New Skimmer – Price is no Object!

[pjf]

Hahn's recirculating design is a bit different. The water between the two cylinders is collected, mixed with air, and pumped to the bottom of the inner cylinder. The air-water mixture is prevented by the inner cylinder from immediately returning to the needlewheel. The recirculation mechanism here simply takes the place of the airstone. Since the air is introduced at the very bottom and since the water is introduced just under the cup, there is a true counter-current flow.

In contrast, the 4-foot Turboflotor 5000 "Baby" has less than a foot of counter-current flow. The water inlet and the air inlet are very close together (http://www.aqua-medic.com/turboflotor_5000.shtml).

So we're not sure if this gravity-fed, counter-current, recirculating design can beat the sump-fed, co-current, non-recirculating BK-160 or BK-180? There must have been some serious R&D at Royal-Exclusiv?! This is when I wish the Penn State skimmer researchers would hurry up!

 

[BeanAnimal]

The only major difference between my design and that of hahns is the water inlet position. I also used an inner mixing chamber.

If you notice, some of the water entering the skimmer can directly shortcut to the output after 1 CC pass. In my design the water is forced through at least one circulation loop and up into the skimmer body, at least one time. is there a difference? I dunno.

If you observe a recirc skimmer in opperation you will notice that the bubbles along the outside circumferance of the chamber are flowing downwards. The air/water in the center of the column flows upwards and displaces watere at the top of the skimmer, where it flows back downwards (counter current).

Remember the FEED flow is much less than the recirculation flow. The recirculation flow not only takes the place of the airstones, but it moves A LOT of water.

In contrast, an airstone skimmer only moves bubbles and the water that is dragged along with those bubbles.

Both skimmers create a counter current in one form or another.

 

[pjf]

Unlike most recirculating systems, the flow in your tower is symmetric: upward flow in the center and downward flow along the sides. Your mixing box and inner cylinder isolates turbulence from the rest of the tower. The direct pump feed ensures every drop goes into the meshwheel. You've made lots of improvements. Three questions:

- Is anyone marketing a skimmer similar to yours?

- How do you size the meshwheel pump to ensure that the air-water ratio meets Escobal's 13% guideline?

- With a direct overflow feed into the meshwheel pump, does it matter if you do not purge the bubbles from the feed?

 

[BeanAnimal]

I am not sure that anybody is using the same exact concept in a retail unit. I am not even sure that I am the first person to incorporate those ideas in one skimmer. I am also not sure that it is the best overall design. It was an adaption from my CC airstone design.

The pump sizing was a guess. Larger pumps can process much more air, but also produce much more flow and turbulence.

As for the 13% several of us (TinyGiants did most of the grunt work) worked on a spreadsheet to calculate the air to water ratio in the skimmer. I have NOT calculated mine, but am rather sure that it is far below 13%. The OR3500 needlewheel is choking at between 22 and 30 SCFH of air. I should be able to get twice that into this skimmer body.

Feeding bubbles into the recirc pump should be fine. My skimmer is so tall that it must be force fed with a minijet 606 from my overflow box. I am sure that some bubbles get pushed in.

The box has created some problems that had to be overcome. The air bubbles that found their way into the box were collecting and then violently burping up through the body. I had to reconfigure the recirc pump intake to draw the water from right under the bottom plate and keep the bubbles from forming and burping.

 

[hahnmeister]

I never understood that whole 13% idea. Well, I understood IT, but I didnt think it ever held up. The ideal air throughput of a skimmer isnt based on volume, it is based on lph per body area. 22-30 scfh of air on a 6" diameter body... well... it doesnt get much better than that. 35.3/1000lph is the max for 6" diameter really. More than that, and the bubbles start to get too violent themselves.

 

[burris]

I believe the total surface area of the bubbles inside the skimmer is what is paramount. If you pumped 1000lph of air through a 6" skimmer by just sticking an air hose into it, not chopping up the bubbles, it wouldn't skim very well, would it?

 

[pjf]

<a href=showthread.php?s=&postid=10722129#post10722129 target=_blank>Originally posted</a> by BeanAnimal
The only major difference between my design and that of hahns is the water inlet position.

Your inlet placement avoids a lot of problems. You don’t have to worry about the height of your gravity feed since you’ve lowered the inlet. You don’t have to worry about turbulence at the inlet since you are directly feeding your recirculating pump. Do you need a siphon break on the drain line to the sump?

There are more differences. Hahnmeister would have to do the following to match the type of flow in Bean’s skimmer:

• Lower the inlet to the bottom
• Lower the drain to the bottom
• Reverse the recirculating pump flow
• Inject the air-water mixture into the inner cylinder
• Move the bubble plate to the top of the inner cylinder
• Close the bottom of the inner cylinder
• Drill a ring of holes in the bottom plate

Hahn’s design has counter-current flow but perhaps more turbulence at the water inlet (halo spray collar?) and at the inlet of the recirculating pump. Bean’s design eliminates turbulence in the tower.

Does anyone have predictions on their relative performance?

 

[BeanAnimal]

The skimmer is fed from the overflow via the minijet. It also returns to the overflow (on the other side of the standpipes). During a power outage the skimmer level only drop 8 inches or so.

The original plan was to feed from the overflow and return it to the sump. I was afraid of a runaway situation, even though my setup should be capable of self tuning around it.

The next plan was to feed via the input chamber of the sump (outby side of baffles) and return to the inby side of the baffles. This posed a problem with the backflow during a power outage. 15 extra gallons in the sump from the skimmer would be bad news.

So my design is mostly a product of necessity. It just turns out that it works well too!

