Beckett vs. Needlewheel skimmers

[JC VT]

Reskimming the water would be the best way to have the effluent as low in organics as possible, but it won't end up with the tank being lower in organics.

Randy said it better than I did.

I think if Randy's perspective is accurate and it's all about lots of small bubbles exposed to as much water as possible then the design center for many of today's skimmers is wrong or at least off target.

IMO, most skimmers are a compromise between ease of use, space, and noise. Not everybody wants to fiddle with a beckett, and not everybody has the space for one. Some that do don't want to deal with the noise. FWIW, I believe an "oversized" needlewheel would do the same: Lots of small bubbles with high throughput.

 

[hahnmeister]

Randy's perspective doesnt take into account all those other benefits of a recirculating skimmer that I mentioned earlier though. It also doesnt take into account the possibility of skimming the skimmer's intake water directly from the display tank's surface. It also doesnt take into account any possible correlations between contact time (the water's time in the skimmer) vs. dwell time (the time it takes for a bubble to rise to the surface).

I dont think that Randy knew what we here in this thread were talking about when he made that statement. I mean, point #3 from my post on the last page alone would make his statement false if his reference to 'reskimming' the water was in reference to recirculating skimmers... but its not. All he said was that it was 'reskimming'.

I think that Randy's opinion, considering our context, doesnt count.

 

[RichConley]

Alwest, this isnt a reef specific topic. Its a waste-removal topic, and has been done to death in the public sector.


Randy works in Pharmeceuticals, not industrial scale waste removal. He knows the theory well, but that doesnt mean that the application is correct.

 

[JC VT]

:lol:

His opinion counts very much, and its not just because he's Randy either. His position makes sense.

His post, IMO, was more of an indictment of the low throughput of a recirc skimmer. The same low throughput that you recommended in #3. Low throughput = more reskimmed water.

Can we agree that to keep a system clean (tank, sump), that you would want high tank turnover, a big skimmer, and wet skimming?


Also, you can accomplish pretty much the same thing as being overflow fed by setting the skimmer pick up in one compartment and the out put into the rest of the sump.

 

[JC VT]

Randy works in Pharmeceuticals, not industrial scale waste removal. He knows the theory well, but that doesnt mean that the application is correct.

Can you show where it is incorrect? Throwing a vague statement out like that seems like you're trying to discredit him, and his statement, without bringing anything to the table.

This is waste removal... for a reef tank. SPS need clean water, we know that. How do we get clean water? Waste removal

 

[hahnmeister]

Well, sure, the ideal might be to run a 6' tall recirculating skimmer with 1000gph throughput for a 180g tank... the throughput of a single-pass with the re-skimming of a recirc skimmer...

but most people just dont have that kind of space... nor the need for something that large.

As for tank turnover, no, I believe in a low flow sump, (with high flow inside the tank itself).

And as for wet skimming, I prefer dark and dry myself. Sometimes I question the need for that even (a skimmer that is), and so taking even more water out doesnt make sense to me. I let the pods and critters take care of the detritus rather than have the skimmer remove it.

 

[JC VT]

but most people just dont have that kind of space... nor the need for something that large.

Which is why I believe a Beckett would fit the bill on a reef tank that size.

As for tank turnover, no, I believe in a low flow sump, (with high flow inside the tank itself).

Why?


And as for wet skimming, I prefer dark and dry myself. Sometimes I question the need for that even (a skimmer that is), and so taking even more water out doesnt make sense to me.

Most would disagree.

I let the pods and critters take care of the detritus rather than have the skimmer remove it.

And what happens to the detritus that the critters make?

 

[big4george]

I am surprised such an expert expressing an opinion in his field of expertise is dismissed so easily and without any facts other than opinions.

 

[alwest45]

FWIW, I believe an "oversized" needlewheel would do the same: Lots of small bubbles with high throughput.

I agree. Once you understand that lots of small bubbles and high throughput is more effective then there are lots of ways to build that skimmer. And since there are more vendors building needlewheel skimmers these days you may find the best implementation in a needlewheel.

But if you think slow flow recirc skimmers are the most effective - and you know that some of the people on this thread think that in spades - then you purposefully set out to build a non-optimal skimmer. Assuming Randy is correct - and in my book his opinions count for a lot.

I also agree that you have to look at scale. Foam fractionation in a commercial waste processing plant where the daily processed waterflow is measured in tens or hundreds of thousands of gallons is very different than reef tanks (at least most reef tanks). But this may be where some of the contention comes from too. If you have a small reef tank - 100 gallons or less - then the solutions that will work best for you are probably very different than someone with a 200 or 300 gallon (or larger) reef tank even if you are trying to maintain the same kind of inhabitants. I doubt many nano reefers consider putting a beckett skimmer on their 10 gallon!

Al

 

[Roland Jacques]

The problem here is we are not all using the right words. Randy’s comments are not being dismissed by me at all. In fact he is right on target. But you have to read all the words. And not just take the part that supports an argument.

We have to look at the word Randy calls it "INTERFACE" I’ve explained it as "Air to water Ratio" or "contact time" he calls it interface much better word

<a href=showthread.php?s=&postid=8450048#post8450048 target=_blank>Originally posted</a> by Randy Holmes-Farley
Different folks may define contact time differently.


