Short&Fat vs Tall&Skinny Discussion.

[SeanCallan]

I want to hear everyone's view points.

Whats the real difference? Any advantages?

[ldrhawke]

With all the BK rah rah I'll bet I know the consensus. Short are often easier to fit into a reef tank system, but tall which have been used for years in commerical applications are considered more efficient by many.

[SeanCallan]

Why though? What is the advantage to the short fat body style?

I know the taller the longer the bubbles have contact with the water, the better.

[mikester]

Most recirculating skimmers are short and fat because if they are too tall, the recirculating pump has to push harder against the head pressure from the tall column of water. With a taller body, you lose efficiency because of that head pressure, so you either have to use a bigger pump (more power consumption) or settle for less air injection.

For example, look at the Deltec 702 vs. 902. The only difference is that the 902 is about a foot taller - they have the same diameter and the same pumps. But the 902 injects 200 lph less of air (1600 lph vs. 1800 lph) because of the extra pressure from the taller reaction chamber. Deltec rates the 902 to handle an extra 100 gallons, so they must feel that the tradeoff in air injection is offset by the increased contact time from the extra height.

[SeanCallan]

Yeah, I was actually looking at the deltecs.

I also heard shorter skimmers are more expensive due to the wide body.

[moonpod]

It's about volume. You get more volume bang for your buck with less head pressure in a wider skimmer (it's the radius squared thing), but a "big" skimmer is better than a "small" skimmer regardless of which way you get the size (height vs width). Commercial units are big, b/c they are big period. There also are practical considerations (ie width of the tube) in terms of what you can find that is reasonably priced. Wide acrylic tubes are much more expensive b/c the surface area and hence the amount of material is much more. So in the end, it's a silly arguement. It's about the volume. You can get that volume whichever way you want. Just remember that it'll increase faster with diameter, BUT you have practical considerations in terms of what diameter tubes you really have available to you. ldrhawke's modded unit is great, but I bet you it'd be even better if it was wider (assuming you use "enough" pump).

[ldrhawke]

It's about volume. You get more volume bang for your buck with less head pressure in a wider skimmer (it's the radius squared thing), but a "big" skimmer is better than a "small" skimmer regardless of which way you get the size (height vs width). Commercial units are big, b/c they are big period. There also are practical considerations (ie width of the tube) in terms of what you can find that is reasonably priced. Wide acrylic tubes are much more expensive b/c the surface area and hence the amount of material is much more. So in the end, it's a silly arguement. It's about the volume. You can get that volume whichever way you want. Just remember that it'll increase faster with diameter, BUT you have practical considerations in terms of what diameter tubes you really have available to you. ldrhawke's modded unit is great, but I bet you it'd be even better if it was wider (assuming you use "enough" pump).

Sorry MoonPod we disagree totally on volume is the only thing and shorter is better. Taller allows for a longer contact time because of a longer bubble rise contact time. The more contact time the better in a skimmer.

Also your analysis on pressure head doesn't take into account the counter head from the suction head. If you make a system head curve you will see that the head pressure against any pump is also most totally from friction head becasue of suction head is the same as the discharge head. No more power is required from a pump on a 24" high skimmer than is required on a 24 foot higher skimmer or a 240 foot high skimmer for that matter, other than friction loss in the lines. You have the same static pressure on the suction and discharge side of the pump in a recirculating skimmer.

It is true though that you will need a larger pump to develop higher flow rates and more pressure to over come the added static head the ejector sees, which allows it to pull in the same or more air.

[John Brancheau]

Just my take from personal experience, I have run a Euro 8-3 and Euro 8-1 side by side for about a year now, the only difference in these two skimmers is the height, I think about 10 inches of chamber is all that seperates these two, I can tell you this, while they are both great skimmers, the 8-1 kicked the 8-3"s butt, better foam and skimmate funk...

Does this mean shorter is better, not positive, but I can tell you for sure, the shorter skimmer of the exact same dimensions worked better for me.......

[moonpod]

John some of that again is related to having "enough" pump to power the volume. The 8-3 was taller, but did you have enough "oomph" to make that volume "work" or not. ldrhawke will always advocate toothpick skimmers and I will always say it's about the combo of volume (however you want to get it) and "enough" pump.

[John Brancheau]

Moonpod,

You are probably correct, I do not think that the 8-3 had enough 'oomph", but we will see, the guy getting my 8-3 will be adding a re-circ to it , we will see then if it makes enough difference, personally I think Jeff shuld have sold that skimmer with a 9000, not 5000....

[Ger]

My opinion, the taller the better...however, the pump will need to be able to handle the head pressure. If not, it's counter productive. I think the trend has been shorter skimmers because they became more efficient and you didn't need a tall column anymore to get the same or better results. I wouldn't be surprised if we'd start to see tall skimmers some time soon again....with stronger and more efficient pumps.

[nyfireman3097]

what makes a skimmer better then another one ?
Nick

[Fins Reef]

What makes one skimmer better than the other goes into many points.
In order for a skimmer to be effecient it needs to have the right combination of air intake, the bubble size, the height, the width, and the water throughput. That combination is the research and development that has been put into your better skimmers. As Mikester said the current needlewheel pumps on the market decrease air intake as height increase, but sometimes the contact time makes up for the less air. One reason I believe you see shorter skimmers is to try to fit in the standard US tank stand. Everyone does not have a pump room/basement to set a skimmer up in. The most of US customers want a package that can be tucked away under the standard 30" tall stand. JohnB is right about the 8-1 outperforming the 8-3 IMO that is due to the increase air bombardment rate you get in that size package, for the 8-3 to utilize its full height, the pump needed to be upsized. That is one example of the total package yields the best results. I find that some companies have put much development to find the right combination of pump/skimmer size and when you run those skimmers you can tell the difference by a large margin. That is what BubbleKing,H&S, Deltec, and Grotech have over most other skimmers.

[Fins Reef]

By the way,
I am a Short, Fat Guy, but for some reason my life loves me anyway

[nyfireman3097]

lol so if i put a BK needlewheel and a BK pump on my turboflotor 1000 will it work better ?
Nick