How does it work? Vol 3: Closed loop

[Matt L.]

"Yes, yes... Its all a rich tapestry..."

Oxygenation has nothing to do with a closed loop.
That is what your overflow and skimmer do. It is about moving water.

Yes and no.

Moving water causes aeration.

So while one may say that the primary purpose of a closed loop is to move water for your corals, the movement incidentally results in aeration which also may be required.

Matt

P.S.: Can you guess which Simpsons Episode the subject line is from?

 

[Matt L.]

That would be the picture directly from his article in advanced aquarist's.

Too bad what Calfo's got there ain't a closed loop, even by the reefing definition. What he shows is just a clever return.

As I said before in this thread, and giving Calfo the benefit of the doubt, I wonder if when he says "loop", he is really referring to the ring shaped manifold (which, by the way, is hydraulically superflous), and not a hydraulic loop.

I am wondering if, with so much misinformation going around out there, and (non-hydraulic) experts such as Calfo unintentionally adding to the confusion, the BRS should have a talk on hydraulics? I would be more than happy to contribute and set the matter straight,

Matt

 

[dedfish]

Here is a link to the article
http://www.advancedaquarist.com/issues/sept2003/short.htm

He does use the term closed loop but I don't think he means it in the same sense as we are talking here.

 

[jango]

Oh, well, thank you doctor. You've changed my life!

As I said before in this thread, and giving Calfo the benefit of the doubt, I wonder if when he says "loop", he is really referring to the ring shaped manifold

Matt as you can see from my title I have an issue with a small OCD.. ..

I think that is what he is referring to...

 

[jango]

the movement incidentally results in aeration which also may be required.

How would it aerate? Why may it be required?

 

[Matt L.]

Better Late than Never

The appearance of a new, Moe-How-Does-it-Work? thread reminded me I never answered this question in the previous Moe-How-Does-it-Work? thread.

The best way to think about aeration is as something that happens passively and is goverend by the laws of chemical equilibrium. In laymans terms, its a force of nature and its going to happen whether you want it or not. The only question is: what can you do it help it or hinder it?

The gasses in the air will always try to be in equilibrium with the gasses in the water. These gasses include oxygen. While air is a whopping 21% by volume oxygen, one litre of saltwater water can only hold about 6mg.

Now lets say you have two, 5gal HD orange buckets of saltwater, one where you've sucked out all the dissolved oxygen (so you have 0 mg/L dissolved oxygen), and one where you've forced more dissolved oxygen into it than it can theoretically hold, say to 10mg/L.

Chemical equilibrium says that water can only hold 6mg/L, so over time, if you set these buckets out, the 0mg/L bucket will suck oxygen from the air in to reach 10mg/L, and the 10mg/L bucket will offgas oxygen to reach 6mg/L.

Aeration tends to be a slow process, and so for aquariums, where fish are constantly breathing the dissolved oxygen in the water, we as the aquarist need to speed it up. The rate of aeration is related to the surface area exposed to the air, so bubbling can help by injecting small volumes of air with a large surface area. Moreover, powerheads causing surface agitation turn the water in the tank over repeatedly so that not just the top layer becomes aerated.

Before there were ever SPS, people used powerheads to turn the tank water over for aeration. It turns out, bubbling isn't even necessary,

Matt

However, if you set your saltwater out in a container ont he counter

 

[snowmaker]

Great thread... I'm not sure if too late to add to but I have a few pics of an idea I had for a "above the rim" CL on my 40g breeder sps set-up. My return is plumbed to 3/4" tees and reduced to 1/2" at tee and each tee fitted with a Hydor Flo device. Works great for random turbulent flow. Currently running 5 Flo devices, that just poke through the surface, on a Q.O. 3000 pump.

 

[Cherokee_Dude]

Just wanted to bump this thread since I'm thinking through the design of my new closed loop and return plumbing design. This thread was incredibly helpful and deserved another Kudos for discussion and helpfulness.