Pros and Cons of SKimmers

[Europhyllia]

Anybody in the mood to discuss the pros and cons of skimmers?
Here's an interesting article to get things started:
http://www.advancedaquarist.com/2010/2/aafeature/view?searchterm=skimmer

[hobogato]

ok, it is way too close to summer for me to read something like that! my brain hurts (oh no, i sound like my students).

joking aside, it is an interesting study. there is plenty of anecdotal evidence on both sides of the "to skim or not to skim" argument. personally, i have noticed that successful systems with a skimmer are definitely achievable, but successful skimmerless systems are also attainable. there is just a fundamental difference in feeding, maintenance, and supplementation that go with them. also, since there are many more variables to a system, the skimmer or lack thereof just seems to be one of the many things to think about.

[txg8gxp]

My brain hurts now too....There is alot of good info there, I'm really surprised at how low amount to TOC is removed. 34% dry don't seem all that great to me. I also am shocked at the amound of calcium, magnesium, etc. that is removed aswell. Kinda sounds like skimmers might be more money and work then needed. Seems like you could maintain those numbers just with a water change, but maybe not. I didn't like how much cal/mag was removed, no wonder you have to run 2 part or a calcium reactor on most systems. Good link, it is nice to see some real numbers and data. With reading several nice articles on SW I'm starting to like ace's setup more and more.

[saabtech]

!!!!!!

Happy 3,000th post!!!!!!!!

[txg8gxp]

I think this might be a article for the maast library.

[Europhyllia]

personally, i have noticed that successful systems with a skimmer are definitely achievable, but successful skimmerless systems are also attainable. there is just a fundamental difference in feeding, maintenance, and supplementation that go with them. also, since there are many more variables to a system, the skimmer or lack thereof just seems to be one of the many things to think about.
lol are you running for office?
I was hoping for more of a 'what is gained by skimming/what is lost by skimming' response... ;)

[hobogato]

the problem is, i have had tanks with skimmers that did really well, and my current tank seems to be doing well without. hard to pick a side of the fence when both yards can be nice and green ;)

[txg8gxp]

hard to pick a side of the fence when both yards can be nice and green ;)
hahaha, that's a good one.

[Europhyllia]

no no I'm not looking for preferences. I was trying to make sure I know about all of the potential things that PS can add or remove.
For example I like that they add aeration especially since I am using the biopellets for example.
I don't like that they would also remove my phyto.
And potentially Mag and Calc as well.

[hobogato]

actually, the aeration is debatable. i dont remember where i read it, but i remember reading an article a long time ago that said the DOC was only negligibly affected by the presence of a skimmer. that article did however point out that a skimmer helps keep the film off of the top surface of the water which allows for better gas exchange across the surface area of the tank. as long as the surface of the tank was kept clean by agitation, the DOC with and without a skimmer running was nearly the same. i wish i could remember where i read that stuff...

[hobogato]

on the flip side, that is a definite drawback of a skimmerless setup. the stuff that the skimmer would be pulling out of the water tends to concentrate in a layer at the top of the tank. that is something that your maintenance routine would have to take care of.

[Europhyllia]

The instruction for the biopellets state that it's best to put the pellet reactor output right by the skimmer input or else it was possible to experience a pH drop. People who had experienced the pH drop stated it was fixed when they did that

[hobogato]

well, that makes sense. i am sure the DOC is higher right out of the skimmer. the article i read was talking about the DOC in the display tank - not adjacent to the skimmer output.

seems that adding an air stone to the sump near the intake of the biopellet reactor might accomplish the same thing?

[Europhyllia]

I don't know. Maybe for people that already have a skimmer just leaving the cup off would provide the aeration without sucking out the good stuff?
Or maybe using a skimmer rated below tank size used.

[txg8gxp]

Why couldn't you just use a air pump and stone?

[Europhyllia]

I think skimmers are much more effective at producing a high volume of very small bubbles. Seems like air stones produce generally much larger and fewer bubbles than a good skimmer (or even just the pump/air part of a skimmer) hence I think aeration and pH stabilization in regards to pellet reactor effluent would be much more effective with that than with an air stone IMO.

[txg8gxp]

Good point, then with that said...if you had a good bubble trap in your sump you could run just a needle wheel pump for aeration if you wanted to go without a skimmer. Is there any flaws with that?

[CoryDude]

Good aeration is better provided by gas exchange at the water's surface on your tank. If you were to take the Riemann's sum and try and figure the micro bubbles total surface area inside the skimmer, you're still limited to the total volume inside the skimmer, assuming the bubbles are small enough and occupy 100% of the skimmer reaction chamber.

All that mumbo jumbo aside, you'll have better results w/your biopellets using a skimmer from the increased oxygen content, in my experience. I tried running my bacteria system w/o a skimmer for a few weeks last years. Everything looked fine for about 2 weeks, and then I had an algae explosion. Just my experience with the two options.

[jroescher]

I would imagine that an air stone or needlewheel pump outside of a skimmer would cause insane amounts of salt creep and corrosion. Also, It was my understanding that the skimmer's function was essentially the same as what occurs in nature by the waves and the foam that they create.

