will be countered by dosing pumps and a ca reactor. We shall see....

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[gcarroll]

When I came up in this hobby, I was always taught to get a big skimmer. I still to this day recommned this to all that I advise. I think too much is emphisized on a skimmer pulling out skimmate consistantly. To me all that means is that you have just enough power to get by. I have never looked at pulling consistant skimmate as a benefit. That's like getting on the freeway with a car that is only capable of 65mph. Most would not feel safe if that were the case. Most would want some extra power just in case!

These are the benefits that I find in having what many call an oversized skimmer.

1. Highly aerated water breaks down organics quicker.
2. Highly aerated water improved O2 exchange.
3. If something dies it is nice to have that extra power on hand to remove it.
4. It's nice to have that extra power as it affords you the ability to feed heavily.

 

[NEReef]

thats way too large. the 3000 would be good on that tank . the 5000 is even a little on the large size.

I dont think people understand that with a skimmer too large for the system.. you actually skim less. it will build up in the neck and not collect in the cup. When you really understand how the skimmers work, how they remove organics and the balance of a skimmer. It will be like the water has parted and you can now see the way..

Really though, Too big is not better. Ratings are mostly bogus. You need to look at the water through put more than air intake really. And hardly anyone looks at the amount of water cycles through a a skimmer pump. You really have to know the pumps and how they do with water and air together.

For example .. Sedra 9000 pulls about 900 lph of air. Bubble blaster 2000 pulls about 1100 to 1200 lph of air. Does that mean the bb 2000 is a better for larger tanks....? The sedra 9000 pulls massive amounts of water and will cycle the water more often.

this is just one example.Its like saying a 454 in a chevette is faster in a race than 4cyl lotus elise. It has to be a balanced skimmer and it needs to match up to your system.

Mojo~

I guess that is one of my worries when i think about sizing right because at the tanks start up the bioload wont be very high so will i just get a gross neck and no actual removal into the cup? Is this just part of the whole set up process not really skimming until you need it ie having a bioload high enough to push the skimmer to reach good foam buildup?

 

[NEReef]

Another thing i was thinking about is if the skimmer is "cycling off" is that because the bioload isnt high enough to make it foam into the cup so its just building up in the neck ie not making the water any cleaner? In which case you really wouldnt want it to cycle off because that doesnt mean your water is clean it just means you water isnt dirty enough for your skimmer to be able to clean it.