Beckett vs. Needlewheel skimmers

[JC VT]

Hahn, it looks like you are up late like me

what if the skimmate was darker AND in the same volume or greater?

It's a big what if. I don't think people who skim dark have an equal volume as those who skim wet. I can look at my skimmer now and say that the cup would fill up MUCH more slowly if I skimmed dry.

If you take that old pooh, sediments, mulm, and detritus and stir it up, then you would expect more dark skimmate to be produced

Then it looks like it hasn't broken down yet.


IIRC healthy stony reefs have extremely low concentrations of dissolved organics, but high concentrations of available foods. I think this is a good model to follow.


Besides, fish poop is what my sand sifters need to stay alive, and sooner or later that poop will give off its oils and proteins for the skimmer to capture

Ecological rule of tens Your sand sifters can only take 10% of the detritus/whatever as food and then excrete the other 90% out as more detritus. Detritus eating organisms just don't take up detritus and then not poop. They poop too.

 

[hahnmeister]

<a href=showthread.php?s=&postid=8303315#post8303315 target=_blank>Originally posted</a> by JC VT
Hahn, it looks like you are up late like me

yep, you get my last 1/2 hour here before bed...lol.

what if the skimmate was darker AND in the same volume or greater?

It's a big what if. I don't think people who skim dark have an equal volume as those who skim wet. I can look at my skimmer now and say that the cup would fill up MUCH more slowly if I skimmed dry.

Oh, I totally see where you are coming from. Most of the time when people change from wet to dry skimming all they are doing is adjusting the skimmer's water level. Im talking a change on a much larger scale though... making the skimmer recirculating (more CFM's), feeding the overflow water directly to the skimmer, and slowing that rate down. This will make a much larger impact... not even that the result is dryer or wetter, I know its an instant association for most but in this case I really mean just darker.

If you take that old pooh, sediments, mulm, and detritus and stir it up, then you would expect more dark skimmate to be produced

Then it looks like it hasn't broken down yet.


Oh, come on! Its been sitting at the bottom of my tank for months already! If its going to take longer than that, you really dont have a case here because rather than use the skimmer Ill just suck it out when I do a water change... :lol: Im just going to say I dont think darker means older here.

IIRC healthy stony reefs have extremely low concentrations of dissolved organics, but high concentrations of available foods. I think this is a good model to follow.

It seems sound, yes. So in that case, we should leave things that these coral's feed on, or things that the things feed on that the corals feed on... which is what skimmers remove. Wait a second...

Besides, fish poop is what my sand sifters need to stay alive, and sooner or later that poop will give off its oils and proteins for the skimmer to capture

Ecological rule of tens Your sand sifters can only take 10% of the detritus/whatever as food and then excrete the other 90% out as more detritus. Detritus eating organisms just don't take up detritus and then not poop. They poop too.

The ecological rule of 10's >>> "Only 10% of the energy in a trophic level is passed on to the next trophic level." Nice try there, but you are interpreting it backwards I think. Conservation of energy and mass would show this to be false in a balanced eco-system (they cant poop more than they take in, lol), but the idea comes from the notion of the food chain resembling a pyramid where the net weight or number of organisms that are needed to support the next level up on the food chain is 10x. "The 90% energy loss at each trophic level goes to the metabolic needs of the organisms at that level." So if a sand sifter takes in 1 pound of poop, its going to process 90% of the energy from that poop before it passes (in theory). The net result is still less poop. Lol. Sorry, Im having giggles as I type this thinking of starfish with constipation problems... I think its just best to say that the ecological rule of 10's here doesnt apply. If you read the rule closely, "Nutrients behave quite differently than energy; they tend to cycle and recycle within ecosystems". So in effect, you have used the rule of 10's as an argument for not skimming all together...lol. Here are the details in case someone wants to know... http://www.uncg.edu/bio/ConBio105/info/TrophicLevels.htm
If the rule applied as you say, the world would be a never ending stockpile of crap... Worms, snails, starfish, etc... they do break down the waste of other organisms and convert it to a 'lesser evil', or food for the next organism FWIW. Sure, its still detritus, but with less phosphates, less proteins, etc. I suppose you meant that its 'more detritus, less nutrients'... well... isnt that what we want? Besides, the more they deal with it, the closer it is to being completely broken down into nothing but neutral sediments, or food for denitrification.

