End to end flow

[guba807]

Due to my future job I am forced to breakdown/give up my current tank. But taking what I have learned from this, I have an idea for a new tank. But before I invest too much time in thought to this, I want some other opinions.

My idea is similar to a river tank as commonly used in freshwater loach tanks. Only instead of an under-substrate manifold, a chamber with a diffuser plate on either end of the tank. within the chamber, water could be sucked or dumped in via a closed loop pump depending on which way you want the tank to flow. The plate would be to reduce turbulance from shooting the water in the chamber and also to reduce the chance anything living getting sucked into the closed loop. I figure this would need a huge pump for the size tank I want, but I might try it in scale on a 20 long to get a good feel for pump size.

Does this flow sound feasible? Any idea what GPH I might need based on the cross-section of a tank? Would corals be adversely affected? If all this is possible, could it be valved to reverse the flow? (preferably 4 times a day to simulate tidal flow)

I probably did not explain this very well, but I will be around to help explain anything. Also, if you have seen this before, please point me in that direction.

Thanks

[zeusfc]

all very feasible... If you set up TWO closed loops (one going either way) with two pumps, and two timers, then It's simply a case of adjusting the timers, so that when one is pumping, the other is off. It would be a far cheaper option than valving it!

[guba807]

I hadn't thought about using 2 pumps as I figured the cost was prohibitive, but I guess the amount of electronically controlled valves this would need is gonna make that route expensive also. Would the daily start-sit-start-sit affect the pumps? What if they were cycled every 4 hours instead of every 6 hours? (ON for 4 hours, OFF for 4 hours)

Also, to get the flow like corals would need, can someone hint at what type of flow would be needed? For instance, if the tank is cross section is 3 x 2, and I flow 2000 GPH down the 6 foot length, will this be enough for the corals or do I need to look at increasing the flow?

My current thought is for around 5000 GPH across the tank since the plan is for a 3' x 2' x 6' (8 if I can afford/ have space)

[Pbrown3701]

With that size pump, I would look into the valve option.

[RichConley]

<a href=showthread.php?s=&postid=9660388#post9660388 target=_blank>Originally posted</a> by Pbrown3701
With that size pump, I would look into the valve option.

An electronic valve will cost you a whole lot more than a 5000gph pump.

[guba807]

I've looked into this quite a bit more. The valves are ridiculously expensive, over $250/each, so I might consider 2 pumps.
Are these (http://www.reefland.com/rho/2006/03/water_movement_reef_aquarium.php) good measurements of water flow on a reef? What about w/in the aquarium?

Also, assuming your looking at a cross section of the depth x height of your tank, what percentage of that do you think is obscured by the rocks? 25%, 40%?
I mean, if you have a 48x18x20, your cross section is 18x20, how much of that would be blocked by rocks if you were travelling down the length of the tank?

I know this method will have dead spots, but by changing direction and careful rock placement, I hope to keep those to a minimum. Will that linear flow adversely effect livestock?

[JCTewks]

i was thinking abpuit your post the other day and came up with:....maybe look at doing the end to end flow, plus a CL on an OM that would create some really cool turbulence in the tank...much like a wave coming in on the reef. I think that would really offset the strong linear flow possible problem. I don't think that kind of flow would hurt anything in you tank at all...it's just not very natural. or, i don't know if it is possible to put an OM 2 way on the input and output of your pump to switch them at the same time...that would seem more natural, maybe do the other CL as well. I Really like the idea...if i ever do an in wall i'll be seriously considering this :)

[RichConley]

Whats wrong with linear flow?

[JCTewks]

nothing really...just depends on what corals you are keeping. a lot of the corals we keep on our tanks come from areas on the reef with lots of strong random flow from waves crasing near them. most of us are actually using linear flow as a primary means of circulation in our tanks. I just think with this set up it would be very easy to take that strong linear flow and turn it into chaos with the addition of another CL or some tunze like pumps on timers.

I personally really like gubas idea...just throwing out some options...

[scottras]

I was looking to do something like this for a small tank I was planning. The idea was scrapped eventually because of financial reasons. The plan is a good one. I was originally going for a 4x1x1' tank which would be pretty easy to do.

Linear flow is a fine way to circulate water. You can use rocks to create areas of strong and weaker flow in the tank.

[Horace]

Here is how you get that kind of flow w/out using massive pumps or complicated valves. Good luck :P

http://www.advancedaquarist.com/2007/1/aafeature

[Inflames]

great article, thanks for the link.

[guba807]

Thanks for all the responses so far. I've been reading through the sources from the article posted by Horace. In particular references to this one, Riddle, D., 1996. Water motion in the reef aquarium, Part 1. Aquarium Frontiers. I've thought about the in tank setup for the gyre as shown in the article, however I'd like to see if this is possible w/o sacrificing in tank space.

JCTewks, I like the idea of a secondary closed loop to help create the random flow.

With that said, the article got me thinking about mass and momentum. If you get a column of water, say 12" x 12" moving, and you keep applying enough force to maintain that momentum. Would you be able to use a smaller volume pump than would be used to push a 12" x 12" column of water in the traditional way we do?
Right now when we move water in the tank, we push it where we want to go. So say you have an acropora colony. If we push water into it, we will have stagnant water on the backside, even though we are flowing 30cm/sec on the front. But if you pull water from the backside as well as push from the front, what type flow would you get through the coral then, and could you use a smaller pump than what would normally be used for a closed loop to do it?

I'm actually looking forward to getting the current tank broken down now so I can do some flow tests with my pumps.

[scottras]

My original plan was to use larger diameter plumbing than necesary and plumb the pump in as a bypass using 2 wye's. I hoped to get a larger flow through the tank this way. Nit sure if it would work, but thats what I was planning. FWIW I am currently trying to do a similar thing with my 2.5Gal pico.

[guba807]

Let me know how that pico works? In particular how much flow you had to use, if you use a difuser to spread the flow out from the pipe? Maybe some pictures when you have them.

I will probably start experimenting on flow requirements this summer once things settle down.