Who rates skimmers

[sphelps]

Originally Posted by Mr OM

That wasn't what I asked, so I will rephrase, if I throttle back a Dart to 3000 gph and make the outputs disperse similar to a tunze or vortech would they be similar?

Yes and no, same flow rate different velocity. The lower velocity and greater spread creates an advantage as simulates natural water movement better.

[mr.wilson]

Originally Posted by sphelps

Tunzes and Vortecs push flow outwards in an expanding direction, this results in a larger area and therefore a lower velocity. Velocity is not that same as flow rate.

It also results in detritus being pushed down into the substrate rather than up to the surface for suspension, surface skimming and gas exchange.

If you like the outward flow of a Vortech, it can be easily replicated on a closed loop with a penductor, or a series of them if you split your closed loop into several ports.

[littlesilvermax]

Originally Posted by Mr OM

We are not really talking apples to apples here, both vortech and tunze claim flow numbers that becomes converted to gallons per hour of flow.
I would not argue their claims in the slightest, but just for a second could you answer me one simple question, if a vortech or tunze produce 3000- gph of flow , and you throttle back a dart to produce 3000 gph would the result be the same?

I know what you are saying, and totally agree.

3000 gph from a dart will INDUCE a lot more flow then that in the tank. it is hard to compare that with a tunze or similar powerhead.

[mr.wilson]

Thanks for posting that article, Dana Riddle is an excellent source. It's good to see hard numbers and it's a shame that manufacturers won't spend the resources to achieve this themselves.

As I stated before, Vortechs work around most of the potential problems that arise from powerhead applications. I still argue that they have the following drawbacks...

1) Only suitable to be located at opposing ends of the tank. They cannot be located on the front, or easily on the back, or on the bottom, or within the reef structure, as closed loops can.
2) They are not directional, meaning they are limited to pointing forward (not up or down or at any other angle).
3) They cannot be easily disguised inside or outside of the tank.
4) They require a network of wires running around the outside of the tank.
5) They are slightly louder than a closed loop pump. CL pumps can be remote, while Vortechs must be on the side of the tank.
6) They give off more heat transfer directly to the tank wall (some acrylic tanks have had stress crack issues. According to Riddle, the external temperature is 138F.
7) They cause vibration within the tank which can disturb livestock.
8) Circular or laminar flow is not possible with Vortechs. Water travels in one direction from end to end hitting the opposing wall or opposing flow. I read the velocity numbers, but I don't have pressure pump values to compare them with.
9) I don't know how often Vortechs need to be serviced, but CL pumps have at least 10 years before the volute needs to be looked at. Calcification only occurs on metallic pumps, so magnet coupled pressure pumps don't need to be soaked in acid. Vortechs have not been on the market long enough to establish longevity.
10) There's always a #10. Vortechs are hard to use with tanks that have cabinetry that covers end walls or aquariums fit into walls where access is limited.

The extra 100 watts used by a closed loop pump (if that is truly the case) would not be 100% heat generation, and even if it was, it wouldn't impact the cooling system of a house. These days most people open windows before they turn on the A/C. I'm not about to argue that it contributes to heating your home in winter either

In my opinion, the flow from a closed loop pump has more flexibility to be used for better flow dynamics than a Vortech system. By no means does this make a closed loop system a license to use poor flow placement, nor does it exclude Vortechs from fulfilling some of the flow requirements of a tank.

If optimum flow dynamics are in place, which is more readily achievable with a closed loop system, a 15x turnover ratio can be just as effective as a 40x turnover ratio. It is arguable, that 3600 GPH with a closed loop is worth 4800 GPH from a well configured Vortech system.

If you aren't particular about aesthetics or flow dynamics, then Vortechs will work well for you. If you feel you can recoup the initial cost of a series of Vortechs with energy savings, then it has further added value.

[sphelps]

Vortecs have the advantage of the external motor which of course presents limitations however hobbyists have the choice to use them when appropriate and could also use Tunzes which solve many of these limitations.

1) Only suitable to be located at opposing ends of the tank. They cannot be located on the front, or easily on the back, or on the bottom, or within the reef structure, as closed loops can.

They can be located virtually anywhere, including within the reef structure. Maybe not as desirable in some locations but they also have the advantage of relocation if aquascaping or flow demands change, not as easy with closed loops. These pumps also have the advantage to pulse at critical frequencies to produce a natural wave type movement. Corals do not benefit from direct flow so I don't even see the advantage of pointing flow directly at the reef structure.

2) They are not directional, meaning they are limited to pointing forward (not up or down or at any other angle).

Tunzes are certainly directional, the new models have movement in almost all directions.
"they offer a lot of flexibility with respect to positioning and orientation of the water stream, which can be adjusted in such a way that an effective flow is produced over a long distance in the aquarium at lower power consumption."

3) They cannot be easily disguised inside or outside of the tank.

4) They require a network of wires running around the outside of the tank.

Cables can be tied back to one location like the back of the tank, or if all sides are viewable through the overflow.

5) They are slightly louder than a closed loop pump. CL pumps can be remote, while Vortechs must be on the side of the tank.

