Skimmers, are they really necessary?

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stanlalee

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All I know is my biocube 14 has no skimmer and plenty of sps and it's been doing beyond good (as you might see when I post the one year mark before/after in 2 months).
I also have a 30g/10g sump/skimmered reef that doesn't do nearly as well this go around and is on the exact same (water/water change, food/feeding, dosing etc) schedule, exact same fish/livestock with the 30g having exactly double of the 14g (4 fish vs 2, 2 cleaner shrimp vs 1). Both test the same. Same wave maker (again in proportion 2 in the 30g/1in biocube). Both have proven lighting. the biocube 50w led from what it's done in the past 10 months and the 30g from what it did in the past... growing SPS like weeds with the exact same metal halides over the same tank when I gave the hobby a 7 year break (exact same new ballasts a year ago and new but same ushio bulbs which I've stock piled).
I can't pinpoint why the skimmerless lower volume one does better (don't think it's skimmer related at all and test #s give me NO insight) but as my first skimmerless reef attempt it definitely proves to me skimmers are optional not required.
 
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Ghost25

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All I know is my biocube 14 has no skimmer and plenty of sps and it's been doing beyond good (as you might see when I post the one year mark before/after in 2 months).
I also have a 30g/10g sump/skimmered reef that doesn't do nearly as well this go around and is on the exact same (water/water change, food/feeding, dosing etc) schedule, exact same fish/livestock with the 30g having exactly double of the 14g (4 fish vs 2, 2 cleaner shrimp vs 1). Both test the same. Same wave maker (again in proportion 2 in the 30g/1in biocube). Both have proven lighting. the biocube 50w led from what it's done in the past 10 months and the 30g from what it did in the past... growing SPS like weeds with the exact same metal halides over the same tank when I gave the hobby a 7 year break (exact same new ballasts a year ago and new but same ushio bulbs which I've stock piled).
I can't pinpoint why the skimmerless lower volume one does better (don't think it's skimmer related at all and test #s give me NO insight) but as my first skimmerless reef attempt it definitely proves to me skimmers are optional not required.
I mean given what you've said it seems like the skimmer really is the main difference. Since you've established a skimmer isn't required for a thriving reef, why not at least try removing it from your other tank and see what happens?
 

Randy Holmes-Farley

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So wait, what exactly is complete? Shouldn't one just need "adequate"? Don't tanks naturally produce co2 at night?

My 2 cents: skimmers are not necessary especially if fish load is light. (If you ask someone who sells skimmers - yeah they are very necessary)

No reasonable person can dispute the fact that skimmers aren't "necessary". A single tank that an aquarist is satisfied with is proof that a skimmer was not necessary in that case.

But there are several points of finer distinction that get glossed over, and are not opinions but simple facts.

1. "What exactly is not complete?" If your pH changes day to night, aeration is not complete. Simple fact. (well, ignoring the highly unlikely possibility that the pH is only tracking with changes in your home air CO2). Yes, reef tanks produce CO2 at night and consume it during the day. That's what causes the pH swing. And a completely aerated tank would equilibrate its CO2 with that home air and not show a ph swing. So often, reefers look at their turbulent reef tank water and simply claim aeration is complete. No evidence that it is, and clear evidence that it is not if they measure pH and see a change day to night. Very few people measure oxygen in the water. Is it equilibrated? Without a measurement, how would you know? You cannot look at a tank and know. In my tank without a skimmer, the pH ran too high. The skimmer was useful and desirable for aeration, if nothing else.

2. "Shouldn't one just need "adequate"? " Same comment on adequate vs complete, but also, if you are striving for an adequate reef tank, then adequate everything is, well, adequate. if you are striving for better than adequate, a higher level of requirement than "adequate" may be needed.

3. Anyone with a great reef tank who has no skimmer, certainly has the right to claim a skimmer isn't necessary. But unless they have tried a skimmer on that exact tank, they cannot really say whether the tank would be better in some way (or not) if it did have a skimmer. Again, if they are striving for whatever they currently have, then that's fine. But they cannot claim they are not useful without trying one.
 
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fryman

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No reasonable person can dispute the fact that skimmers aren't "necessary". A single tank that an aquarist is satisfied with is proof that a skimmer was not necessary in that case.

But there are several points of finer distinction that get glossed over, and are not opinions but simple facts.

1. "What exactly is not complete?" If your pH changes day to night, aeration is not complete. Simple fact. (well, ignoring the highly unlikely possibility that the pH is only tracking with changes in your home air CO2). Yes, reef tanks produce CO2 at night and consume it during the day. That's what causes the pH swing. And a completely aerated tank would equilibrate its CO2 with that home air and not show a ph swing. So often, reefers look at their turbulent reef tank water and simply claim aeration is complete. No evidence that it is, and clear evidence that it is not if they measure pH and see a change day to night. Very few people measure oxygen in the water. Is it equilibrated? Without a measurement, how would you know? You cannot look at a tank and know. In my tank without a skimmer, the pH ran too high. The skimmer was useful and desirable for aeration, if nothing else.

