[cali_reef]

Go with a NW skimmer like a Deltec, H&S and BK if you want a quiet and efficient skimmer. They are hard to beat for the performace and the amount of electricity used.

As for a RD on a beckett skimmer; I don't know how much pressure RD pumps puts out, the only one I have seen is the one on my BK with the needle wheel. These are low RPM pumps which means they do not put out much pressure, my RD stalls when it trys to restart after I shut it off for feeding. You need a large pressure rated pump to drive beckett skimmers in order to get the maximum performace, that means lots of power consumption, heat and noise. I sold the best performing skimmer I ever used because these issues.

[alrha]

so this means the bermuda are not becketts? what are they considered, venturi?

what are the pros/cons of beketts vs. needlewheels vs. venturi, etc?

[masterswimmer]

Quote: Originally Posted by alrha so this means the bermuda are not becketts? what are they considered, venturi? what are the pros/cons of beketts vs. needlewheels vs. venturi, etc?

No, the Bermuda's are not becketts. They are venturi.
Becketts will require a pressure rated (higher wattage ) pump.
Needlewheel just refers to the impeller on the pump. You can technically use a needlewheel as your skimmer pump for any venturi skimmer.
Venturi's can be run with a lower wattage pump. The Bermuda has a patented self cleaning venturi-mixer-injector.

R

[alrha]

Quote: Originally Posted by masterswimmer No, the Bermuda's are not becketts. They are venturi. Becketts will require a pressure rated (higher wattage ) pump. Needlewheel just refers to the impeller on the pump. You can technically use a needlewheel as your skimmer pump for any venturi skimmer. Venturi's can be run with a lower wattage pump. The Bermuda has a patented self cleaning venturi-mixer-injector. R

so i can use a needlewheel pump and it would add even more air to the venturi?
i think i need to do a little more homework on these different types of skimmers.

[regal]

Quote: Originally Posted by alrha so i can use a needlewheel pump and it would add even more air to the venturi? i think i need to do a little more homework on these different types of skimmers.

I don't think the needlewheel draws in more air. It just helps to break the air into finer bubbles to increase the efficiency of the skimmer. Venturi basically means the venturi effects created by the inlet of the pump to draw in air. So, BK, deltec and H&S etc are all needle wheel venturi skimmer.

[alrha]

with a needlewheel, the air intake is on the pump itself, no?
some skimmers (like my Tunze) have a special pump for the skimmer (that the pump sucks the air in) while others (like the Bermuda) can use any pump because the air is sucked in by the skimmer.
is there a significant difference between the 2?

[kimoyo]

Albert,

Heres a skimmer article you can look at for some info. I don't argee with everything (swirling increases contact time) but its a good reference.

All skimmers are trying to do is introduce small bubbles into the water and they do this in different ways. Air driven counter-current skimmers are tubes with air stones in them with bubbles going against the current.

Most of the popular skimmers today use the venturi effect (water going thru a smaller channel draws air in) which is just an application of Bernoulli's principle. The needlewheel, becketts, venturis all use this effect in some fashion. Becketts use the effect after the pump outlet whereas the deltecs, bks, etc. use it before the pump inlet.

Bombardment rate (# of collisions between clean air bubble bumps and drops of water) and contact time (time water is exposed to bubbles) are two things people concentrate on with skimmers. Bombardment rate - how much air the skimmer pulls in and how small the air bubbles. Recirculating skimmers try to improve contact time by recirculating the same water in the skimmer for a certain amount of time. Where becketts try to improve contact time thru longer pathways and increased velocity.

[masterswimmer]

Not all venturi's draw air through the pump. Using a needlewheel pump on a skimmer that draws air after the pump would not increase efficiency. Whereas a needlewheel pump used on a skimmer that uses the pump for the venturi would increase its efficiency. Have I confused you yet?

R

[alrha]

Thanks Paul, i'll have to read that article. i've been skimerless for 3 years, then picked up the Tunze which is just plug'n'play, so i really am not up to speed on all the different types, and dropping this much money, one wants to be sure he's getting his money's worth. the last thing i want to do is discover i got the wrong skimmer after blowing all that $$$$$$.

[cali_reef]

Quote: Originally Posted by masterswimmer Not all venturi's draw air through the pump. Using a needlewheel pump on a skimmer that draws air after the pump would not increase efficiency. Whereas a needlewheel pump used on a skimmer that uses the pump for the venturi would increase its efficiency. Have I confused you yet? R

I think you are confused

Venturi effect is based on the pressure differential(Bernoulli's principle like Paul mentioned) within the venturi device, a beckett(TM) is a form of venturi injector too and is by far the most efficient form of a air injector I have used in a skimmer.

Needle wheel pumps = no pressure = not a good pump to "push" water through a venturi device. Low rpm pump (RD) = low pressure = not a good pump to "push" water to a venturi device.

The BK, Deltec, and H&S have an air port on the intake side of the pump to suck air into the needle wheel, the needle wheel then chops up that air into tiny little air bubbles. The venturi on these skimmers are not the primary bubble making device, just a way to get air into the pump\needle wheel.