Is there a way to make a return act like a Vortech?

[Anonymous]

Still thinking about my future tank here.

So, now I was wondering what return would make sense in a low speed, soft and broad flow tank. And I was thinking that the flow from a return pump might be rather narrow and hard for the sort of tank I have in mind (for corals that prefer less turbulent and violent flow than SPS - e.g. LPS like Alveopora, Euphyllia, Acans, Blastos etc).

I know there is a device you can fix to a return pipe to increase the flow (eductor?), but is there a way to broaden out the flow and soften it instead? Or do I simply have to go for a lower-powered return pump? And if that's the case, what sort of pump would work best in a 36" long x 24" deep x 18" high?

Oh, and it looks like my idea of having two MP10s for this job may not be so great. The Vortech website says that they're able to be used on tanks of up to 3/8" glass thickness (which my calculations tell me is 0.95cm). I will probably be looking at glass thickness of 1cm. I wonder if that small difference makes this impossible. :?

 

[Ben1]

Yeah I originally did eductors on my new tank but the back pressure they caused made my plumbing leak. I oversized my return pump thinking I could handle the flow, which I can if I enjoy looking at lots of bubbles. MY sump has 3 baffles but if I turn the return pump up even past 3/4 full I get tons of mini bubbles in the display. This may be a reason not to go to big with the return. In anycase I don't think you would have gotten the flow you expected from the mp10's and upgraded in the future anyhow. I would still go with an mp40w if I was you and call it a day. I know you are thinking softies now :roll: but you can set the vortech to pulse or run in one of its other modes and it wont be full all the time. I think you'd be best just going with the 40, or a couple maxijet mods with magnets. I can't stand seeing cords in a tank though so the vortech would look better but the maxis would be cheaper.

 

[Anonymous]

Maybe I'm misunderstanding or the title was misleading. It's not so much the power of a MP40 I'm after, but the breadth and softness of the flow of a propeller-driven powerhead (the Tunze Streams are of course the same). The eductor example was just an example of an attachment you could put on an return pipe - I'm not after the same increase in flow strength. Unless I'm misunderstanding how eductors work, I thought that they simply concentrated the flow to make it higher pressure and faster (kind of like a finger on the faucet will make for a high pressure stream of water). Not what I'm after.

Are you saying that, even in a tank of LPS and softies, the MP40 would be a good choice? Strikes me that it would have far too much flow. I know that the orthodoxy nowadays is to have as much flow as possible, but I can't think it's a good idea for the sort of coral I want to get. Which is why I was talking about 2 x MP10s.

 

[Anonymous]

I'm going to vote note, simply put you have a pressurized stream (your return pump) and you want it to act like a diffuse flow, it's not going to happen. If you look at the propeller on a vortech (or any of those diffuse pumps) they're like a propeller in that they push water. On most returns you'll see they're either flat or curved notches that are all parallel to a surface, basically they work via centrifugal means to move water.

Now I suppose it MIGHT be possible if your outlet tapers open slowly and perhaps put some diffusion barriers in there... but I can't see how that could be practical.

 

[Len]

If you split the effluent enough times, it'll soften the flow. But it'll also kill a lot of the flow with all the turns. There's no efficient way to make a high pressure pump act like a prop pump afaik.

 

[Anonymous]

OK guys, thanks for the replies. That's what I suspected, but wanted to check I wasn't missing something obvious.

The only other option I guess might be something like this. It's an optional extra from the place I'm likely to end up getting my aquarium from. What do you think?

 

[Lars]

What if you increased the diameter at the outlet and affixed a propeller to that opening? The flow would spin the propeller and diffuse the pattern much like the power heads that use the propeller as the mechanism to create the flow. how about that?

 

[Len]

All these methods should work to make the flow much less high pressure, but both are going to reduce the total amount of flow significantly. It's not hard to diffuse the flow ... it's just hard to do it without wasting a lot of flow in the process

A prop pump is the easy and most efficient way to have high flow and low velocity. My mod'ed MJ1200 prop pump in my LR curing tank (costs me a whole $30 ) puts out amazing flow ... but I hear they tend to break down.