2. "Shouldn't one just need "adequate"? " Same comment on adequate vs complete, but also, if you are striving for an adequate reef tank, then adequate everything is, well, adequate. if you are striving for better than adequate, a higher level of requirement than "adequate" may be needed.

3. Anyone with a great reef tank who has no skimmer, certainly has the right to claim a skimmer isn't necessary. But unless they have tried a skimmer on that exact tank, they cannot really say whether the tank would be better in some way (or not) if it did have a skimmer. Again, if they are striving for whatever they currently have, then that's fine. But they cannot claim they are not useful without trying one.
You make good points Randy but all tanks have a ph swing. Even the ocean has a ph swing. I've never heard anyone suggest we need to attempt to get rid of it entirely before and I'm doubtful that would be worth the effort. I don't expect the usual ph swing everyone has somehow hurts our livestock.

A skimmer was not even designed or intended to be an aquarium aerator, it's just a side effect. There are other (cheaper) ways to achieve the same using air stones for example, even if that was the primary goal of this equipment.

I agree it's best to try both running & not running a skimmer to see how a particular tank reacts. Some people have tried running a particular tank with/without a skimmer and found improvements one way or another. It can be an expensive experiment.

I think if you are achieving nutrient balance in other ways it's not worth getting a skimmer. If you are just starting a tank then it's worth getting one, it just makes things easier.
 

Randy Holmes-Farley

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You make good points Randy but all tanks have a ph swing. Even the ocean has a ph swing. I've never heard anyone suggest we need to attempt to get rid of it entirely before and I'm doubtful that would be worth the effort. I don't expect the usual ph swing everyone has somehow hurts our livestock.

Exactly my point: aeration is not complete, and folks claiming it is are not correct.

You may not have heard of it, but some folks do strive for pH stability and control. pH control is not low hanging fruit for most reefers, but that does not mean it cannot be useful.

There are discussion threads on this topic for those interested in deep understand on what pH stability and lack thereof really means...

 
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Randy Holmes-Farley

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A skimmer was not even designed or intended to be an aquarium aerator, it's just a side effect. There are other (cheaper) ways to achieve the same using air stones for example, even if that was the primary goal of this equipment.

I don't think it is clear that airstones are as effective, and they often have the huge drawback of salt spray.

It is not obvious to me that there are other good ways to provide aeration to a reef tank that are better or cheaper than skimmers.

Could someone design one? Maybe.
 

fryman

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Exactly my point: aeration is not complete, and folks claiming it is are not correct.

You may not have heard of it, but some folks do strive for pH stability and control. pH control is not low hanging fruit for most reefers, but that does not mean it cannot be useful.

There are discussion threads on this topic for those interested in deep understand on what pH stability and lack thereof really means...

Ok, but my point is skimmed tanks also have a ph swing. I personally have not detected any difference in ph swing after turning off the skimmdr.
 

Randy Holmes-Farley

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Ok, but my point is skimmed tanks also have a ph swing. I personally have not detected any difference in ph swing after turning off the skimmdr.

OK, but I clearly noticed a pH effect that was due to the ability of the tank to pull in CO2 when using my skimmer vs not.
 

JohnMzreef

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2. "Shouldn't one just need "adequate"? " Same comment on adequate vs complete, but also, if you are striving for an adequate reef tank, then adequate everything is, well, adequate. if you are striving for better than adequate, a higher level of requirement than "adequate" may be needed.
Seems we could debate the definition of "adequate" but lets not. My point was just that I am questioning whether "complete" equivalence of CO2 between air and water is really necessary (maybe it is? - convince me)

So, if you've ever had the experience of turning off your skimmer and then seen your tank go from struggling to thriving (maybe you haven't, but I have) and drawn the conclusion "this thing is sucking the life out of my tank" then its fair to say that a skimmer could be a "negative" instead of a "positive".

Now this is not necessarily an indictment of skimming. It could just be that in the past 30 years skimming (and filtration in general) has become way more effective and even outpaced our expectations. And maybe this inertia in expectations has be influenced by interested parties (sellers of these things). And that is not even an indictment of the sellers because hey at least they are competing with each other and improving the technology and we can't really expect them not to pitch their products.
 
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So, if you've ever had the experience of turning off your skimmer and then seen your tank go from struggling to thriving (maybe you haven't, but I have) and drawn the conclusion "this thing is sucking the life out of my tank" then its fair to say that a skimmer could be a "negative" instead of a "positive"...
It is interesting that some think that skimmers don't work well enough to merit their use, while others think they work so well that they compete with organisms for food.

