Who rates skimmers

[sphelps]

I’m not quoting anything from previous posts because it’s starting to turn into meaningless debates and arguments. Simply quoting selective parts of a statement and arguing only with those parts is fairly meaningless and doesn’t present any new information but rather disagreements.

An external protein skimmer is a protein skimmer that works externally (not in sump). When someone refers to “recalculating protein skimmers” for the most part these skimmers are external models. In sump models are not usually recirculating unless modified by the owner.

Really the 10x flow rate rule is common knowledge; many basic guides to saltwater aquariums will state a total flow rate of 10 times the tank volume is a good rule of thumb. My way of thinking is to start with the minimum requirement, which I believe is about 10x, then supplement more if needed and of course only if it’s practical. Remember I’m not arguing the fact that 3-5x won’t work but rather than running 10x will also work, personally I believe it may work slightly better but that’s not my main argument. If a tank was small enough and it did require 40x turnover a single pump system could be very practical. For example if you had a 20 gallon aquarium you could push 800gph through the overflow if you wanted, it would be better in my mind than putting power heads in which would just clutter up a small tank. However I would never see the need to run that much turnover in most tanks, especially smaller ones and of course it’s simply not practical to use a single pump to push 4000gph in a 100gallon tank.
As requested:

“As with any complex subject in this hobby, people are always looking for (and giving) rules of thumb. With regard to water movement in reef aquariums, many authors will advocate at least 10 times the volume of the aquarium per hour. So if you have a 100-gallon reef, you should be moving around 1000 gallons/hour. This is a fine starting point as long as you understand that this does not mean that you need to move 1000 gallons of water in and out of your aquarium.”
http://www.advancedaquarist.com/issu...3/beginner.htm

I love how the term dynamic equilibrium was mentioned because in my mind it hasn’t really been considered. One theory states that with lower return flow you’re going to end up with a higher concentration of organics in the sump however this would only be true for the beginning of the cycle and if a build up exists. Once steady state is reached a tank shouldn’t have a build up of dissolved organics, the skimmer should have already taken them out and continues to do so as more are added. Now the other approach is higher flow but less concentrated so at the beginning of the cycle it may take longer to remove built up organics but once steady state is reached the results would be the same. I’ll try and explain this again in another way; if you have two skimmers and one that takes in a higher concentration of organics but these organics are supplied at a slower rate and the second skimmer takes in less concentration however it’s supplied at a faster rate. Once equilibrium is reached the results will be the same. A skimmer will only filter out a certain percentage of organics anyway and at the end of the day no matter what the flow rate through the sump a skimmer will eventually turn over all the water eventually either way. So on one hand we have a lower flow rate that could possibly have a higher concentration but takes longer to turnover the tanks volume and on the other hand we have a higher flow rate which could possibly have a lower concentration but turns over the tank volume faster. The way I see it, these are the same at equilibrium. It’s like walking a shorter distance compared to driving a longer distance; the question is what are the speeds and distances and which one is faster.

The last thing I’ll note on this is in regards to this so called higher concentration, is that this is not something I really buy and would be very difficult to prove either way. A lower flow rate may take a thinner layer and if there was a build up of organics the concentration would be greater however at steady state there wouldn’t be a build up, otherwise you would need a new skimmer. In addition while it may be true that organics rise that doesn’t mean all the dissolved organics are located at the very surface of the water. On top of that you’ve got tremendous amount water flow in the display so it’s not really realistic to say you’ll see a higher concentration of organics at the surface of the water. As long as you have surface skimming you shouldn’t see a build up over at steady state. This is especially true for dissolved organics, since you know, they are dissolved.

I understand the FIFO method approach but it can’t actually be pulled off. Even with a 3 times turnover on a 100g tank you’re taking about 300gph which is too much for a recalculating skimmer and any other skimmer (made for 100g tank) that pulls in that much water isn’t going to skim out 100% of the organics anyway so no matter what you going to get bypass, and then going back to equilibrium as described above you’ll end with the same results regardless.