[StevenSeas]

Also, It was my understanding that the skimmer's function was essentially the same as what occurs in nature by the waves and the foam that they create.

that is exactly correct the currents was away the dirty water from the reef and then wash up and crash on the bluffs and beaches and produce that nice lovely foam that we all love the smell of just soo much. The waves crashing and producing foam is mother natures huge foam fractitioner or protien skimmer. So in my opinion I think if it is good enough and works for mother nature I will use one. I'm not saying the studies arewrongbut I think that they weren't measuring specific dissolved organics and then seeing how the impact the reef environment.

[Jordan N.]

that is exactly correct the currents was away the dirty water from the reef and then wash up and crash on the bluffs and beaches and produce that nice lovely foam that we all love the smell of just soo much. The waves crashing and producing foam is mother natures huge foam fractitioner or protien skimmer. So in my opinion I think if it is good enough and works for mother nature I will use one. I'm not saying the studies arewrongbut I think that they weren't measuring specific dissolved organics and then seeing how the impact the reef environment.

While I'm sure that wave action does remove some nutrients in the real ocean I would hesitate to say it was a major part of keeping the water clean. I also imagine that a lot of what is removed would likely make it back into the water during high tide or the next rain storm.

IMO, the natural reefs filter the water in two main ways --dilution and bio-diversity. The first is pretty obvious, there's a lot more water in the ocean than in our tanks so it keeps organic concentrations down. The other factor is just how competitive of an environment the reefs are. The nutrients are constantly consumed by another organisms, Isopods, bristleworms, lionfish, sharks, coral, ect.

As far as the skimmer question goes, I don't use one personally. I used coralife when I first set up my tank but I took it down after about a month because it was so finicky. (I was having to adjust it twice a day.) I never saw any real change after that --if anything my algae problems improved but I attribute that more to my tank getting mature. I do have a light Bio-load though, at that time 2 fish.

In general I think skimmers are overrated --they probably help if you feed a TON or run a bare bottom tank but are just unnecessary in my experience.

[allan]

Well, I put a skimmer on after spending a lot of sleepless nights wondering if I was going to 'crash' due to my negligence. Since I've been running a skimmer I've not had any issues... but I didn't have any before either. My bottom line is that if a skimmer does remove any waste whatsoever (and I'm convinced that it does in light of that dark texas tea smudge that collects in the cup), then whatever the percentage I'm in. If for no other reason than it helps me sleep at night.

But as Jordan mentioned above, I do feed a lot and I have a lot of fish. I think. Not sure what is a lot.

As far as aeration, I like the surface agitation but since I run T5s I concentrate my agitation in the sump. I was thinking of adding more agitation down there on a nightly schedule to increase O2 during lights out in the DT.

[Mr Cob]

Nice thread.
Like Ace, I have tried various combinations to include; skimmerless, rated skimmer, over rated skimmer and my current setup of a seriously under rated skimmer. All with successful results.

After reading this thread, the article and my own personal experience I think I prefer the “under rated" approach (for a mixed reef).

My opinion would probably change if I had a SPS only tank or FO tank or even a FOWLR setup.
I think a lot of reefers will overlook surface agitation for aeration. How about your overflows and water moving over baffles….that provides a lot of aeration in itself. I think with those contributing factors using an air stone and pump is not needed if you are not running a skimmer or using an under rated skimmer.

I’m also big on surface agitation and currently point a couple of koralias at the surface. I have been running my current system (144g) since October of 2009 with at first a Saphire Aquatics nano skimmer, and for the last 3 months with a HOB nano BakPak skimmer hanging on the sump. It pulls nasty stuff daily and I have it skimming dry…change it every couple of days. So, with this configuration I know I’m not going to over skim the system but I will still be contributing to the removal of some of the excess nutrients. I also feel comfortable that with the combined efforts of the skimmer, surface agitation and my weekly water changes everything remains pretty stable.

Because of this I don’t have to dose a two part or strive to keep up with calcium….however I should note that I did just recently start dosing Fiji Gold about a month ago, once a week only because it’s 100% natural and not really much of a chance of overdosing.

Anyways, my approach to reefkeeping has never been very scientific or complicated, I try to keep things simple and use the least amount of equipment and dosing as possible. Perhaps if I didn't have a "budget" that would change. I rely heavily on water changes and “love”. The more I stare at the tank the more it seems to thrive J. Seriously…go try it.

[Europhyllia]

Rob, I just came to the same conclusion. An underrated skimmer will give me the immediate oxygenation for my bio pellets without removing too much of the good stuff. I think for my set up under rated skimmer might be just the perfect compromise.

[txav8r]

I have to admit that I laughed when I saw the nano skimmer in Rob's 144 gallon tank but It was hard to laugh too much because his tank looks great.

