Two or more closed loops - counterproductive?

[IANick]

So, as I continue to research my upcoming 200 plus gallon build, I'm narrowing down what it is I want to achieve (although it seems to change daily I might add). I certainly want to use closed loops (exclusively if possible) to eliminate ugly powerheads.

So with respect to the closed loops, here is what I may have have planned at present...

3 separate locline loops buried beneath my substrate, although only two will be active at any one time. Two of these loops will be alternated, one on and one off, using an actuated 3-way valve on a 6 hour and 12 minute timer. The 6 hours and 12 minutes obviosuly to simulate incoming and outgoing tides. I feel pretty comfortable with this approach so far. It will be a similar set up to what Paul Whitby did in his beautiful 600 gallon tank in that the first loop will be designed to send water around the tank like a racetrack in one direction (i.e. roughly parrallel with the bottom and top of the tank) then switch off, and the other will then go in the other direction.

But it is the next loop I am not sure about. I'm think of using a 4 way Oceans Motions to create a reverse barrel roll effect (i.e. a loop that will be creating a flow perpindicular to those described above). This one I would like to let run continuously. On the plus side it would create some chaotic interaction with the active racetrack loop but, on the down side, it may just destroy the effectiveness of both loops. Any thoughts?

Nothing is set in stone yet, so a free flow of ideas and opinions would be appreciated.

 

[IANick]

Bump

 

[Steveb]

I have absolutely no background with them but I would be concerned they would create interference messing up the gyre your tyring to create.

 

[IANick]

Thanks Steve. That was my thought/concern. Anyone out there actually tried something similar? If it helps, I'm thinking of ramping up and down the flow on the "racetrack" loops via controllable waveline dc pumps. Perhaps I could ramp up/down the flow of the Oceans Motions "barrel roll" loop in inverse proportion to the racetrack loop? In other words, when one of the racetrack loops is at full output, the barrell roll loop is at minimal output and vice versa? A typical sequence might be like this:

1) clockwise racetrack loop starts up at minimal flow and barrel roll loop is a maximal flow... I'd hope the barrel roll gyre effect could be maintained in this situation
2) clockwise racetrack loop ramps up to medium flow after 1.5 hours and barrel roll loop ramps down to medium flow (I'd assume this would achieve maximum chaotic flow)
3) clockwise racetrack loop ramps up to maximal flow at 3 hours and barrel roll loop ramps down to minimal flow... I'd hope the racetrack gyre effect could be maintained under these conditions
4) clockwise racetrack loop ramps back down to medium flow at 4.5 hours and barrell roll at medium (again, likely chaos)
5) clockwise racetrack loop finishes its 6 hour (and 12 minute) cycle back at minimal flow and barrel roll loop back to maximal flow

.... Then the whole thing reverses on the counter-clockwise loop.

Thinking about it more, IF IT WERE TO WORK, I like the blend of alternating gyres I'd create in three dimensions (horizontally clockwise, horizontally counterclockwise, and a vertical barrel roll) as well regular chaotic flow. I'm just not sure the gyres will be maintained in the maximal/minimal scenarios.

Thoughts?

 

[IANick]

Your photos didn't seem to open for me MS4. But, regarding pumps, if i follow through on this setup, I intend to use one dedicated pump (probably a waveline controllable dc pump) on the two "racetrack" loops (switching back and forth between the two loops controlled by a Hayward 3-way actuated ball valve), and a separate pump (again a waveline) on the oceans motions barrel roll loop. I'll probably use penductors on all locline returns (assuming the waveline pumps can deliver enough pressure to get a good Venturi effect on the penductors... I'm still not clear on this).

 

[Steveb]

I like the idea! But like i said I'm no expert in fluid dynamics. There are a couple of guys in my local club w/closed loops but they are using big reeflo pumps to drive them and definitely not trying to get 2 separate gyres going.

 

[ca1ore]

Seems terribly complex to me! Never used an oceans motion device, but I have use 3 way actuated ball valves with nothing but problems. I just think that the more complex your system the more you open yourself up to a rash of problems. In my current setup, I use a single CL pump attached to a length of PVC with holes in it that runs behind my live rock. Idea is to prevent buildup of detritus and avoid any kind of nutrient sink. I then use a couple of Vortech powerheads for water column circulation. Simple and effective!

 

[Timber77]

i used big closed loops in the 90s... one swirling the bottom in a circle and the top had a 4 way and all 4 of the outlets were on ocean motions "revolution" which were spinning end pieces...it was great for flow...pain in the butt as it took up alot of real estate ( even if the pipes are hidden in the display its alot of extra junk...now i just use 2 wp40s and the reef angel it works better and much cheaper.

 

[IANick]

Thanks Timber. How big was your tank?

 

[acesq]

IANick:

So what did you decide? I'm having a tough time deciding between closed loop(s) and powerheads for my new 340 build. My big concern is generating enough flow in the tank without the use of powerheads. I am considering one or two closed loops and a Tunze wavebox or hiding some powerheads behind a false wall or???

 

[FuzzyZipperbaum]

Anytime we are adding more it always adds complexity. I think the first question you have to ask yourslef is how much flow do you want from your closed loop? for example I have a 500g with a 10000l DC pump feeding 3 outlits. It provides nice flow but I would not run it without the hidden powerheads as it would not be enough. On the other hand I currently am playing with a CL on the other 500 g that has a hammerhaead attached to it.....Flow is great...Noise is higher....so is electrical consumption. Bascially if you want a flow coming from a DC pump for electrical consumption and flexibility in randowm flow...you have to go with a dc pump. If 1 dc pump does not produce enough flow....then move to 2....For me...if I wanted more, I like the idea of using one big pump and doing random flow by messing with the return line placement.... I have started a build thread which may or my not help....lunatic fringe....

