Pies Posted August 21, 2006 Report Share Posted August 21, 2006 No, i'm not a scientist, i'm an engineer, (engineering = applied science) and i've studied and anyalysed these type of systems (plus a lot more advanced ones) for the last 4 years. Hahahahahahahaha. Quote Link to comment Share on other sites More sharing options...
Fay Posted August 21, 2006 Report Share Posted August 21, 2006 Pies wrote: Quote: I want a place where things can survive away from the predation in my display So do I So should I take that huge bristle star out? BUMP Quote Link to comment Share on other sites More sharing options...
suphew Posted August 21, 2006 Report Share Posted August 21, 2006 Pies wrote: Quote: So do I So should I take that huge bristle star out? BUMP Depends what you want to keep alive in your sump, bristle stars will eat anything larger they can catch, snails, sick fish, etc, but don't think it would make a dent in your pod etc population, they are just too small and fast moving. Quote Link to comment Share on other sites More sharing options...
suphew Posted August 21, 2006 Report Share Posted August 21, 2006 He's wrong. Look at the spreadsheet and follow it logically you'll see why. As an "applied scientist" you should know that making up a graph yourself to support your own thoery and then trying to use it as proof is a waste of time, I could draw a graph to showing the world is flat but it doesn't make it true. Quote Link to comment Share on other sites More sharing options...
wasp Posted August 22, 2006 Report Share Posted August 22, 2006 Pies wrote: So do I So should I take that huge bristle star out? Unless there is something in your fuge the bristlestar will attack, it should be fine in there. It is not going to bother pods & the like. If you give him the odd bit of mussel or whitebait he'll do fine. No point giving him too much though my old one had an insatiable appetite I could not fill him, or I guess I could have if I wanted to pollute the tank. He just expanded the top of his head like a balloon to fit more food in. Quote Link to comment Share on other sites More sharing options...
Feelers Posted August 22, 2006 Report Share Posted August 22, 2006 If I'm your average reefer on here, and I have a 500L tank and add a refugium, the difference in buildup of waste is probably not even noticable. Just because the skimmer has a lower efficiency, it doesnt appear anecdotally to make any difference. There are far more factors involved that you cant easily work out. Is the relationship between skimming and concentration inversly proportional? I doubt the equation would be a simple one. The amounts of water a refugium adds are not enough to overwhelm the skimmers that people use. Take your tank for example - if you doubled the volume do you think your nitrates/phosphates would double? I dont think any difference would register. Its the size of the difference in nutrients within the system that people are worried about, not efficiencies. Even if your tank is less efficient (because of more water), I'm not convinced that you would register a difference. The nutrients produced by the refugium might be more easily skimmed than others, taking in crud missed by the skimmer and concentrating it in nice bacterial packages, who knows. The corals seem to like the pods etc. Quote Link to comment Share on other sites More sharing options...
wasp Posted August 22, 2006 Report Share Posted August 22, 2006 As an "applied scientist" you should know that making up a graph yourself to support your own thoery and then trying to use it as proof is a waste of time, I could draw a graph to showing the world is flat but it doesn't make it true. The old scientific gobbledegook trick! :lol: I can remember something even funnier by the same guy, when asked to provide references to prove what he said, provided a quote. Upon checking, it turned out the quote was, you guessed it - from the same guy. Quote Link to comment Share on other sites More sharing options...
lduncan Posted August 23, 2006 Report Share Posted August 23, 2006 If you guys are done, i'll explain step by step, why I say that adding extra water volume does nothing in terms of reducing the concentration of nurtients. I'll do this step by step, and I'll wait for agreement for you at each step before moving on, if you don't agree say why. Starting with the skimmer, we all know that skimmers work by waste dissolved in the water bumping into bubbles, and through polar interactions getting stuck to them. Lets say that the skimmer is 100% effecient, meaning that every but of waste that comes into the skimmer hits and attaches to a bubble and is removed. NOTE: this is NOT the same as running at 100% capacity. How much waste can the skimmer pull out during an hour of running? Well if we have x litres of water going through the skimmer in an hour, and each litre of that water contains y grams of waste, and because we've said the skimmer is 100% efficient it means that the waste removed in an hour is going to be x*y grams So now you can see that the skimmer output (when it's not running at 100% capcity) is independent of the volume of waste in the system. It's only related to the flow rate of water though the skimmer, and the concentration of waste in the water (and an efficiency factor defined to be 1 here). Is this correct so far? Quote Link to comment Share on other sites More sharing options...
