The Great Skimmer Debate

[drdude05]

I was spending time enjoying my tank over the weekend, watching the tangs swim gracefully through the caves and openings of my 180 gallon SPS dominate reef, enjoying the coloration of the corals, and all in all feeling pretty good about the small slice of the ocean that I was watching which represents the realization of about 3 years of reading and research, when I starting thinking about the tank design and ways that I could make it better.

One of the things I started thinking about was skimmers, and several questions started surfacing. In all my reading for this tank, I never did find good answers for why skimmers range so much in price? Is there really that much difference in performance between a Tunze, Deltec, ASM, EuroReef, Precision Marine, and Octopus skimmer? If so, why? They all seem to be constructed similarly. Size is obviously a consideration, it takes more material to build a larger skimmer than a small one thus that would affect price. But other than that what makes a Euro-Reef skimmer more expensive than a compairable ASM or Precision Marine? Do you really get better skimmer performance by spending $100, $200, $300 more. If so what are you paying for? Better material? Better design? And if it is better, what makes it better?

[drdude05]

Another aspect that I started thinking about was skimmer design. Becket vs. Venturi vs. needle wheel vs. recirculating. When I was researching the skimmer that I have now (ASM G4X) I asked alot of questions about these different skimmer designs and as I expected, I got alot of different opinions as to what worked the best. Since I had never kept a large reef before (my previous tank was a 56 gallon) I had not paid that much attention to skimmers and how they worked. But when I made the decision to keep SPS, it become very obvious that the skimmer was a VERY important piece of equipment. I ultimately decided to try an ASM and mod it with a gate valve to make controlling the water level in the skimmer eaiser, and a recirculation mod to see if this made a difference in skimmate production. So far I'm not sure what to think as I have no real frame of reference to compair the skimmer performance to, other than to say that my PO4 levels are zero, without PO4 removal media, for the first time in 10 years of keeping reefs and I am able to keep SPS consistently for the first time as well. I assume this is due to more efficent skimming.

I guess all this ties into my previous post with the question, if skimmers are different in their performance, how do you tell? What are the signs you look for to say "this skimmer works great" or "this skimmer is a piece of junk"?

[reefermike1]

the pump that runs them, the size of the reaction chamber, and the design of the return are the 3 main factors in what makes a skimmer better imo. also being "user friendly" is nice...like unions on collection cups vs thumbscrews... and valves instead of standpipes. as far as pricing goes they will charge what people are willing to pay regardless of cost to mfg... just the way the world works, i think all skimmers are overpriced imo, some more than others for what it is.

[ckusnierek]

IMO If your looking at three or four skimmer that are all rated for the same volume, have a similiar design and basically look alike. I would say it has to do with overhead. Are they made overseas vs USA (shipping costs) packaging, some come in a plain box and some in a nice colorful box. And then there is materials... There is the extruded acrylic and cast acrylic, these things are usually out of the way and are not in danger of damage so why pay more for a tougher peice of plastic. Like I said above I think its all about overhead:
Shipping (US or china)
Labor (US or china)
Packaging (plain or pretty)
Materials
Another is R&D time, Think about the Sony PS3 and XBOX's they always significant drop in price after about a year, once they recoupe devlopment costs. Why cant they do the same with reef equipment?????

[ckusnierek]

sorry double post

[drdude05]

the pump that runs them

What exactly do you mean? What about the pump makes it better?
Bigger = better?
Needle Wheel = better?

the size of the reaction chamber

Again, bigger = better?

and the design of the return

You mean the exit from the skimmer? What makes one plumming design better than another?

[drdude05]

ckusnierek, All the points you posted are ones that I have been wondering about, but I have run across other hobbists, as we all have, that will swear that the ASM skimmer they had never worked, but the Euro reef did or vise versa. I'm looking to find answers as to why they think that way. What is different that makes the skimmer better? Is it designed better? Do they like it better because it was eaiser to setup but in reality it produces the same amount of foam, or because they paid $200 more for the skimmer they "think" it works better?