I’m not sure what is meant by horizontal barriers so I can’t comment on how effective they are unless an example is provided but I know placing netting inside the overflow may prevent creatures from entering the sump but could still result in death, more than likely they will be stuck on the net and not be able to return to the tank on there own. It’s very simple to come up with a solution for anything and everything but if it’s not practical it’s not a real solution. Most tanks use a vertical guard on the overflow that disrupts surface skimming for obvious reasons.

While closed loops have advantages, again they are not always practical. A closed loop and inline mechanical filters will add complications most aquarists would prefer to avoid. Also closed loops are not much more efficient at creating flow as a return pump because the majority of head loss results from plumbing. Most aquarists would prefer power heads on most tanks; they are easier to maintain, easier to install, more efficient, and provide substantially more options for flow dynamics. With a good turnover rate and added “kinetic energy” (which btw is related more to velocity than flow rate) from power heads you can filter out sufficient particulate matter without the use of complicated closed loops and mechanical filtration. Remember less is more
Also in regards to efficiency this can be approached many ways however I will use my tank as an example. I run a return pump and two tunze power heads, if I drop a size in return pump I’ll save 17W and loose over 500gph, if I make that up with another power head how am I saving power? I’ll actually be using about the same but I’ve added more clutter, complication and maintenance to my tank. As stated my tank uses one return pump and two power heads, the return pump puts out about 1000gph with head and is rated at 65W (although I’m sure it’s using significantly less power) and my tunzes pulse so I’ll assume an average of 3000gph at 45W combined. That’s 110W or less for a 40X turnover on a 100 gallon tank. I’d like to see less power used and better flow on the same size tank using a smaller return pump and a closed loop. But I certainly wouldn’t want to see what it looks like.

I’m not looking for math or sources to back up claims, mainly because I don’t care that much but also because I’m not disagreeing. I know may people just love to argue but that’s not my goal here. Honestly you can use pretty much whatever flow you want for a sump turnover and my argument is that it doesn’t matter. Yes lower turnover rates are quieter and for this reason more common because higher flow rates require more experience to achieve quieter results. In addition lower flow rates require cheaper internal pumps; high flow pumps are more expensive and for the most part louder.

The two main arguments aren’t really that different, one argument is for 5x and the other is for 10x, however my argument isn’t really an argument. I’m not set in my ways but rather I believe advantages and disadvantages exist for both but really we’re not talking about a huge difference here. I’m going to say something and I honestly hope it doesn’t offend anyone but from my limited experience in both this hobby and my career, I have found that too much experience can be a bad thing. The main reason relates to the old saying, you can’t teach an old dog new tricks. This holds true in many cases, lots of guys I work/deal with are extremely reluctant to change and are set in there ways. Not that their ways are necessary bad but sometimes advancement and technology provides new opportunities and methods worth trying. For example how long have people been using the Herbie style overflow? Before this style of overflow it was virtually impossible to create quiet and bubble free high flow returns so nobody did it.

I’ve said it over and over again and feel now that I’m really beating it too death but a flow rate of 3-5x will produce success and so will 10-15x there really isn’t much of a difference. Skimmers are independent and other parts of the sump filtration need to be designed for a certain flow rate. What that flow rate is, is completely up to the owner’s or maintainer’s preference and there is no real scientific evidence to support either option.


Mr. Wilson, the way you compare TOTM to show n shines is completely irrational in my books. You can fake a car; it can be really nice but not work at all. Also they really only go together in one way until you get into customizing but the same rules apply. You can’t really fake success with a marine tank, you can clean it up a little but in the end you can’t fake it. In fact most will always say it looks better in person. Why do so many people now love using T5 lighting? I can guarantee you it’s because of all those beautiful European tanks. It doesn’t mean you’re guaranteed success and the same results by using them but it sure as heck shows they work. That’s my point with TOTM, sure nothing guarantees anything but if almost all successful tanks use something it probably works pretty good or at least you can’t say it doesn’t work.