wasp Posted August 23, 2006 Report Share Posted August 23, 2006 Feelers last post made a lot of sense, how do you explain that, Layton? Quote Link to comment Share on other sites More sharing options...
lduncan Posted August 23, 2006 Report Share Posted August 23, 2006 don't try and divert attention, does what I posted make sense? Quote Link to comment Share on other sites More sharing options...
chimera Posted August 23, 2006 Report Share Posted August 23, 2006 *yawn* Quote Link to comment Share on other sites More sharing options...
JDM Posted August 23, 2006 Report Share Posted August 23, 2006 makes sense to me so far layton. im in for the next step. Quote Link to comment Share on other sites More sharing options...
lduncan Posted August 23, 2006 Report Share Posted August 23, 2006 Thanks for the response JDM. suphew, cracker, wasp, can I assume by your silence you agree with that post so far? Quote Link to comment Share on other sites More sharing options...
suphew Posted August 23, 2006 Report Share Posted August 23, 2006 Makes sense to me so far, althrough doesnt reflect reality since I don't believe there is any such thing as 100% efficient skimming. But for the sake of making this easier to understand I'll go with it so far. Quote Link to comment Share on other sites More sharing options...
lduncan Posted August 23, 2006 Report Share Posted August 23, 2006 That's true, there is not such thing as 100% efficiency in practical terms. But since you mentioned it, just as an aside, lets look at the efficiency factor. It will be a function of the concentration of bubbles, bubble size, waste to bubble affinity, orientation of the waste relative to the bubble surface, bombardment rate of waste to bubbles, the surface area available for attachment etc, but it's not going to include the total system volume as a parameter or the total volume of waste in the system. So the inclusion of efficiency in the argument doesn't change the statement I make previously: So now you can see that the skimmer output (when it's not running at 100% capcity) is independent of the volume of waste in the system. It's only related to the flow rate of water though the skimmer, and the concentration of waste in the water (and an efficiency factor defined to be 1 here). All it does is unnecessarily complicate the description. Which is why I lumped it all into one thing called the "efficiency factor". Right? Quote Link to comment Share on other sites More sharing options...
suphew Posted August 23, 2006 Report Share Posted August 23, 2006 but it's not going to include the total system volume as a parameter or the total volume of waste in the system. You forgot to include dwell time, which does make total system volume a major factor. Quote Link to comment Share on other sites More sharing options...
lduncan Posted August 23, 2006 Report Share Posted August 23, 2006 How is dwell time related to total system volume? Dwell time is just a function of the volume of the skimmer, and the rate of flow through it. For example, if a skimmer has a volume of 100 Litres, and you put 1,000 litres an hour through it, you get a (very oversimplified) average measure of dwell time of 6 minutes. Again the total system volume doesn't come into it, just the flow through the skimmer and the skimmer volume. Right? Quote Link to comment Share on other sites More sharing options...
suphew Posted August 23, 2006 Report Share Posted August 23, 2006 How is dwell time related to total system volume? Dwell time is just a function of the volume of the skimmer, and the rate of flow through it. For example, if a skimmer has a volume of 100 Litres, and you put 1,000 litres an hour through it, you get a (very oversimplified) average measure of dwell time of 6 minutes. Again the total system volume doesn't come into it, just the flow through the skimmer and the skimmer volume. Right? No it's not right, because there is a minimum dwell time required for each different type of protein to attach to the bubble, and a minimum or ideal turn over of the total system through the skimmer, therefore if the volume of your skimmer is too low to give you the required dwell time and turn over you wont be getting 100% effiencey. As I underdstand it this is one of the main parameters (or caculations) for determining the system volume size rating of a skimmer. Quote Link to comment Share on other sites More sharing options...
