Return Line Design

[Dom]

You could always use 2 smaller pumps instead if splitting the lines. A lot of people use pvc on the drains and soft tubing on the returns to dampen noise as well. So if you had 2 of your dc pumps running with a dedicated line to each return, you wouldn't have a problem. And that way if a pump conks out, you still have the other one running.

I know I mentioned that I dig symmetry... and redundancy too!

 

[mcarroll]

And in my next build, I plan on having multiple returns because

1. I want to eliminate the clutter of power heads.
2. I will reduces the potential of stray voltage in the tank as my power heads are AC.
3. No power heads = less money; no purchase of the heads and less electricity.

Generally those three things will not be too likely to pan out. (Sorry to be a wet blanket.)

Money and Electricity
Powerheads are orders of magnitude more efficient than what they replaced – which is why powerheads became popular in the first place. (It certainly wasn't their astronomical cost...powerhead prices are much lower these days!) What you're proposing to build is what powerheads replaced. Physics hasn't changed, so I'm afraid it will have the same associated issues.

Unless you already have the equipment so the costs are already sunk, the equipment will cost you at least as much as powerheads – probably more. It will definitely take more power. (Shoving water through a pipe using an impeller is never going to be as efficient as spinning a propeller freely in a tank of water.)

Potential For Stray Voltage
I'm sure the potential of stray voltage is a worthy concern (and something you can plan for), however, every reef in the world since the beginning of time has had AC gear in it so you know the probability of it happening is LOW LOW LOW or it would be one of the most common tank problems up there with algae.

Plus, you can't stop some gear from randomly failing, so anecdotes of stray voltage are just that. Heaters are the most likely/common source of stray voltage in my experience anyway...it seems related to equipment abuse as far as I can tell. Folks lift their pumps by the wires all the time. And folks let heaters run dry and carry then my the wires too. That's equipment abuse, and avoiding those kinds of things is an easy way to avoid some equipment failures. (I've only seen stray voltage problems on tanks where I took over from other people...never on my own....this kinda makes me think there's a little credence to the idea. I know I'm not that lucky, so that's not the explanation.)

Clutter
I've also never seen an unobtrusive closed loop system, for all the claims you read about how intrusive powerheads are.

You also can't hide the nozzles like you can hide better powerheads.

Further, you can't change a closed-loop type of flow system when your tank changes or as corals grow in....that kind of system is limited.

 

[roberthu526]

And in my next build, I plan on having multiple returns because

1. I want to eliminate the clutter of power heads.
2. I will reduces the potential of stray voltage in the tank as my power heads are AC.
3. No power heads = less money; no purchase of the heads and less electricity.

Thank you for sharing your idea. You may need a large amount of return nozzles to accomplish the no powerhead goal.

 

[roberthu526]

Yeah... I'm the same way... I dig symmetry. Thought that was only me.

Haha! Thank you for the support!

 

[Dom]

Further, you can't change a closed-loop type of flow system when your tank changes or as corals grow in....that kind of system is limited.

Good point.

 

[LobsterOfJustice]

You are thinking about the valves incorrectly. You are not restricting the flow or creating back pressure in this setup since there are two outlets. You are simply diverting water from one outlet to the other by creating more resistance on the outlet which naturally has less due to plumbing configuration. Put a valve on the line closer to the pump and call it a day. You won’t lose any flow, create any more heat, or harm the pump.

 

[mcarroll]

A valve does increase the head pressure or the flow through the system wouldn't change.

Water exerts pressure that is applied to it equally and in all directions.

So in effect you're pressing in on the one outlet a little with the valve and in response the water pushes out a little on the second channel to defeat some of the friction that was preventing more flow in the first place.

You can play with the Liquid Friction Pressure Loss calculator to see what the effect might be like by setting it up with your config and then adding a reducer and changing the reducer outlet size to various settings.

The magnitude of the effect of the added pressure on flow would depend on the pre-existing flow rate and plumbing that was already in place....and the amount of restriction that needs to be applied to balance the flow. I suspect in this case the effect on overall flow would be pretty small, but I'd check it with a calculator if I was going to be making work for myself.

 

[roberthu526]

A valve does increase the head pressure or the flow through the system wouldn't change.

Water exerts pressure that is applied to it equally and in all directions.

So in effect you're pressing in on the one outlet a little with the valve and in response the water pushes out a little on the second channel to defeat some of the friction that was preventing more flow in the first place.

You can play with the Liquid Friction Pressure Loss calculator to see what the effect might be like by setting it up with your config and then adding a reducer and changing the reducer outlet size to various settings.

The magnitude of the effect of the added pressure on flow would depend on the pre-existing flow rate and plumbing that was already in place....and the amount of restriction that needs to be applied to balance the flow. I suspect in this case the effect on overall flow would be pretty small, but I'd check it with a calculator if I was going to be making work for myself.

This is awesome! Thank you for the tips and advices! This hobby is really about learning!

 

[LobsterOfJustice]

Of course there will be some additional resistance, because you are forcing water to go down the path that it didn’t originally want to go. But even if you crank the valve down to completely closed, you’ve just created a typical system with a single return path. My point is this isn’t hard on the pump and won’t add heat to the tank. You can accomplish the same line balancing by adding a bunch of elbows or extra piping to the shorter side, but a valve does the same thing easier and cheaper.

 

[Keepingitunreal]

Smart stuff