The further remote the more friction loss and most don't like to run large PVC pipe through their house. Vortecs are virtually silent if balanced correctly, and you can't even hear a Tunze running. CL pumps like a Dart are very noisy in comparison.

6) They give off more heat transfer directly to the tank wall (some acrylic tanks have had stress crack issues. According to Riddle, the external temperature is 138F.

Splitting hairs, heat will transfer from the motor to the water moving through an external pump in a similar fashion. The housings on the dart pumps I owned were warm to the touch and I've seen similar pumps fail when flow valves were shut and forgotten about. The pump is air cooled but still relies on the flowing water to remove part of the heat produced.

7) They cause vibration within the tank which can disturb livestock.

Interesting theory but I asked my fish this morning, they don't mind it. Pumps can also be turned down over night with controllers and create a more calming environment.

8) Circular or laminar flow is not possible with Vortechs. Water travels in one direction from end to end hitting the opposing wall or opposing flow. I read the velocity numbers, but I don't have pressure pump values to compare them with.

Turbulent flow could be a good thing as it would create a more random flow pattern adding to the snow globe effect. However you may have it backwards, a Tunze or Vortec spreads flow out over a larger area creating lower velocity which would promote a more laminar environment, closed loops often use jets which create high velocity patterns which disturb the water around it creating a turbulent boundary layer.

9) I don't know how often Vortechs need to be serviced, but CL pumps have at least 10 years before the volute needs to be looked at. Calcification only occurs on metallic pumps, so magnet coupled pressure pumps don't need to be soaked in acid. Vortechs have not been on the market long enough to establish longevity.

Completely false, external pumps, shaft driven, or magnetically driven, require frequent maintenance. Magnetically driven pumps require impeller and shaft cleaning as often as any power head. Shaft driven pumps also require frequent cleaning to prevent seal failure and build up which creates both resistance and noise. When I had issues with my reeflo dart the manufacturer stated the the impeller housing must be flushed and cleaned every three months to prevent seal failure. The seal also should be constantly checked for salt creep for the same reason.

10) There's always a #10. Vortechs are hard to use with tanks that have cabinetry that covers end walls or aquariums fit into walls where access is limited.

So a closed loop is easy to access with limited cabinetry access? I can't see how in most aquariums a closed loop offers easier access than power heads like tunze and vortec.


In my mind quality power heads like Tunze and Vortec offer the following advantages over CLs.

1) Easier setup and maintenance
2) Better resale and easier to incorporate in new tanks. Plumbing for a closed loop is expensive, I did a 4W OM on a clients tank and it cost around $400, very rarely can plumbing parts transfer to a new tank.
3) Can be relocated at anytime with minimal effort
4) Can be upgraded or down graded without major modifications to the tank
5) Use less power, greater efficiency a dart runs 22.5 GPH/W while a Tunze Stream 6000 runs 123.2 GPH/W
6) Create less noise, sorry but a tunze is quieter than a dart
7) Much better flow control and have better capability to produce more natural wave flow. The vast selection of electronic controllers is far superior to the OM and SCWD devices which are only ones I'm aware of.
8) Simplicity, closed loop systems require more experience in plumbing. You also can't really contain both a closed loop system and a sump system in one stand, it would have to oversized or very tight making maintenance a nightmare.
9) No tank modifications needed, Closed loops require a swiss cheese tank to hide the plumbing
10) Better reliability all the way round. The external plumbing required for a closed loop can be a dangerous game, bulkheads can leak down the road and replacement would be a tremendous headache requiring the complete dismantle of an established aquarium. People worry enough about the actual tank seams leaking, why add more potential for leaks?

I could go on but 10 seems to be the magic number.

[mr.wilson]

I was responding to the comments that Canadian had made about Vortechs. Vortechs are easily the best powerhead on the market, if you can still call them a powerhead, more of a magnet spinner. They address most of the problems that submersible pumps cause. If I was talking about Tunze pumps I would have address different issues.

The only reference I have of sound was from the Dana Riddle article where he claimed they have a whine which increase in frequency as they power up and down. I've seen them is use on tanks, but only in fish rooms or noisy hobbyist tanks.

Tunze powerheads can be located anywhere, but they need to be removed for periodic servicing and they have moving parts in the reef. I don't agree that magnet coupled chemical pumps with sealed bearings such as Iwaki require preventative maintenance or volute cleaning. It appears that you experience is limited to non-chemical pool pumps like the Sequence line, so I understand why you don't like closed loop systems. This line of thought is equally as unfair as me comparing a Vertech pump to a maxijet, which I have not done.

I'll admit some of the issues I have listed are not significant drawbacks, like extra power cords, but it was a simple comparison of pros and cons just as I would accept that Dart pump is too loud for a home aquarium and it isn't suitable for marine applications.

I agree heat transfer comparisons are splitting hairs. I was just using Dana Riddles comments about heat in comparison to Canadian's claims of added air conditioning costs to counter the heat thrown from a closed loop pump. They both have external temperatures of 130F, it's just closed loop pumps use heat sinks and fans to mask the heat. You could easily put a fan on a Vortech if it was ever an issue, and I doubt it would.