 

[Anonymous]

Maybe I could live with a loss in flow, if it achieved what I wanted (the broad flow I'm talking about). As I've said, high turnover is not necessarily my central objective (given the corals I want to keep).

What are your thoughts on the spray bar Len? My main concern is that it will lead to a very strong jet of water from the hole nearest the sump and a piddling flow from the furthest hole.

Or on Lars' propellor idea? My main concern with that is that my DIY skills will not be up to it and that it might be rather unsightly...

 

[Len]

No idea about the prop idea, but that sounds novel. If it works, it would be a popular item

Spray bars work fine if it's sealed. The pressure creates a fairy uniform flow from all holes. The problem I've had is the holes clog. Don't drill them too small.

 

[Anonymous]

All these methods should work to make the flow much less high pressure, but both are going to reduce the total amount of flow significantly. It's not hard to diffuse the flow ... it's just hard to do it without wasting a lot of flow in the process

Incorrect there Len (were you baiting me?)

Increasing the diameter of the pipe actually will increase the total flow of the pump. This is because the larger the pipe the slower the water will flow, the slower the water flows the less losses. It looks less because the velosity of the water will be slower.

IMO the best way to difuse the water is to up size the pipe right after the outlet of the pump. You should still strive to keep elbows and tees to a minimum. With slowing the water down the effects of them will be less than trying to pass the same flow through a smaller pipe.

If you doubble the pipe diameter the velosity decreases by a factor of 4 because it is a function of area (d^2)

The problem I see is if you increase the pipe to much you get next to no velosity and no mixing in the tank.

 

[Len]

All these methods should work to make the flow much less high pressure, but both are going to reduce the total amount of flow significantly. It's not hard to diffuse the flow ... it's just hard to do it without wasting a lot of flow in the process

Incorrect there Len (were you baiting me?)

Increasing the diameter of the pipe actually will increase the total flow of the pump. This is because the larger the pipe the slower the water will flow, the slower the water flows the less losses. It looks less because the velosity of the water will be slower.

IMO the best way to difuse the water is to up size the pipe right after the outlet of the pump. You should still strive to keep elbows and tees to a minimum. With slowing the water down the effects of them will be less than trying to pass the same flow through a smaller pipe.

If you doubble the pipe diameter the velosity decreases by a factor of 4 because it is a function of area (d^2)

The problem I see is if you increase the pipe to much you get next to no velosity and no mixing in the tank.

Hehe.
If you open up the piping (e.g. from 1" to 2") at the nozzle, it's not going to do all that much.
If you run nothing but 2" pipe all the way up, it could help, but it could also hurt, depending on how high you plan to pump. There's an inflection point. I know it's harder to get a Iwaki 30RLXT to pump 10 vertical feet with a 1 1/2" diameter pipe then a 1" diameter pipe. Increasing the diameter decreases velocity for sure, but you have to take into account how the pump handles head pressure too. As you said, you can eventually increase the pipe wide enough (again, depending on head) where you get no velocity. No velocity means zero efficiency

I still say there's no easy way to get slower flow with high pressure vertical pumps without adversely effecting the total turnover rate.

 

[Anonymous]

All these methods should work to make the flow much less high pressure, but both are going to reduce the total amount of flow significantly. It's not hard to diffuse the flow ... it's just hard to do it without wasting a lot of flow in the process

Incorrect there Len (were you baiting me?)

Increasing the diameter of the pipe actually will increase the total flow of the pump. This is because the larger the pipe the slower the water will flow, the slower the water flows the less losses. It looks less because the velosity of the water will be slower.

IMO the best way to difuse the water is to up size the pipe right after the outlet of the pump. You should still strive to keep elbows and tees to a minimum. With slowing the water down the effects of them will be less than trying to pass the same flow through a smaller pipe.