I think they do a great job doing what they are intended to do... remove hydrophilic dissolved organics and the nutrients bound in them. I'll stipulate that removing those dissolved organics may produce negative effects in some cases. It is really dependent on the organisms in the system. If you have a ton of corals, sponges, clams, thriving algae/macroalgae, diverse planktonic life, and etc., a skimmer might not be for you. It might very well be competing for compounds that some of organisms need to flourish. If you have a less established system full of messy fish, a skimmer is likely a great option. There is a line somewhere between those two examples where reducing or eliminating skimming is not a bad idea.

I don't buy the aeration thing as a reason to run a skimmer. While I think they can help in that area, I would not run a skimmer just for that reason. If I didn't need help limiting dissolved organic compounds & nutrients, I would use the space occupied by a skimmer for something else. That said, I can't imagine my skimmer will be going away anytime soon.
 

CanuckReefer

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It is interesting that some think that skimmers don't work well enough to merit their use, while others think they work so well that they compete with organisms for food.

I think they do a great job doing what they are intended to do... remove hydrophilic dissolved organics and the nutrients bound in them. I'll stipulate that removing those dissolved organics may produce negative effects in some cases. It is really dependent on the organisms in the system. If you have a ton of corals, sponges, clams, thriving algae/macroalgae, diverse planktonic life, and etc., a skimmer might not be for you. It might very well be competing for compounds that some of organisms need to flourish. If you have a less established system full of messy fish, a skimmer is likely a great option. There is a line somewhere between those two examples where reducing or eliminating skimming is not a bad idea.

I don't buy the aeration thing as a reason to run a skimmer. While I think they can help in that area, I would not run a skimmer just for that reason. If I didn't need help limiting dissolved organic compounds & nutrients, I would use the space occupied by a skimmer for something else. That said, I can't imagine my skimmer will be going away anytime soon.
This ^ ...there are so many variables at play. And you have detailed them pretty well imo. I used to run one and it was stripping too much it seems of late. It helped me a lot over many years , but later on I discovered I could thrive a bit better without it. My nitrates and phos were zeroed for years, Nitrates now up around 5 to 7 ppm steady and still negligible Phos. My LPS corals and Softies are happier and I am seeing a bit of SPS growth, which I have never had luck with before.
As you mention the fish bioload, I have 5 fish in a 90 ( Yellow Tang, Coral Beauty, Eibli Angel, Striped Damsel and Clown) and the bulk of them have existed for almost 2 decades. So yes I am a light stocker that way but I am heavy on Inverts, of the CUC variety, you name it I've got it, perhaps this helps with bioload, combined with being a rather light feeder. My corals (I am starting to think) eat up a lot of that gunk I used to get, in fact for almost 2 years I got next to no Skimmate at all, so I decided to ditch the skimmer a while back and things are looking very good now.
Bottom line is there are many different approaches and situations as you alluded to... no sump, or fuge either here btw... I oxygenate by surface turbulence /flow and it seems to be adequate for my stocking levels, that may change in the future, all based on observations.
 
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ReefGeezer

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My tank is very new... 6 months... There are 8 fish in it it... I think the skimmer is mandatory right now.
 

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Randy Holmes-Farley

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Seems we could debate the definition of "adequate" but lets not. My point was just that I am questioning whether "complete" equivalence of CO2 between air and water is really necessary (maybe it is? - convince me)

So, if you've ever had the experience of turning off your skimmer and then seen your tank go from struggling to thriving (maybe you haven't, but I have) and drawn the conclusion "this thing is sucking the life out of my tank" then its fair to say that a skimmer could be a "negative" instead of a "positive".

Now this is not necessarily an indictment of skimming. It could just be that in the past 30 years skimming (and filtration in general) has become way more effective and even outpaced our expectations. And maybe this inertia in expectations has be influenced by interested parties (sellers of these things). And that is not even an indictment of the sellers because hey at least they are competing with each other and improving the technology and we can't really expect them not to pitch their products.

I never claimed pH control was required. I was fighting the claims that aeration is complete, which it typically is not, and in some ways, CO2 may be a useful surrogate for the harder to measure O2 exchange, which also is often not complete.

pH control is one of the frontiers of reef keeping chemistry. it is far harder to attain than stable alk or dosing trace elements, and hence we have very little data on it. IMO, it has the potential to be important since it clearly impacts how corals are able to attain alkalinity.

As the title of my thread posted earlier states: Is stable pH even different than stable alkalinity?

If corals use carbonate (or, alternatively, bicarbonate), and folks think that total alk control is useful, how could pH control not be useful since at a fixed total alk, the amounts of bicarbonate and carbonate change drastically with pH?

For me and my tank, I experienced an undesirable pH change when I turned off mu skimmer. The pH rose too much,.
 
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