I don't have the time or desire to look up articles about vibration or moving parts in reef aquariums. They may or may not affect the physiology of fish and invertebrates, but it remains as something to consider when weighing options. Your claim that you can tell it doesn't effect your fish is silly.

Turbulent flow doers not create random flow patterns. They may be more intricate, but they are not random unless you have programmed sporadic sequences into your powerhead controller.

You have to make up your mind about the flow you are endorsing. One minute you are talking about prop powerheads offering lower velocity and fanned out, diffused flow as being beneficial, and in the next paragraph you are saying a closed loop pump has too much velocity so it moves too much water as it passes through the tank. If it moves more water than the amount measured leaving the effluent port, then let's add that to the total flow rate as we should.

My point about pump access with a closed loop was you unplug the pump and shut off two union valves and you can remove it to service, upsize or downsize. With Powerheads you may have to move corals if you have them within the rock work. Vortechs are easy to access because they don't work in these locations and don't utilize suction cups or plastic clips.

In my mind quality power heads like Tunze and Vortec offer the following advantages over CLs.

1) Easier setup and maintenance

Easier set-up, harder maintenance. Closed loop owners forget they are even there, while powerheads are part of routine servicing.

2) Better resale and easier to incorporate in new tanks. Plumbing for a closed loop is expensive, I did a 4W OM on a clients tank and it cost around $400, very rarely can plumbing parts transfer to a new tank.

I don't know which would have a better residual value, but it's a strange benefit to consider. For that reason, I'll give you the point.

3) Can be relocated at anytime with minimal effort

Absolutely, but you will never get it where it works best.

4) Can be upgraded or down graded without major modifications to the tank

Just as a closed loop pump can. A 1" in and out port will fit hundreds of pump possibilities. Once again, planning for re-engineering is a poor selling point.

5) Use less power, greater efficiency a dart runs 22.5 GPH/W while a Tunze Stream 6000 runs 123.2 GPH/W

This is only true if you are measuring strictly the water exiting the effluent port and not the overall effect. The trade off with high volume low energy consumption pumps is velocity. There are arguments for both high and low velocity systems. Closed loop systems can simultaneously offer both with a wave making device, while powerheads are limited to low velocity, lower velocity, and no velocity. Energy savings are nominal. While they may be 50% in the best of scenarios, the hard number is $5-10 a month. In a society where we drive cars that get 20MPG while 60MPG cars are readily available, it's a hard sale. How often do you fill up your BMW gas tank? Whatever you are spending, it's three times higher than what it could be.

6) Create less noise, sorry but a tunze is quieter than a dart

Once again if you are going to compare to a Dart then I will use an oil cooled cast iron sump pump as a basis for powerhead comparisons An Iwaki or Panworld 70 located in a remote location away from the cabinet will not be audible at all. Alternatively a Red Dragon, Deltec or Poseidon pump is also inaudible.

7) Much better flow control and have better capability to produce more natural wave flow. The vast selection of electronic controllers is far superior to the OM and SCWD devices which are only ones I'm aware of.

Then you have proven once again that your knowledge is limited.

8) Simplicity, closed loop systems require more experience in plumbing.

Absolutely, just as proper Tunze Stream placement requires more experience than putting them in the corner where they look good.

9) No tank modifications needed, Closed loops require a swiss cheese tank to hide the plumbing

There is no reason why a closed loop system with an external pump requires and holes in the tank. If you can live with powerheads in the tank and hanging off of the side, then a few pipes running over the trim at the back should not be a problem.

10) Better reliability all the way round. The external plumbing required for a closed loop can be a dangerous game, bulkheads can leak down the road and replacement would be a tremendous headache requiring the complete dismantle of an established aquarium. People worry enough about the actual tank seams leaking, why add more potential for leaks?

First of all, I was right, there is always a #10. You are absolutely correct, a tank full of extra valves, fittings and bulkheads is a liability, especially if it is not done properly. It's a very small liability, but it still exists. A closed loop system with external plumbing running over the trim saves the cost of extra holes, bulkheads and valves. I see a need for only two drain holes with anything else being a luxury. Doesn't your tank have four holes in the bottom? This adds the extra cost of tempering and or a thicker bottom panel. The bottom is the easiest panel to get a leak with as there is more hydrostatic pressure on it and long pipes can bend and cause water to leak past the bulkhead flange.

I could go on but 10 seems to be the magic number.

At least we agree on something

[sphelps]

Well we could go on forever, I still obviously don't agree with all your points and you obviously don't agree on mine. We can always find something pick at and spin against one another so before this gets out of hand again I'm agreeing that closed loops are a good option if done correctly and the space is available. However I personally prefer the use of certain power heads for the reasons stated and not because of my lack of experience or knowledge of closed loops.

I would have been better to have this discussion with a broader audience, I find threads like this quickly die on this site and you end up in this exact position

Not that this would particularly prove anything but I think it would be interesting to setup a poll or two to see what other hobbyists find and believe works before for water flow.