If you doubble the pipe diameter the velosity decreases by a factor of 4 because it is a function of area (d^2)

The problem I see is if you increase the pipe to much you get next to no velosity and no mixing in the tank.

Hehe.
If you open up the piping (e.g. from 1" to 2") at the nozzle, it's not going to do all that much.
If you run nothing but 2" pipe all the way up, it could help, but it could also hurt, depending on how high you plan to pump. There's an inflection point. I know it's harder to get a Iwaki 30RLXT to pump 10 vertical feet with a 1 1/2" diameter pipe then a 1" diameter pipe. Increasing the diameter decreases velocity for sure, but you have to take into account how the pump handles head pressure too. As you said, you can eventually increase the pipe wide enough (again, depending on head) where you get no velocity. No velocity means zero efficiency

I still say there's no easy way to get slower flow with high pressure vertical pumps without adversely effecting the total turnover rate.

Actually incorrect again. It is a visual trick.

What you are observing is the decrease in velosity. Pumps don't pump speed, they pump volume. You will never get to a point where there is no veolsity, no matter how big you make the piping. Unless you turn the pump off.

The pressure at the bottom of a column of water is the same no matter how wide the colum. The pump will not care if the 10 ft tall column is 2", 2' or 200' in diameter.

Opening up at the end will do little to spread the flow.

 

[Len]

But explain this. I can get my Iwaki 30RLXT to pump over 12 feet via 1" tubing. Using 1 1/2" tubing, the water never gets there (ie, no velocity).

 

[Anonymous]

But explain this. I can get my Iwaki 30RLXT to pump over 12 feet via 1" tubing. Using 1 1/2" tubing, the water never gets there (ie, no velocity).

Without knowing the details I can not answer. If it is pumping to 12 ft in 1" tubing it should pump the same height in 1 1/2" tubing. How long did you let it run? 1.5" dia tubing is 2.25x larger in cross section area. It is going to take 2.25x longer just to fill the line full.

 

[Len]

I admittedly didn't let it run super long (wasn't a continuous application), but all I know is when i switched to 1", it worked right away.

Here's how I theorized it: You have a pump that moves 1000gph rated through it's 1" in and out. If you use 2" tubing, you'll still be moving 1000gph, but over 4x the cross diameter. This means lower velocity, but I think it also means a lot less maximum vertical height (i doubt it's loss of a factor of 4 though). When you're running horizontal, this isn't an issue.

 

[Anonymous]

I admittedly didn't let it run super long (wasn't a continuous application), but all I know is when i switched to 1", it worked right away.

Here's how I theorized it: You have a pump that moves 1000gph rated through it's 1" in and out. If you use 2" tubing, you'll still be moving 1000gph, but over 4x the cross diameter. This means lower velocity, but I think it also means a lot less maximum vertical height (i doubt it's loss of a factor of 4 though). When you're running horizontal, this isn't an issue.

Nope. It is pumps and fluids 101.

1. Pressure in a column of water is the same at a give depth regardless of cross section.
2. A pump's output (volumetric flow rate) is goverened by back pressure at the nozzel which is the height the water is pumped+ losses due to flow velosity+difference in pressure at the inlet and oulet.

 

[Anonymous]

Read this

http://www.advancedaquarist.com/issues/ ... turejp.htm

 

[Anonymous]

If you use a strong pump and pump the water into 4 to 6 outlets that are 1" diameter each and have each 1" pipe run down into an 1.5" elbow that is below the surface, it will difuse the flow and make it wider and weaker. Similar to how the CPR BakPaks returns are made. If you sink them deeper in the tank they will not create air bubbles and be a wide turbulent flow.

The spray bar will have concentrated flow and will not give you the flow you want.

 

[Anonymous]

Actually more like the CPR refugium return. Just more of them.

http://www.fishtanksdirect.com/aquafuge ... pping.aspx