"Nutrients behave quite differently than energy; they tend to cycle and recycle within ecosystems". The very idea of NNR proves this to be true. Most of the organisms that eat detritus and waste from the reef (okay, now we are getting into that area where the argument is 'what is waste?' as one organisms waste is another's food)

I dont mean to poke fun if this reads like I am, Im really not. If anything you are sending me off to sleep with funny images in my head. Im imagining 'what if it were true' and thinking how funny it would be to see a snail needing turbo-lax.

 

[JC VT]

you really dont have a case here because rather than use the skimmer Ill just suck it out when I do a water change...

What case did I have? I wasn't aware that I had one regarding siphoning vs skimming.

we should leave things that these coral's feed on, or things that the things feed on that the corals feed on... which is what skimmers remove. Wait a second...

You're not implying that we should run skimmerless to 'leave things that corals feed on' right? Why run a skimmer in the first place?

Worms, snails, starfish, etc... they do break down the waste of other organisms and convert it to a 'lesser evil', or food for the next organism FWIW. Sure, its still detritus, but with less phosphates, less proteins,

Why leave rotting detritus in the system in the first place? LOL
Before it gets to your starfish, it's being decomposed by bacteria. After your starfish poops, it's being decomposed bacteria. Why have an army of detritus eaters that just adds to your bioload?


So in effect, you have used the rule of 10's as an argument for not skimming all together...lol.

Not really It supplements my argument perfectly. I prefer to remove the food source and cut off the rest of the organisms from their food source.

 

[hahnmeister]

1. No big deal, you just mentioned that the organic matter must not have been broken down enough to produce the darker skimmate... and my response was... gee wiz, its been there for a couple months now! How much longer should I need? OR, if thats the case: that it takes that long for detritus to give off the organics that make darker skimmate, then just forget the skimmer all together and Ill just siphon rather than skim.

2. Many people do run skimmerless, yes, that is the implication. Im just saying, its a contradiction.

3. why not leave it in the system then? one organism's food is another's waste. For a complete ecological cycle in our reefs, removing anything would seem a bad idea. It is however impractical for people with mini-reefs because there just isnt enough room for everything needed. You say 'waste' and 'danger', I say 'food' and 'more diverse ecosystem'.

4. so you want to starve your corals except for the manual feeding you give them? Ok, I see how you like to run your tank. You are in the 'export everything' crowd. Nuf said. Im not, thats all. Heck, I turn off the skimmers 3 days out of the week for plankton/pods/etc to do their thing and I havent had a problem. I have had a remote plenum tank, DSB, BB, etc. I currently run a combo of skimmers and fuges with macros, and try to apply 'just enough' of each branch of thinking to get a balance within the reef. I myself dont think of my skimmer as a mechanical filter... there are plenty of other things that do that, including the critters in the tank that would love a fish-poop to feast on for a day.

 

[Roland Jacques]

Old poo, new poo, brown poo, blue poo.
Who knew, that you two, would know so much about poo poo. LOL.

So thier you go Alwest now go buy a skimmer

 

[kentrob11]

A quick chime in...While most of my skimmer building efforts have gone into NW skimmers, I will say that the best performing skimmer I have ever seen was a dual recirculating beckett made by Geo run with a 200gph blueline pump. that thing pulled out some serious mud but had the same problems other becketts seem to: major cleaning issues. I think that a recirculating beckett similarly sized with a bubble diffuser, coned riser and a wetneck would prove to be the best skimmer out there even if it did use 20% more electricity to run....Anyone want to build one?

 

[bergzy]

pictures...we need pictures of direct nw and beckett use on the same system!

well, here is mine...

though the becket is huge and the nw is small, one can see the difference in skammate quality and quantity.

the one gallon jug is 6 hours on an aerofoamer 830 powered by an iwaki 55rlt (i have sinced upgraded to an iwaki 70rlt) and the little euroreef 5-2 with a sedra 3500 shows the nice dark skimmate amount after 48 hours of use.

why run two (had two nw's on board but i fried one of the er's) different type of skimmers? for exactly the reason you see in the pic. different quality and quantity of skimmate.

 

[alwest45]

Too much work. I think I'm caught up now on the thread. And it's still not all clear to me. A few questions.