I would not hazard a guess as to which skimmer would perform better of they both had the same body diameter and height. I would bet they would be close. The height being the important part. I would also submit that the pump itself would be a major factor. Smaller bubbles with LESS flow are the goals.

 

[BeanAnimal]

Hahn, have you looked at the spreadsheet? The 13% number is pretty hard to achive.... I don't think even the dart NW thread saw numbers above 12% or so. I could be wrong.

Have you read the Escobal explanation of the 13%?

 

[Fishbulb2]

i've read it also and made a similar spread sheet. I calculated what I would need for my RS100. No way I was going to get that much air into it. I wanted to buy a luft pump to pump that much air into the skimmer. There's no way that would have worked without the pump cavitating.

 

[BeanAnimal]

I purchased the Escobal book used for a hefty price. I can not find it for the life of me. The warden likes to collect things around the house that she thinks are no longer needed. I suspect it went the way of my green suede Vision skate shoes and the others things she has deemed clutter and irrelevant. I suppose one day it will be me that gets tossed....

 

[pjf]

Re: The Quote Game

Re: The Quote Game

<a href=showthread.php?s=&postid=10721239#post10721239 target=_blank>Originally posted</a> by BeanAnimal
You did say that price was not an object. I think that you can get one hell of a nice BK skimmer to fit in your stand that will almost certainly outperform a scaled down version of the hahnmeisters design (which is meant to be tall and calm).

OK. We can come back to the ideal DIY skimmer.

Which retail skimmer is best for a 100-gallon system with a 30-inch cabinet stand (28" interior)? You say Bubble King (Mini?). Hahn says ATB cone (small or nano). They don't look like anything P. R. Escobal would design. They seem "out of the box."

The test results aren't in but what are their design strengths and weaknesses?

 

[BeanAnimal]

I have heard very good things about the BK skimmers, even though the price is very high. I have also heard good things about the ATB. Folks love their ERs etc.

I would be apt to say that they are not ideal skimmers compared to a similar design that is scaled to a 4', 6', 10' or whatever height.

When you can only consider what will fit within your space and budget constraints. Thay may mean running carbon to remove the yellowing compounds.

Don't get me wrong, I understand your desire to test and to have every skimmer down the pike ranked by that meaningful test. The same can be said about Tires, Amplifiers, Refrigerators, Beer, or anything else that is subject to varied environments, tastes, etc.

This is where informed opinion and observation help us wade through the options. Sometimes were get lucky and ward off buyers remorse for another purchase on another day

 

[JCTewks]

IMO, you will get better performance, and better ovarallDOC removal (esp more of the moresoluble DOC's) with a well designed very tall skimmer.
If you are only going to be feeding 75gph theough the skimmer, i don't think you'll see much in the way of added turbulence. Personally, I would build a skimmer similiar to either bean or hahn, but throw a wet neck on it and do 100% of your feed water down the wetneck. Every drop of feed water would have to fight it's way through everybubble ion the skimmer to reach the output.

As to the co-current vs counter-current...I remmber reading in bill wann's old tank thread that he switched to a top feed from a bottom feed and the skimmer performance went up considerably. There was more turbulence in the body, but it was on a 1500gal tank. Bill said that the added turbulence was woth it for the greater improvement of the skimmer.

But, really, you're only putting 75gph through it...just run it in through a wetneck...plus you get the bonus of the original purpose of a wetneck...a clean neck

 

[pjf]

Wetneck Inlet

Wetneck Inlet

That is a good idea! For a small system with 75 gph of flow, the inlet may just as well be the wetneck.

Where does one get exotic skimmer parts, such as:

• Halo inlet spray collars
• Wet-neck inlets
• Zero-clearance collection cups
• Tapered neck flanges
• Pipe connectors for cylindrical walls
• Eheim or Sicce pumps with thread or needle wheels?

The wet-neck or "halo" spray collar will help with symmetric flow at the inlet. The zero-clearance collection cup will gain a few inches of reaction height.

If you have links to detailed wetneck designs, that will be great!

 

[BeanAnimal]

DIY PARTS:
• Halo inlet spray collars
• Wet-neck inlets
• Zero-clearance collection cups
• Tapered neck flanges

Aquaticecosystems:
• Pipe connectors for cylindrical walls

Most online vendors: The threadwheel is DIY
• Eheim or Sicce pumps with thread or needle wheels?

I built a prototype magnetic collection cup using neo magnets embedded in the flanges. It worked very well, but in the end I went with the DIY twistlock flange.

 

[BeanAnimal]

A trip to the DIY forum will be of great benefit in your quest for skimmer fabrication.

 

[JCTewks]

man...i just spent 20 minutes typing a response with links and everything...then it dissapeared don't need to type it all again as beans links were spot on other than I think the Sicce pups can only be found at protein-skimmer.com and they have a DIY threadwheel kit too.

an Eheim 1260 would do the job, and the stock Impeller can be modded into a threadwheel.

you'll need to force feed the pump if it has more than 30" of head on it anyway...so a billion dollar pump may not be needed. I can do a threadwheel for you if you buy the pump...no charge...I just love DIY

 

[JCTewks]

the zero clearance collection cup can be done with a union for a neck as small as your will be...3" i'm guessing?

 

[BeanAnimal]

I saw some BIG 4" and 6" pvc unions on eBay not long ago. They were only ~$40 each... that is a great deal.


JC: Get in the habbit of copying the reply text before you submit. You used to be able to click refresh and the form data would repost. Now it does not... but the browsers back button may work in some cases. Frustrating to say the least.