Also I did see your webpage but was hoping to see something with a little less fluff. Not trying to prove anything but I was hoping to see examples of the filtration techniques you exercise and the mature tanks that prosper from it. I only ask out of curiosity as some of your techniques both scare and fascinate me. I can guarantee that Mods won’t object to you posting some pictures of your previous tanks, whether you owned them or not it wouldn’t be considered advertisement. Plus I’m sure after 30 years you’ve owned your fair share of aquariums.

[golf nut]

I am not sure if you noticed, but if you continue to read the article from the magazine you quoted you will see the following, if you read further you might find that the writer is actually advocating against 10x through the sump rather 3x or 4x is better..

As with any complex subject in this hobby, people are always looking for (and giving) rules of thumb. With regard to water movement in reef aquariums, many authors will advocate at least 10 times the volume of the aquarium per hour. So if you have a 100-gallon reef, you should be moving around 1000 gallons/hour. This is a fine starting point as long as you understand that this does not mean that you need to move 1000 gallons of water in and out of your aquarium.
Many reef aquarists use some sort of overflow in the tank to take water to an external container called a sump. In the sump various tools such as protein skimmers, carbon containers, reactors, etc. filter the water. The water is then returned to the aquarium. This is referred to as an open loop. The volume of water that flows through this loop need only be 3-4 times the volume of the tank (not 10+). This is the filtration flow rate. The rule of thumb that was mentioned earlier refers to the circulation rate in the aquarium. This number takes into account, not only the return from the filter, but circulation from various other pumps as well. I cannot tell you how many times people have come to me and asked how they can quiet there filter down on their 90 gallon tank because they are trying to put 900 gallons/hr through their overflow.
http://www.advancedaquarist.com/issu...3/beginner.htm

[sphelps]

Originally Posted by Mr OM

I am not sure if you noticed, but if you continue to read the article from the magazine you quoted you will see the following, if you read further you might find that the writer is actually advocating against 10x through the sump rather 3x or 4x is better..

Yes I did notice, did you notice the reasoning (noise not performance) and the fact it has nothing to do with my argument or why I quoted that? Like I said before some just love to argue but I didn't say 3-5x was wrong just that it's not a requirement and 10x will work equally well if you can deal with the higher flow. Also note the date of the article.

[golf nut]

Originally Posted by sphelps

Yes I did notice, did you notice the reasoning (noise not performance) and the fact it has nothing to do with my argument or why I quoted that? Like I said before some just love to argue but I didn't say 3-5x was wrong just that it's not a requirement and 10x will work equally well if you can deal with the higher flow. Also note the date of the article.

You appear to be confirming your 10x turnover sump rate theory, however the article simply claims that 3x is adequate, otherwise they would have advocated a 10x capacity and explained how to select the correct size pipe for a silent overflow

[sphelps]

Originally Posted by Mr OM

You appear to be confirming your 10x turnover sump rate theory, however the article simply claims that 3x is adequate, otherwise they would have advocated a 10x capacity and explained how to select the correct size pipe for a silent overflow

Like I already stated, it takes more experience to run higher flows through overflows properly, it's not for everyone and it's not necessarily better than lower flow. That article is for beginners, which you would have noticed if you read the title rather than immediately trying to find something to argue with. I would never tell a beginner to use 10x turnover just like I wouldn't tell one to use a herbie overflow either.

[golf nut]

You quoted the article to back up your statement, I am arguing no more than you are.

I have always promoted low flow, and have used syphon systems for many years, I have never advocated a Durso, a Durso is for people that have incorrectly sized their drains.

Please refrain from accusing me of making this a personal issue.

[sphelps]

Originally Posted by Mr OM

You quoted the article to back up your statement, I am arguing no more than you are.

I have always promoted low flow, and have used syphon systems for many years, I have never advocated a Durso, a Durso is for people that have incorrectly sized their drains.

Please refrain from accusing me of making this a personal issue.

Perhaps you could read things properly before making your arguments, if you did you would realize that quote had very little to do with my points. It was only intended to show that 10x is a general rule of thumb for total flow, nothing more.