>While most of my skimmer building efforts have gone into NW skimmers, I will say that the
>best performing skimmer I have ever seen was a dual recirculating beckett made by Geo run with
>a 200gph blueline pump.

kentrob11, the GEO was my #2 choice when I looked at the beckett skimmers. I ended up picking the Barr/Austin Oceans beckett skimmers (before I was drawn back to the new ER) because it was easy to clean - everything twists or snaps off and goes back together easily. But it looks to me like the GEO is a very high quality skimmer. The question I don't understand is this. Why do people say "I tried a beckett skimmer but it didn't work that well" and then when you ask them what kind it was they say either it was a no name skimmer or one they tried to build themselves. And then they compare it against a top of the line (usually) needlewheel skimmer! How is this a valid comparison? If I compare a no-name needlewheel against a GEO or Austin Oceans I wonder which one I'll end up thinking is the better kind of skimmer? For comparisons to be valid, I think you have to pick the best of breed and compare them. That's the approach I'm trying to take. There's a big difference between a well engineered needlewheel skimmer and a cheap no-name needlewheel skimmer. The same is true for becketts (maybe more true since the higher throughput probably requires better engineering to make it work up to full potential, i.e. it is a more difficult engineering problem).

On the subject of darker skimmate and pulling more out of the water, does anyone have any reference on the actual science behind this. When I used to ask this question before I always heard "Escobal covered this in his book". But it turns out this was just an assumption he made without (as far as I can tell) any research or other evidence. I understand the theory that if 10 seconds of dwell time get X amount of gunk out of your water and for 20 seconds you get X+Y out. For 100 seconds I suppose you get X+Y+Z and for 1000 seconds I suppose you could get even more (assuming even and adequate amounts of bubbles). But this all sounds like we are just guessing. It seems relatively easy to convert a beckett skimmer to a recirculating skimmer and put a very low flow pump driving the skimmer from your sump. No one seems to want to do this (MRC has recirculating beckett skimmers but they don't seem to be taking the world by storm). If slowing down the flow through the skimmer improves performance then why aren't the beckett guys all moving to recirc designs? Does anyone want to guess how much dwell time is optimal for any bubble? And what does the curve look like? Let's define the maximum organic extraction at 2 minutes, i.e. let's assume that diminished returns means we only want 2 minute dwell time because we aren't going to get much more waiting 3 minutes. Does anyone want to guess what the curve looks like? Where do you get 50% of the organics extracted? Where is the 75% point? What about the 90% point? Do you think this is a flat curve or more of a bell curve? Has anyone every seen any research that attempts to answer these questions? If not, who wants to guess?

I keep getting drawn back into the recirc skimmer argument. If Roland is right that the point of recirc skimmers is just to manage flow through the skimmer then why do we think they are better at getting out the stubborn molecules? The only thing that is going to get the organics out is a bubble. Why does a recirc skimmer have a longer bubble (not water) dwell time than a non-recirc skimmer? My old ER was the non-recirc variety and it could pull very dark and nasty stuff out of the water. You want your skimmer to produce lots of optimally sized bubbles. Too small and they won't rise. Too large and they rise too fast and don't have as much surface area as the smaller bubbles. Too much turbulence in the skimmer is bad since it will shorten the bubble life. I don't see anything in a recirc design that lengthens the bubble life. Once a bubble is created from the recirc pump it will either exit the skimmer, get sucked into the recirc input port and destroyed (and loose any organics it has collected on its surface), or burst through some other mechanism (turbulence, etc). The water hanging out in the bottom of the recirc skimmer body that does not have bubbles in it (where most of the recirc input comes from) does not really contribute to the extraction or stubborn organics. It is just sitting there waiting to be used for generating bubbles. It could just as well be sitting in the sump or in the tank. How does a recirc design contribute to increased organics extraction and if you think it does why don't the DD and beckett guys use recirc designs?

And please, does anyone have a pointer to any real research?

Al

 

[sherm71tank]

I just finished converting a diy beckett over to recirc and it works great. The foam head is more stable and so far it looks like I can also run the water level higher than before. It is being fed with a maxi-jet 1200. I had to take it out to reattach the injector but should have it running again this afternoon.

 

[alwest45]

<a href=showthread.php?s=&postid=8351881#post8351881 target=_blank>Originally posted</a> by sherm71tank
I just finished converting a diy beckett over to recirc and it works great. The foam head is more stable and so far it looks like I can also run the water level higher than before. It is being fed with a maxi-jet 1200. I had to take it out to reattach the injector but should have it running again this afternoon.

