what is a closed loop?

[jill]

I'm sure some of you are rolling your eyes but I am pretty new to this. Does it mean that you just have one return pump?

 

[Saltyfish]

a Closed Loop is when you have a suction pipe from your tank to your pump and back into the top of your tank. Normally used for water movement only.

No sump or other equipment between your suction pipe to your pump and your pump to your tank. Once it is back toyour tank you kmight put sea swirls or other water movement devices. In most cases a closed loop is there to replace power heads and return through the top of the tank. Of course some plumb the pipe through the sides or bottom of their tanks.

 

[returnofsid]

Exactly. Another way of looking at it is:

Water leaves the display tank, and returns to the display tank, while never being "open" to air or other water. It's always contained in a closed circuit of pipe and pump.

When the display drains into your sump/fuge, and is pumped back into the display tank, this is an "open loop."

 

[Scooterman]

Closed Loops offer some great benefits, ie, high water movement, low power consumption cleaner interior look. In reality, larger tanks should have these along with some sort of internal devices as Tunze & others high end units similar. The tricky part is getting that random flow as you would have on the reef.

Just a follow up on the above answers.

 

[darklcd]

Scooter is right about flow but one of the better ways that I have seen "random flow" was with small internal pumps and a controller its more expensive but that is the best way that I have seen it done.

The guys here might tell you different and if I am wrong please tell me a better way lol but with a normal closed loop system there is suction into the pump and 2 or 3 outlets back into the tank but they are usually stationary and don't move. This works ok for a fish only tank or a tank with few of any corals but if you want a reef random flow is a big plus for sure

IMO of course

 

[Scooterman]

Scooter is right about flow but one of the better ways that I have seen "random flow" was with small internal pumps and a controller its more expensive but that is the best way that I have seen it done.

The guys here might tell you different and if I am wrong please tell me a better way lol but with a normal closed loop system there is suction into the pump and 2 or 3 outlets back into the tank but they are usually stationary and don't move. This works ok for a fish only tank or a tank with few of any corals but if you want a reef random flow is a big plus for sure

IMO of course

That would be the purpose of the sea swirls on the outlets & internal PH's as mentioned, that is why I'd suggested a combination.
Now that doesn't mean you can have a CL with only static water movement, you can with devices like a MBV, oceans motion etc. & these pumps will generally push very large volumes of water, all at a cost for sure but has great performance behind them.

 

[jill]

Thanks guys, this helps.

So am I understanding that you can have either an open or closed loop, not both?

How do you skim with a closed loop? I can't see how you could have a refugium - am I missing something?

 

[roscoe]

A closed loop has nothing to do with your sump , fuge and any other thing you have hooked up to the DT. It is a a closed sytem where water is drawn from the DT via a pump of your choice (preferbally external) and is returned back from the pump into the DT through how many ever ports you choose to have. I hope that makes sence to you. You can also hook your closed loop system to a MBV, OM ect. ect. to get randomized flow but that takes more equipment, plumbing and oh yeah can't forget the almighty casholla.

 

[NaH2O]

See if this thread helps you visualize a closed loop a little better.

Some Plumbing for Nikki

Here is a picture from my tank. The monstrosity in the middle goes to a separate pump (out of the sump). The water is drawn in from the tank then goes right back to the tank. Think of it how a hot tub/jacuzzi works

 

[FreakinReefin]

Thanks guys, this helps.

So am I understanding that you can have either an open or closed loop, not both?

How do you skim with a closed loop? I can't see how you could have a refugium - am I missing something?

Actually you can easily have a closed loop and an open loop in the same tank. Usually you have the drain and the return for the closed loop within the confines of the main area of the tank. The open loop would be a standard function overflow and such with a return line usually going from the top-down into the tank from the sump/refugium. Basically think of a standard reef-ready tank with an over-flow and return lines...then add three holes in the bottom of the display area of the tank, one for the drain and two returns. Does that make sense?

 

[jill]

I totally get it now.
Thanks to everyone for taking the time to explain it.

 

[alki]

I totally get it now.
Thanks to everyone for taking the time to explain it.

Ditto. I never fully understood it either.