So back to contact time. Somehow one must account for how long the air/water interface is in contact with the dirty water, because increased time allows for molecules from farther and farther away to actually randomly contact the interface and bind. The binding itself is not that time dependent (at least on these time scales and perhaps excluding denaturation of proteins), but rather it is the time taken to get to the interface.

That said, my point above is that if you have a short contact time, you deplete the near interface areas of organics and do not allow time for the father away ones to reach the surface, and then you replace that bubble with a new one, you HAVE NOT reset the clock and need to wait a long time again, because the new bubble does not immediately have the near surface area depleted of organics. It can quickly start binding nearby organics right away.

This is a point that many folks seem to misunderstand, IMO. There is not a long time for the binding to take place. It is time for diffusion to take place. I agree that if it took a second or a minute or 5 minutes for the actual binding to the interface to take place, then contact time itself would be critical. Tha tmight ahppen for certain very complex proteins, but I do not believe that plays a dominating role in reef aquaria, and difussion is the key, not the reaction itself. So contact time is not important, IMO. It is the amount of air/water interface present that is actually important, and the rate at which it is turned over. Increasing dwell time may actually increase the amount of air/water interface present, depending on how it is done, but dwell or contact time itself is not a key parameter (IMO).

 

[JC VT]

Actually, I read interface to mean surface area.

 

[Roland Jacques]

yeah, I see that too, its almost used 2 different way isn't it? I did ask him to clarify this but I think it is the actual bonding contact point.

JC VT, what do you call this interaction?

"It is the amount of air/water interface present that is actually important, and the rate at which it is turned over"

 

[hahnmeister]

<a href=showthread.php?s=&postid=8451565#post8451565 target=_blank>Originally posted</a> by JC VT
but most people just dont have that kind of space... nor the need for something that large.

Which is why I believe a Beckett would fit the bill on a reef tank that size.
okay, so a person doesnt have room for a recirc that is 6' tall, but they would for a beckett that is the same? Recircs occupy a smaller area than most becketts, FWIW.
As for tank turnover, no, I believe in a low flow sump, (with high flow inside the tank itself).

Why?

Better skimming, using the surface of the tank as a natural collection area for proteins, then directly feeding this to the skimmer, making sure the skimmer has enough time to process as most it can rather than only processing 1/10 of it and spitting the rest back to the tank because the overlow is running at 1000gph, less wasted wattage...

And as for wet skimming, I prefer dark and dry myself. Sometimes I question the need for that even (a skimmer that is), and so taking even more water out doesnt make sense to me.

Most would disagree.
No, I think most would agree that I prefer darker and dryer skimmate, at least I would hope so, as I have never said otherwise.
I let the pods and critters take care of the detritus rather than have the skimmer remove it.

And what happens to the detritus that the critters make?

It feeds the corals, among other things.

 

[JC VT]

Oops. He's correct. He uses interface for the boundary between the air/water, and interface area for surface area.

 

[JC VT]

okay, so a person doesnt have room for a recirc that is 6' tall, but they would for a beckett that is the same? Recircs occupy a smaller area than most becketts, FWIW.

I never implied that a 6 ft needlewheel and 6 ft beckett are identical. I would think a 3 ft beckett would serve a 180-250g. What size needlewheel skimmer would you require to turn the tank over 5-10x an hour?

Better skimming, using the surface of the tank as a natural collection area for proteins, then directly feeding this to the skimmer

We've been over this. High flow, low flow is irrelevant to taking water from the surface.

then directly feeding this to the skimmer, making sure the skimmer has enough time to process as most it can rather than only processing 1/10 of it and spitting the rest back to the tank because the overlow is running at 1000gph

Which is why you need a skimmer big enough to handle your system.

No, I think most would agree that I prefer darker and dryer skimmate, at least I would hope so, as I have never said otherwise.

:lol: I was debating the point about needing a skimmer at all. But you already knew that.

It feeds the corals, among other things.

What type of corals?

 

[hahnmeister]

"We've been over this. High flow, low flow is irrelevant to taking water from the surface."

We have been over this? I didnt think so... and I would hardly call it irrelevant if anyone else came to this conclusion. The tank's surface water naturally accumulates more proteins and oils than the rest of the tank's water... by feeding this, throught the use of a calfo overflow, or a low-flow overflow, you target the most protein rich layers of the tank, and then direct feed them to the skimmer.

Just doing this alone just about doubled the output of my cousin's Aquamedic 5000 Baby. He had been using it fed from the return pump, but when we switched it to being fed from the overflow, the skimmate that came out was darker and more.

 

[JC VT]

Can you confirm that it was from the "calfo style" overflow or from simply being fed from the overflow.

What protein rich layer? Are there different strata where the bottom of the tank has the cleanest water and the top has the dirtiest? Or are you talking about just the air/water interface at the very top of the aquarium. Because most people have overflows (regardless of flow), that takes surface water.

It feeds the corals, among other things.

What type of corals?

 

[spazz]

<a href=showthread.php?s=&postid=8378240#post8378240 target=_blank>Originally posted</a> by NoSchwag
Here is a video of my skimmer removing solids.

Here are recent pics.

this is what your skimmate should look like. if its too light colored its not pulling enough DOC's out of the water.

 

[spazz]

just a couple more for ya. i have never see any beckett skimmer make mud before. this is less than 24 hrs of skimmate. if you cant show me a beckett that will out produce a needle wheel like this.

 

[spazz]