correct flow through recirculating skimmer?

[prodman]

How much flow is best to run through my skimmer? I have a rc500 euro reef. And a 120g tank. I have read that 1-1.5x tank vol per hour. How importiant is that? I mean is it really dependent on the size of my tank? Or is it more dependent on the size tank the skimmer was made for? It seems my euro reef which is rated for a 500+ gallon tank should be able to function well on 500-750gph. Could I safely run 200-400 gph throught the skimmer without affecting its performance? Thanks

[prodman]

anyone?

[prodman]

^^^^

[RichConley]

I would think that as long as your skimmer is decent, it shouldnt matter too mcuh as long as you dont go to a rediculous extreme.


I kind of see this as the same as the heat exchanger thing. Speed doesnt matter.

In this case, the amount of crap in the water is what matters, not how fast you're feeding it into your skimmer.

JMO.

[Aquaticman74]

FWIW, I have a 851 Deltec on my 125. I'm supposed to be running 350 gph through it, but I'm currently pushing about 200 gph through it. The performance of what the skimmer was doing improved over when I was pushing the recommended flow through it. I think the 1-1.5x flow rate through the skimmer is correct off my improvment of skimming lowering the flow through it.

[BeanAnimal]

Rich.. you lost me.

A heat exchanger works better with a faster flow. The larger the Delta T, the more efficient the exchange...

Escobal and others have done some work with regards to skimming and turnover. In a nutshell the slower the feed rate, the better the performance. However if the feed rate is to slowthe skimmer can not keep up with the nutrient load of the tank.

In other words, slower feeds crreate cleaner output by removing the stubborn protiens but may not processes enough water fast enough to have a benefit on the tank more than a quicker feed rate that may leave the stubborn protiens.

So to answer the OPs question... slower is better. If the skimmer is oversized for the tank, then slower will not hurt, esp if it is a recirc skimmer. You'll be skimming a LOT of water even at a slow feed rate.

[prodman]

Thanks everyone. So would 500gph be considerd slow on a 12" skimmer rated for a 500g tank? What I am really after is a much flow as can get away with. I plan on feeding it via the drain line so the more flow that I use means more flow in tank which I would like.

[51504reef]

Hey paul-
In regards to heat exchangers it is my experience that too fast of flow yields a false temp reading. For example an engine that is cooled by circulating water through a radiator and back into the engine, a rapid circulation will never allow the coolant time to absorb the heat which is within the block. Thus the coolant will not extract that heat which it's meant to do. It would be comparible to touching something hot and pulling your hand away before your burned-if you keep it there longer it will let you know just how hot it is.
In relationship to a skimmer-contact time is what determines how effecient the skimmer will be. I originally installed a skimmer that was rated for 4 times my tank volume and it worked OK. I converted it to a recirc. style skimmer and used a feed pump which was 1-1.5 times tank volume and was shocked how much better the results were. I then decided to add a feed pump that was 3-3.5 times tank volume and was disappointed with the results, I concluded that the 1.5 turnover was optimal for my setup.
This is just my experience and hopefully it will work likewise for you. Goodluck

[BeanAnimal]

51504... that could not be further from the truth. Of course the "speed" of the coolant through the exchanger must be reasonable, but simple physics dictates that the higher the temperature differential between two bodies, the faster the heat will flow from one to the other. When you water pump begins to wear, the water moves slower. The water leaving the engine is almost as hot as the engine itself and the radiator can not keep up. The efficiency of the system is lost and the car begins to overheat. The idea is to send cool water through the engine and bring warm water OUT of the engine, maintaining a LARGE temperature differential between the coolant and the block.

Your "hand on something hot" example has NOTHING to do with this.

The point was that a skimmer and a heat exchanger have nothing on common.

Your conclusions with regards to skimmer flow rate or on track. The slower the water moves throug hte skimmer, the cleaner it will become. Again this is within reason, and the recirc setup helps by forcing the water to stay even longer.

Bean

[51504reef]

I'm sure you are never wrong in your observations and I am by no means an "expert" but I do know that flow rates are relevant to heat extraction. I agree that the radiator example might have been inaccurate but I was thinking of an issue with my boat where cold lake water was being forced through my engine and never having time to absorb enough heat. When the water was slowed down it had adequate "contact time" and thus did what it was meant to do. The contact issue is "relavant" and I didn't post to discredit you or argue about who's right or wrong. I was trying to help someone understand in "simple" terms why something might be improved. If it helps-your right Im wrong

[BeanAnimal]

My comments were not "observations", but rather the application of well known thermodynamics. The boat issue is a bit different in itself because the system is not a closed loop, you have an endless supply of cold water

With regards to "contact time" it is very relavant with the skimmer and a radiator... however the point was that the two have nothing in common with regards to what that contact time means or does... thats all.

As I stated I agreed with your conclusions about the skimmer contact time being of benefit (and your personal observations go a long way to adding merit to your conclusion).

I also am trying to help... the heat exchanger issue comes up quite often, and because it is somewhat counter intuitive, people get it wrong. SO... the goal was to just get good information out. Thanks for taking the time to contribute

[51504reef]

Bean.-
Sorry if I came across like I was biting your head off. I just understand and retain things when they are explained in a simpler, less scientific way that is easier to relate to. I was looking to explain that the skimmer processes more effeciently when its not rushed-guess it's like anything in life (it yields better results when its not rushed).

[BeanAnimal]

no worries... it takes a lot more than that to bother me.

[cherubfish pair]

Can recirculating skimmers be plumbed to a sump externally?

[outy]

if your using your drain line you want to put a T in so you can regulate the flow through the skimmer its very important to keep the water level stable, the extra water will just dump into your sump.

in overclocking computers we have dailed the flow thing down to a science and better flow does equal better cooling then its gets to a point that with too much flow that the extra flow does not justify itself in gains.

its the opposite here with skimming the flow set at 1-1.5 gives the water long enough to be cleaned well and theres enough flow to keep up with the tanks build up of nutrients [Balanced]

prodman 200 would be fine and a little extra wont hurt getting on the 400 side of things wont be too negative but its better to give the water the skimmer time it needs to get stubborn stuff out

[prodman]

Originally posted by the cattleman
Can recirculating skimmers be plumbed to a sump externally?

yes they can

[cherubfish pair]

Originally posted by outy
in overclocking computers we have dailed the flow thing down to a science and better flow does equal better cooling then its gets to a point that with too much flow that the extra flow does not justify itself in gains.

say what?

[outy]

water cooled computers, i have a radiator, pump and 3 waterblocks in mine lol 3.2p4 @ 4g

i ment dialed in