Ok, a data point. Why do you think it is better than before - why do you think the foam head is more stable? You are presumably injecting the same size and number of bubbles into your skimmer as before. So the big difference is that you are putting about 250 GPH through the skimmer instead of 800 GPH? What pump are you using to drive the beckett? Do you think it was excess turbulence before when you were trying to run the higher amount of water through the skimmer that made the foam head less stable? How did you engineer the water flow when you built the skimmer and did you take any steps to mitigate turbulence from the high flow rate? It seems to me that some of the lower end beckett skimmers out there do have a problem with higher flow and they have excess turbulence that requires you to lower the water height to keep things under control. On the other hand, my friend with the Barr/Austin Oceans skimmer runs a wet neck and doesn't have any burping or turbulence problems. I am wondering what is causing the benefit you are seeing and if my friend would see any benefit from converting to recirc? Let us know any other thoughts you have as to why you are seeing the benefits from the switch to recirc.

Al

 

[sherm71tank]

When I was running it with the beckett feeding the skimmer and the air valve wide open it would very quickly fill with bubbles and over flow even with the water level set as low as possible. With the Maxi-Jet feeding it does not do this. I can actually raise the water level higher than I ran it before. Why? I do not know but it has to have something to do with throughput. I have a Dolphin DP-2000 pump and a Resun pump slightly smaller. I think the DP-2000 is a bit much for it so will use the Resun when I get it hooked back up. The beckett flows into a u-tube directed into the riser and an atrium grate for a diffuser which reduces the turbulance and I get almost no burping if any. I put this skimmer together from parts of several other skimmers. There is no step to the collection cup it is tapered. I'll try to get some pics of it later tonight.

 

[kentrob11]

I think that a big 4-5' x 12" diameter reaction chamber dual recirculating beckett skimmer with a good pump, wetneck and a bubble diffuser would be really tough to beat by any of the top needlewheel skimmers. JMO....

 

[Roland Jacques]

<a href=showthread.php?s=&postid=8351812#post8351812 target=_blank>Originally posted</a> by alwest45

I keep getting drawn back into the recirc skimmer argument. If Roland is right that the point of recirc skimmers is just to manage flow through the skimmer then why do we think they are better at getting out the stubborn molecules? The only thing that is going to get the organics out is a bubble. Why does a recirc skimmer have a longer bubble (not water) dwell time than a non-recirc skimmer? Al

I like your questions. you put a lot of thought in them. I'm glad you pointed out you are talking about "bubble" dwell time".

To clarify my words were, recirc biggest advantage is MAINLY from controlled flow. not "just" "mainly".
Increased in air from recurculating a skimmer can be as much as 25% higher or more on some taller models skimmers. Form the lower back pressure...

 

[Roland Jacques]

Ken, i never really gave much thought to the recirc beckett. it sound like somthing worth looking at. I know H2o ENG makes them and MRC make them too. i going to look closer at those. got to go by MRC next week any way. what model did you look at?

 

[alwest45]

Roland, I hear you. But in a typical? sump & needlewheel skimmer setup the skimmer is fed by a feed pump. Those Sedras won't suck enough water from the sump to get the 1-1.5X turnover that Euroreef recommends (as 1 example). If you are feeding your needlewheel skimmer with a feed pump is there any difference in head between the circ and recirc versions? If there is, it seems like it would be a lot less than 25%?

Al

 

[kentrob11]

The recirculating beckett I saw pulled out an amazing amount of the muddiest crap I have ever seen out of a skimmer. It was run with a really high wattage pump though. The problem with it, besides the high wattage pump, was that it head to be cleaned ALL the frikin time!
With a good wetneck and a bubble diffuser to dissipate some of the turbulence, I think it would be the best performing skimmer out there. someone recommended a sequence pump at 175 watts for a dual beckett skimmer and I think that with that setup, we would have a real winner......

 

[sherm71tank]

I am currently running the RPS 2000 skimmer with an OR2700 as the feed pump. It works pretty well but nothing compared to the beckett in regular or recirc configuration. Granted though the beckett does use a bigger pump. Here is a pic of the front.

After I get it running I'll post a pic of it after 10 minutes.

 

[kentrob11]

Here's a pic of the skimmer I was talking about....

 

[sherm71tank]

Thats a monster!

 

[kentrob11]

Tell me about it. I swear the last time I saw it up and running it looked like the entire Vienna boys choir took turns sitting on it after a long night of Taco Bell and EX-LAX milkshakes.... One of these days I'm going to build one the way I think it should be built just for the heck of it....