[Mr Cob]

^yeah I was a little embarrassed for the longest time! Thanks for not laughing. Shoot, first time I met Giau (aquasport) he laughed abnormally when I opened my cabinet to show him my sump on my old 120g. I had couplings everywhere because I kept measuring my cuts wrong with the PVC.... yeah, I don't hard plumb anymore...pure tubes now :)

Karin, I agree completely. I also think that each tank and owner habits will dictate what works best for each system.

[allan]

You know I used to run my ozone through my skimmer, but now I run it through an airstone. Anyone know why it's advised to use the skimmer? I was thinking the bubblles, but an airstone provides those bubbles right?

[Europhyllia]

to me air stone is big bubbles and less of them. skimmer is tons of little bubbles and more efficient because of that.

[txg8gxp]

Some air stones produce nice small bubbles, but the down side is they need to be replaced ever month or so.

[hobogato]

You know I used to run my ozone through my skimmer, but now I run it through an airstone. Anyone know why it's advised to use the skimmer? I was thinking the bubblles, but an airstone provides those bubbles right?

the skimmer acts as an ozone reactor, keeping it in there rather than in your tank. as long as you have a pretty good distance between the ozone air stone and your return pump you should be ok, especially since you are not using it very much. the skimmer keeps excess O3 from getting into the display tank and causing problems.

[allan]

You know that chamber immediately after the inflow chamber? That's where I have the air bubbles coming in. From there it goes through the refugium section, then into the filter part where the filter media is, and then to the return section. I almost put it in there, but previous experimentation with air stone to increase oxygenated water proved that those little bubbles end up in the pump, sliced and diced, and end up in my DT.

I could put it in the chamber where the water from the DT goes into...

[hobogato]

it is probably fine where you have it

[Ping]

Another reason for putting the ozone through the skimmer is the ability to run any air leaving the skimmer through carbon. Ozone released directly into the tank and then into the room is a health hazard for both the tank inhabitants and anyone in the area of the system while the ozone is running. The main reason to use ozone is that it helps a skimmer produce more skimmate.

I believe going skimmerless is a technique only to be used by advanced experienced aquarist, not just book smart aquarist'. Long term success of a skimerless system requires all or a combination of the following: Small bi-weekly water changes - a very large algae refugium - a one year or older 20 gal or larger, live rock no light refugium (I can’t remember the name of this) - or the use of a large algae turf or algae waterfall scrubber and a small amount of carbon.

Most of the gas exchange in our closed systems occurs across the surface of the display. Most important of these exchanges is the off gassing of CO2 and its subsequent pH affects. In a normal natural system (not the latest fad aimed at water quality), a system that contains sufficient quantities of live rock and a sand bed; all that is required for sufficient gas exchange is a method for skimming the smothering material off the surface of the water (not foam fractioning) and mixing this material back into the water to be consumed by bacteria and higher life forms.

The need for airstones and bubblers to create water movement and water mixing has been replaced by our powerheads and surface skimming. Airstones and bubblers only create the excessive salt creep we had before modern filters and powerheads.

[hobogato]

nice one peter!


...live rock no light refugium (I can’t remember the name of this)...
are you talking about a cryptic fuge?

[Ping]

Yes, thanks Ace.

[Ping]

Sorry to keep bumping today, I am finally getting my head back on as well as getting my mind back into the aquarium thought process.

Fine air bubbles from an air stone are beneficial in the sump of a skimmerless system. The large quantity of micro-bubbles produced by an air stone will aerosolize some of the phosphates. This should be done in a semi closed container to contain the salt creep. This is why small and inefficient skimmers are better than nothing.

My next large system will have several types of refugiums for filtration and plankton production, but I will still put a skimmer in place and run it on a very dry setting.

[Mr Cob]

Great info Peter, helps explain a lot....for me at least.

[StevenSeas]

the skimmer acts as an ozone reactor, keeping it in there rather than in your tank. as long as you have a pretty good distance between the ozone air stone and your return pump you should be ok, especially since you are not using it very much. the skimmer keeps excess O3 from getting into the display tank and causing problems.

Also Ozone does something that not many people think about at all. Organic compounds with double or triple carbon bonds (majority have atleast 1 of these) when treated with O3 gets cleaved in half around where the bond is, so if there are a lot of those bonds they get broken up even more. The compounds get broken up by the ozone which makes them have less weight individually so it is easier for the bubbles to take them to the top and pop and send them into the skimmer cup. This decreases dwell time needed to remove some of the largest/longest organic molecules. Thats why people that properly use Ozone on a properly sized skimmer hooked up right tend to get a decent amount more of skimmate.
That is on top of the other benefits that have already been stated like pH etc

[Europhyllia]

great thoughts guys. Really appreciate this discussion... ;)

[dclegern]

If using a skimmer, should it be run constantly? Or one week at a time? only at night? blah blah blah......

[Ping]

All the time.

[Europhyllia]

If using a skimmer, should it be run constantly? Or one week at a time? only at night? blah blah blah......
I sometimes turn off the return pump to the sump (when I feed phyto for example) but I always leave the skimmer running. Ace brought up a good point about stagnant water being able to cause problems.
So with my system the DT has water cycling and the sump has water cycling only that for a couple of hours the two are not connected.