[mr.wilson]

I read the previous post you are talking about and I didn't see anything that you haven't said in this thread, so I agree we don't need to revisit it.

Everyone uses different terminology. I consider internal skimmers ones within the aquarium, which fell out of fashion 10 years ago. External skimmer is assumed, so I haven't heard the term in a long time. I locate external protein skimmers in sums to catch drips, overflows, and act as a fail-safe.

A 10x flow rate through the sump to be an industry standard or common knowledge. I did a search on Wet Web Media and the first article that came up was this one which recommends a 3-5x throughput. http://www.wetwebmedia.com/circrat.htm

I'm not arguing that a 10x throughput won't work, only that it is inefficient and a poor use of resources. An 800 GPH pump is suitable for a 200 gallon tank as a sump return. I don't agree that it would be a good choice for a 20 gallon tank.

Protein skimmers are limited to removing a maximum of 25% of the TOC so there will always be a buildup of dissolved organics that the protein skimmer cannot process. Your example of the two skimmers doesn't apply to our discussion of how much water to move through the sump. If you believe Escobal's theory that the proteins need a two minute dwell time for optimum bombardment time, then the skimmer with a more concentrated feed and longer dwell time will be more efficient than the second example you offered where less concentrated water is processed quicker. The two schools of thought are filter the water slowly and thoroughly, or quickly and less thoroughly. I agree there is an argument for either method, but the subject at hand is "do you move more water through a sump than the amount the protein skimmer will process?".

The secondary question is do you use a sump design that guarantees the skimmer processes the water only once before returning it to the display tank, or do you allow the skimmer to process the water numerous times while new unprocessed water bypasses it?

A higher volume turnover (10x) will cause the water passing over the overflow to crest higher. You will have around 1/2" of water skimmed from the surface. With half of that flow (5x) you will have 1/4" skimmed from the surface. The extra 1/4" collected with a larger pump will not move the surface water any faster, it will only dilute the surface film collected. Allowing half of that diluted water to bypass the protein skimmer due to an oversized return pump, coupled with a sump design that allows the water to be reprocessed over and over makes the system even less effective.

A horizontal barrier for an overflow is a piece of horizontal acrylic, eggcrate or glass that sits above the overflow edge perpendicular to it. It acts like a long slot rather than a series of small slots. It stops fish and inverts from getting through the same as vertical slots. Nothing gets trapped in the dry part of the overflow. The other way of draining without losing half of your surface area and breaking surface tension with teeth is to have a smooth overflow edge and place gutter guard mesh just inside the overflow box. As there isn't a gap, nothing will get stuck in the overflow and dry out.

There is no head loss with a closed loop even if you locate the pump in a basement because the intake is at the same height as the return. There is some friction loss if you use too many elbows, but Tigerflex hose minimizes it. Powerheads are a poor choice for added flow because they do not have adequately diffused intakes so they can injure livestock. They also cause heat transfer, vibrations, stray current, and poor flow dynamics. An external pump closed loop has a higher upfront cost but lower operational cost and more longevity (10-20 year pump life vs. 4-6 year pump life). The popularity of powerheads stems from low $50 increments needed to implement them. If you are on a budget, they get the job done without major drawbacks, but in the long run the cost more, require more maintenance and are less efficient.

Your current return pump RE65m3 (1717 GPH @ 65 watts) moves approximately 10x the volume of your display tank. If it was replaced with an RE25m3 (660 GPH @ 38 watts) it matches your skimmer pump which I estimate to be about 500GPH, and you would save 27 watts. Prop powerheads are not accurately rated for water movement so the flow rates the manufacturers offer, but let's assume they are accurate for the sake of discussion. You claim you are getting 3000 GPH @ 45 watts from the two powerheads combined. Using your numbers, you could add another powerhead for 22.5 watts and add 1500 GPH flow to make up for the 500 GPH you are dropping by matching the sump turnover rate with the protein skimmer intake. You would have a net gain of 1000 GPH flow with no bypass of the protein skimmer. There are numerous benefits for draining less water mentioned already.

