closed loop pump sizing?

[cheezischrist]

hi, i am planning on installing a closed loop on my next build, but am a little confused . i plan on using a 1" drain and return. the return will be dead center in the back of the tank, and will be spit by a t with 45's on the ends, unglued for aiming purposes. the drain will be centered widthwise, and and centered between the bottom trim and the return. the pump will be an external pump, and will be under the tank, about 32 inches down. im just confused on what size , and kind of pump i need to get. any recomendations? thank you

 

[uncleof6]

There will be no static lift, so how far the pump is under the tank, will not make any difference. All you need to deal with is friction loss.

Max for a pump fed plumbing system using 1" pipe, would be 1200 gph, other wise the friction loss becomes excessive. Depending on which rule of thumb you wish to use, that could serve a 60, 40, 30, or 20 gallon tank. So what pump to use becomes a question of flow rate and pipe size--and since closed loops are not an efficient means of creating circulation in a tank, it is going to be a rather large pump, to eliminate dead spots. However without a flow rate, there is not an answer.

 

[cheezischrist]

thanx uncle.....i bet youll be answering a question i just asked on the silent failsafe overflow thread lol....i was planning on using hydor flows on the ends of the 45s on this return, just to alternate the water paterns. or would splitting the return using a scwd plumbed to two return holes instead maybe be a wiser choice.

 

[uncleof6]

Well those things just create more friction loss, making for the need for an even larger pump.

Probably.....

 

[cheezischrist]

ha thanks uncle, im just gonna stick with the one hole then. its really only to generate random currents, so i guess im gonna go with a 900 or 950 gph pump. so im not pushin the hydor flows to hard. i do love them in my tank now. thank you tons though, most people attack me and my ideas on here, but never really answer my questions lol

 

[uncleof6]

Honestly though, I think we get too caught up in "random" vs. "turbulent" flow. There is nothing random about water movement on the reef: it is steady, continuous, and within the top 40 or so feet, vertical circles as well, due to wave action. It is however very turbulent. Turbulence is created by steady currents colliding with each other, and with objects. The currents would be the lateral and cross-reef ocean current (global currents, which is why reefs exist at all, in the locations they are.) and the diurnal tidal currents, which are cross-reef. Surge, created by the circular water movement, are more up down.

 

[laugh]

A 900 GPH pump will destroy the hydors in no time. I ran two on a closed loop with an Iwaki 20rlxt(922GPH) The little plastic gears inside will strip out. I replaced them several times and always get the same result. My brother runs about 400GPH through two hydors and they have been going non-stop for a year now. IMO 200GPH is the most a single hydor can handle and expect it to last longer than a few months.

 

[Timber77]

I would suggest looking into a penductor for your pump return to tank, in liew of the hydor's if you put a pump around 1000gph and a have a penductor on the end you will maximize water flow and no moving parts besides the pump to break, clog up , etc.

 

[uncleof6]

I would suggest looking into a penductor for your pump return to tank, in liew of the hydor's if you put a pump around 1000gph and a have a penductor on the end you will maximize water flow and no moving parts besides the pump to break, clog up , etc.

Perhaps, but penductors are just a gimmick. Sure they have a function, however, in the fine print, you need a pressure rated pump to run them. Pressure rated pumps are anything but efficient,

The bottom line is a closed loop, whether you use hydors, eductors, penductors, orchestra conductors, whatever, is not going to do the job as well or efficiently as power heads.

 

[Cbechdel]

Excuse my lack of knowledge, but what exactly does "closed loop" mean?

I'd take it to mean something like a canister filter where if the water pumps fail, they cant overflow anything from the siphon efect since the open and closed ends of the canister input and outputs and up in the tank, so only leak could be from bad seals on canister lid.

Wheres a sump system, the water could all down and overflow.

Is this the correct understanding?

 

[uncleof6]

Excuse my lack of knowledge, but what exactly does "closed loop" mean?

I'd take it to mean something like a canister filter where if the water pumps fail, they cant overflow anything from the siphon efect since the open and closed ends of the canister input and outputs and up in the tank, so only leak could be from bad seals on canister lid.

Wheres a sump system, the water could all down and overflow.

Is this the correct understanding?

A closed loop means that the pumps moves water, in a "sealed system." A system in which water is taken from, and returned to, the same body of water, without leaving the pipe. Using like terminology, an "open loop" would be water is taken out of a body of water, moved to another body of water, leaving the pipe, and then being moved back to the original body of water. Hummmm, I think I like your explanation better...

 

[laugh]

The bottom line is a closed loop, whether you use hydors, eductors, penductors, orchestra conductors, whatever, is not going to do the job as well or efficiently as power heads.

No, but it can look way better. It's a matter of give and take. Powerheads are just ugly and I want as few pieces of equipment in my tank as possible.
Having said that I'm in the middle of a tank upgrade and I will be ditching the closed loop and using powerheads for the reasons uncleof6 stated. I'm just going to have to hide them as best I can.

 

[kcress]

Yeah, but how do you 'hide' the annoying buzz. hum, and rattle that comes with them?

 

[laugh]

I have found that any external pump capable of producing equivalent flow is far louder than any powerhead. Like I said, it's all give and take. They all have their drawbacks.

 

[Reefneophyte007]

I am in the planning process of a new setup. This will be a Peninsula style setup, tank ~ 300gallons 72" x 36" x 30". I am trying to determine best way of getting the circulation I will need in the tank to maintain sps corals happy. My previous tanks did not have closed loops and after reading the previous threads I'm not sure it is the best idea. How do I efficiently achieve the flow I will need without a closed loop? A few MP40s,60s? How should they be placed/positioned? Like most setting up a new tank, I want to try and do it right the first time. If it means drilling holes in the bottom of my tank, so be it.