[motorslave]

Hmmm, well for materials extruded is cheaper and less desirable due to the fact that it will actually absorb a good amount of water over time compared to cast.
Pumps, well some cost the skimmer maker more vs. others so the cost is passed on. Some have better rating such as pressure ratings for a beckett skimmer. Also some have better track records and Brand Name recognition.
There are needlewheel designs that work better than others at making bubbles. This makes more contact with water so better DOC removal. Bigger chambers, more contact time better removal of DOCs again.
One thing that wasnt mentioned that is very important to the performance of a skimmer is air. How much air they can process. Without air there is no bubbles and no skimming.
As far as why skimmers that seem to have the same design having price differences, Euroreef came out with a great design, made from cast acrylic,good pumps and a great needlewheel. ASM is basically a clone, extruded acrylic etc. They made a skimmer from a design that someone else had to develope vs. just going right into production. Add to that you are talking about a product that is widely concieved as a "clone" and that also has an influence on price when you compare to an "original".
Look at Tunze skimmers, they are not the cheapest but they work well and have the benefit of some of the models fitting into some tight spaces, a very good feature in a stand.
Bubbleking. They just flat out perform.
Look at some of the cheaper models, decent performance, cheap materials, sometimes just no name pumps and design that are just copies of other skimmers. Even when a design is basically the same, it seems I see more issues posted about the cheaper made and priced skimmers by a large percent compared to the higher quality and performing units.
Then as said you get into the whole shipping, domestic vs, foriegn made issue. A factory in China can churn out cheap stuff like its nothing. Here, it cost for labor and the whole shot.
Basically, I personally will pay more for a better made product that has been tried and tested over a cheeply made clone. I have had skimmers made from extruded acrylic and have two made from cast. No comparison. And they dont just sit in a corner, they get pulled to clean. moved with system changes etc. and from experience I can tell you that a skimmer made from cast is far stronger than extruded by a long shot.

Just my two cents!

[Twitterbait]

Ok, here is my thought on the subject...

in the end the cost of materials will have the biggest impact on price. From there you add labor to build the unit and then a markup for profit. depending on the quality of the skimmer the pump can be a big part of the cost.

1. Venturi-- Cheap design and old school reliability. many of the older reefers still swear by these. simple design make these pretty cheap. they do require regular maintenance to clean out the venturi. otherwise they can be pretty reliable. skimming power really depends on the skimmer and pump used... not the best at skimming, but not as high maintenance as some of the other units
2. Needlewheel/mesh wheel-- design ranges from cheap to expensive. these will cost more for the skimming power but that power can be impressive (my mind has been changed on these) you will pay more money for skimming capacity but it is made up by lower maintenance and increased effeciency. these are for the lazy reefer who doesn't want to have to adjust the skimmer on a normal basis. the pump is a very expensive part of these skimmers but the more you spend on the pump the better the skimmer will be.
3. Beckett-- great skimming and lower cost than the needlewheel... but you will need to maintain this skimmer on a normal basis. this is a good skimmer for the hobbyiest that is already going to be messing with the tank on a daily basis. the pump is not as important as you can use any pump that is pressure rated and can deliver the required GPH. just keep in mind that there are a ton of things you have to watch and adjust for on this skimmer. good skimmer for the active hobbiest who is willing to keep it adjusted in "the zone."

there may be other types but these are the standard in the hobby and the only ones i would recommend... although it is not always the case in this hobby, with skimmers, you will usually get what you pay for. the one thing you can usually trust is to watch for the name brands, if it is a household name (PM, MRC, ASM, BM, Aqua C, etc...) then it got that distinction by performing well on many tanks.

One thing i have seen is the constant modification on the skimmers by both manufacturers and users. normally we would just be reinventing the wheel but with skimmers it is actually creating constant improvements. this is a piece of aquarium equipment that is worth tinkering with, you never know what you may come up with.

[crvz]

Originally Posted by drdude05

ckusnierek, All the points you posted are ones that I have been wondering about, but I have run across other hobbists, as we all have, that will swear that the ASM skimmer they had never worked, but the Euro reef did or vise versa. I'm looking to find answers as to why they think that way. What is different that makes the skimmer better? Is it designed better? Do they like it better because it was eaiser to setup but in reality it produces the same amount of foam, or because they paid $200 more for the skimmer they "think" it works better?