A closed loop system offers the following benefits if executed properly...
1) Hidden influent and effluent lines.
2) Less heat transfer.
3) Less chance of stray electrical charge or shock hazard.
4) Less vibration.
5) No electrical cords in the water or running over the top of the tank.
6) Easy access to intake strainers.
7) More laminar and less turbulent flow for better inertia.
8) The ability to position flow anywhere in the tank.
9) Easy removal of pump if necessary.
10) True flow volume ratings.
11) High pressure flow.
12) Long pump life.
13) Only one cord to plug in.
14) Better circular flow.
15) The ability to locate the pump in a remote location (service area).

I make my technology and methodology decisions based on a thorough thought process, not based on my 30 years of experience in the hobby or 22 years experience in the aquarium industry In the 70's & 80's we used a 3x total flow rate for the display tank. In the 90's, a 10x flow rate became commonplace (likely the source of your information), and in recent years 20-40x has become the acceptable range. From my experience quality is better than quantity. If you use powerheads randomly aimed at the rock formation or front glass, you will need 40x flow to get the results you are looking for. If proper flow dynamics are implemented (circular flow, laminar flow, and up-flow for suspension) then you can get by with as low as 15x the volume of the tank for total flow.

The Herby method of draining was common in the 90's. It fell out of fashion after the Stockman and Durso modifications were introduced ten years ago. The problem with the Herbie method is it allows for a small drain point (one you can't even monitor) that can potentially clog. A safer system is a true siphon drain with a Stockman or Durso emergency drain.

I don't think you can fake a car in a car show or a tank in a TOTM. My point was a TOTM is a chance for everyone to see a nice tank that is successful, not a chance to follow the owners learning curve. You will see every possible method with good results. As a result, it's hard to measure their success and decide on the merits of the system. TOTM owners aren't required to explain or defend their methods. It's just raw data with a few anecdotes. I read a lot of books and articles and spend a lot of time on forms. I just don't have time to read a TOTM write up. I skimmed your tank build thread, but I would have read it if I was on this site as it played out. I guess news is more interesting than history to me

Europeans don't use T5 because it's better, but because it's cheaper. I lived in Europe for the last year and I can tell you from talking to hobbyists and industry people, MHL is preferred. T5 picked up some interest a few years ago, but they are waning in popularity now. Hydro rates are much higher in Europe, as is fuel. They all drive diesel over there (which I prefer) but they wish they could afford our gas guzzlers.

My clients look for aesthetics (or fluff as you call it), not fancy equipment or rare livestock. There is no point in putting filtration details on my website. I have lots of pictures posted on other forums (RC etc.). I prefer to modify cost effective filtration devices and lighting, rather than throwing money at overpriced equipment and haphazard configuration of it. I don't do maintenance or much in the way of stocking so I don't have many pictures of mature tanks.

[Canadian]

Originally Posted by mr.wilson

A closed loop system offers the following benefits if executed properly...
1) Hidden influent and effluent lines.
2) Less heat transfer.
3) Less chance of stray electrical charge or shock hazard.
4) Less vibration.
5) No electrical cords in the water or running over the top of the tank.
6) Easy access to intake strainers.
7) More laminar and less turbulent flow for better inertia.
8) The ability to position flow anywhere in the tank.
9) Easy removal of pump if necessary.
10) True flow volume ratings.
11) High pressure flow.
12) Long pump life.
13) Only one cord to plug in.
14) Better circular flow.
15) The ability to locate the pump in a remote location (service area).

How about propeller pumps like Ecotech Vortechs or Tunze stream pumps? They address most of the cons of powerheads and consume significantly less power than a closed loop.

[golf nut]

Originally Posted by Canadian

How about propeller pumps like Ecotech Vortechs or Tunze stream pumps? They address most of the cons of powerheads and consume significantly less power than a closed loop.

This would make a great discussion.