 

[Dmorty217]

If you are doing a closed loop I would look into penductors on the end of your closed loop. They pull thru 8g of water for every 1g that is actually pushed thru. I have a 220g with a closed loop setup with a reeflo hammerhead and 6 penductors all pointed upward I might add to keep the sand from being blown everywhere. I have somewhere around 28-30k gph with this setup and it works beautifully. I have 2- 2" returns feeding my closed loop with a 1-1/2" coming back. I also have a mp60 in the tank but mostly just to further randomize the turbulent flow. As far as the motion oceans 4 way, I don't have any experience with them but keep in mind whatever you do be sure and design the closed loop for easy cleaning of the pump and other parts of the system

 

[IANick]

Hi acesq:

To be honest, I'm still not sure. But I'd say I'm 80% in favor of doing what I described. The tidal motions and gyres may or may not work as I hope, but I've come to the conclusion that if I have three separate loops in place and large enough pumps (waveline is making a new apex controllable 20,000 lph pump) that even if things don't work as envisioned, at the very least I'll have enough chaotic flow to eliminate powerheads. Of course I'll have a lot of piping to hide in the rockwork and below the sand, but if well planned, I think it is doable. I should probably add that I'll likely use penductors OR, better yet, a modification to locline that emulates a penductor without the added bulk (it may not be entirely as effective as an actual penductor, but the consensus seems to be that the modded locline enhances flow to some degree via a Venturi effect... There's a thread on this topic here on RC). Someone once said to me to over design the capacity of a closed loop system so you have the ability to increase flow when the day comes - and it will - that you need more flow. With multiple loops fitted with penductor emulating locline mods all powered with multiple rampable dc pumps, I think it can work.

But I'm not sure about the actuated ball valve switching. I really want to do this because it will eliminate one set of intakes for the closed loops (my main motivation) and eliminate a pump (a much lesser motivation since the automated actuators are not much cheaper than many pumps)... But I've been hearing very mixed opinions about the effectiveness of using actuators. And I've aLso heard they're noisy which is contrary to my desire for a silent setup (though it may not be a huge deal as the actuator will only be switching the flow 4 times per day).

Last note... I should add that my envisioned tank size is now closer to 300g... 72L x 34W x 32T.

 

[Timber77]

250 display tank... i did add in a few more wp40s as have sold off some other equipment. CL definatley work, but just alot of extra places for leaks, and take up real estate. the penductors are spectacular, downside is running big pressure rated pumps. I tend to go for the lower electrical bills these days. never have used a waveline pump , i have used sequence, reeflo, and iwaki pumps all work great. not sure about ramping up and down the cl pump ,as the OM it will basically do that already

 

[guserto4]

This thread proposition is much like what I have been thinking of doing in my 300, I even planned on DC pumps- however my tank is excessively shallow (13.5"). I think it is a great idea, but the issue of how to implement is a little more difficult. I think it comes down to a lot of fiddling around to get it to work as anticipated, but I think unlike me you have the water volume depth to pull it off.
Bump.

 

[IANick]

Thanks guserto4 for the encouragement. And to others who have been cautioning me about the potential for leaks and/or a host of other problems - I hear you! Believe me, I will be going into this with my eyes open. But I really do think this can work - and work well - if planned correctly.

Thoughts from others remain welcome!

 

[IANick]

I should also add that I am re-evaluating the need for a Oceans Motions given the ramping capability of the wave lines. I still intend to have the reverse barrell roll... just using the rampable pumps instead of the OM.

 

[acesq]

I should also add that I am re-evaluating the need for a Oceans Motions given the ramping capability of the wave lines. I still intend to have the reverse barrell roll... just using the rampable pumps instead of the OM.

I'm going the same direction -- two DC pumps to create a gyre, one will push water in one direction across the bottom the other in the opposite direction across the top toward the overflow. Just can't decide on the right pump...

 

[dkeller_nc]

In answer to your original question - yes, you will get both patterns of reinforcement and cancellation with the setup you describe. It's pretty much impossible to predict precisely because to get an accurate model you'd need to precisely specify the size, shape and placement of your rocks.

But in generally, adding a flow field that's perpendicular to another simply leads to an additive flow in a direction that's diagonal to the two original field fronts.

A couple of comments about your proposed setup from someone with an engineering & science background:

Loc-line introduces huge amounts of head pressure to a flowing fluid in a pipe. It does give you after-installation adjustability, but at a high cost. Depending on the diameter and length of the loc-line segment and the velocity through the pipe, you may lose as much as 1/2 of the total volumetric flowrate.

For a set-up that will be this $$$ heavy on the equipment investment side, you might consider using the FlowWolf digital flow diverter from DerKroon mechanics. They're not exactly cheap, but not horrendous either. One aspect of using drum-type flow diverters - make sure that you install them on the underside of the tank over the sump so that if the drum seal leaks (all diverter valves will leak at some point), the water goes back to the tank.

Finally - there's a good reason that most folks choose large Tunzes or Vortechs for a tank of the size you're contemplating - they are far more efficient than closed loops, and they allow ultimate flexibility for changing the flow fields after all of the rockwork and/or corals are in the tank (such as accommodating the colonies' growth and subsequent flow-shading of other colonies).

 

[Aquatron]

Some good options given above regarding DT water movement. There is a difference between the flow's given off by a close loop system and that of MP powerheads. With a well designed close loop system you can have several areas of Turbulent flow with a MP system using at least 2 you can have 1 area. That area would be only where their flow paths crossed/meet around the middle part of the DT.
MP's are a nice product and have their place just a close loop system does, but they are different in what they can do.

Great ReefN!!!