Stealing some of motorslave's points, and speaking specifically to this example, I would consider a EuroReef skimmer to be better designed than the ASM. There is little to say about the reaction chamber, as they both use common diameters and heights, but the pumps used to run them are different, as well as the needlewheel. ER takes the time to match pumps to chambers, measure and optimize airflow through their needlewheel designs, and uses better quality materials. This results in a better performing skimmer (which is loosely defined), which costs more to create (design, testing, etc).

Ultimately, though, I think a skimmers effectiveness for a given size tank is a function of the air/water contact time vs. how many gph are processed through the skimmer. Obviously you can greatly increase the contact time by limiting the flow through the skimmer, but then it's difficult to get all the wastes from the water. Likewise, you can increase flow through the skimmer, only to decrease the contact time. That's where your trades come in. You can modify an ASM to outperform a similar sized stock EuroReef with a meshed needlewheel, as the meshed needlewheel pulls more air into the reactor. A recirculating needlewheel essentially slows down the flow rate to the reaction chamber, thereby increasing the contact time and often performance. A becket, by design, has better opportunity to process more water at higher contact times compared to a needlewheel, but that comes at the price of frequent maintenance and high energy pumps.

So, to answer your original question, I think you do get more skimmer when you spend more money (mostly we're concentrating on needlewheel designs). Granted, if you're a little crafty, you can save the couple hundred dollars and modify a cheaper version to get the same result, but some folks like to have their tinkering done for them. And that costs money.

[motorslave]

Something else to consider is that no skimmer will work exactly the same on every tank. In fact that stands for many things in this hobby. You can set up two tanks identical, stock the same run the same skimmer and get different results. Just one of those things. Also another factor in the difference in success people have is the reefer themselves. Soem are better at tuning, see and rect to effects better etc.

[leveldrummer]

skimmers are one of those things that everyone has an opinions about, for me, i want a skimmer that is consistant, that doesnt need constant tuning to keep it skimming, some skimmers offer that, some dont, usually the high end skimmers are simple, work well, and skim consitantly, as you drop in price, some of those aspects go away.

[Hop]

Originally Posted by leveldrummer

skimmers are one of those things that everyone has an opinions about, for me, i want a skimmer that is consistant, that doesnt need constant tuning to keep it skimming, some skimmers offer that, some dont, usually the high end skimmers are simple, work well, and skim consitantly, as you drop in price, some of those aspects go away.

I'll have to agree And I'm alway tinking with skimmers to make them better. I've ran becketts and NWs... Never did decide which is better, but I can tell you which one was less work for similiar results

[drdude05]

So, from what I gathered so far, the general concensus is that these factors are what make one skimmer "better" than another:

1. Larger chamber. This allows for more water to enter the skimmer, come in contact with bubbles, and allow removal of DOC.
2. A pump "sized" to the skimmers chamber size. This makes sure that a good amount of water is "processed" by the skimmer. A pump that is too small will not "process" enough water, thus DOC will be missed as they float by in the sump due to the skimmer pump not feeding them to the skimmer for removal. The alternative is too large a pump that processes too much water. Is that even possible to skim "too much"? The only down side I can see to the pump being too big is that microbubbles may escape and make it into the display, the water may not have enough contact time with air in the skimmer body to allow for maximum DOC extraction, or you may pick a pump that generates too much pressure and blows the water out the top of the skimmer. This leads to the question, how can you tell when the flow to and from the skimmer is "perfect" and you have reached the point of maxium efficency? i.e. the point where the water feed isn't too slow and thus not feeding DOC to the skimmer but not too fast decreasing contact time with air in the skimmer and thus letting some DOC pass through and out of the skimmer?
3. More durable acrylic.
4. Personal preference as to ease of setup i.e. the more expensive skimmers are viewed to be eaiser to setup.

[drdude05]

It seems to me that the optimal setup would be to get the largest chamber size you can fit, add recirculation to chop the air bubbles as fine as you can get them to maximize surface area, and then add a feed pump to optimize water processing to the skimmer.