lduncan Posted August 23, 2006 Report Share Posted August 23, 2006 You're getting off track here. We're not talking about sizing skimmers for system volume, we're talking about a skimmer which has a certain fixed flow through it, and a certain fixed volume. The dwell time of water in a skimmer is NOT determined by the total system volume. It is determined by the flow through the skimmer and the skimmer volume. Layton Quote Link to comment Share on other sites More sharing options...
lduncan Posted August 23, 2006 Report Share Posted August 23, 2006 If it helps, think of it this way Tank 1: Holds 2,000 litres with an AP902 skimmer on it with a flow of 2,000 L/hr through it, and a volume of 100 L Tank 2: Holds 1,000 litres with an AP902 skimmer on it with a flow of 2,000 L/hr through it, and a volume of 100 L Which skimmer has the longer dwell time? Quote Link to comment Share on other sites More sharing options...
suphew Posted August 23, 2006 Report Share Posted August 23, 2006 Neither, but the water in tank 2 will be processed/skimmed twice as often as tank 1, therefore water in tank 2 will be twice as 'clean'. Okay an over simplifcation, but ignoring limiting factors, changes in efficiency etc, the statement is basically correct. But anyway the point is you listed a number of factors effecting the efficiency of a skimmer but not dwell time, then stated that water total system water volume wasn't a factor. Dwell time is a major factor, and therefore system volume is also. Quote Link to comment Share on other sites More sharing options...
lduncan Posted August 23, 2006 Report Share Posted August 23, 2006 Neither Exactly, so we've established that the dwell time of a skimmer is NOT related to total system volume. Just the flow through the skimmer and the skimmer volume. but the water in tank 2 will be processed/skimmed twice as often as tank 1, therefore water in tank 2 will be twice as 'clean'. Okay an over simplifcation, but ignoring limiting factors, changes in efficiency etc, the statement is basically correct. No that's wrong, the water won't be twice as clean, the concentration of waste will be the same in both. I'll show this later. I want to get this dwell time cleared up first. But anyway the point is you listed a number of factors effecting the efficiency of a skimmer but not dwell time, then stated that water total system water volume wasn't a factor. Dwell time is a major factor, and therefore system volume is also. No, dwell time has nothing to do with the total system volume, you've just agreed with that with the example above. The total system volume only comes into it when you are sizing a skimmer for a particular system to get optimum dwell time. But dwell time itself is NOT a function of the total system volume. However i'm not talking about sizing skimmers for a particular system volume, we are looking at what happens when you have a system with a skimmer, then you increase the water volume of the system, WITHOUT changing the flow through the skimmer, or the skimmer itself. Right? Layton Quote Link to comment Share on other sites More sharing options...
wasp Posted August 23, 2006 Report Share Posted August 23, 2006 Thanks for the response JDM. suphew, cracker, wasp, can I assume by your silence you agree with that post so far? No, my silence indicated I have other things than this to do sometimes :lol: I have read your posts Layton & there are a few potential holes in your argument, although that will become clearer once you move things along to wherever you want to go. However please define exactly what it is you are trying to prove? I must have lost that somewhere. Once I know that I'll be able to detirmine the value of this discussion to me, and if I need bother with any of it. Quote Link to comment Share on other sites More sharing options...
Feelers Posted August 23, 2006 Report Share Posted August 23, 2006 Layton what would happen to your nitrate levels if you doubled your system volume? Do you think there would be a measurable change? Quote Link to comment Share on other sites More sharing options...
cracker Posted August 23, 2006 Report Share Posted August 23, 2006 I agree that smaller water volumes pass through skimmers more often, therefore have a better chance of clenaing, however... The concentration of the nutrients in the water column of the larger system will be more spread out than the smaller system therefore the inhabitants of the system will only come into half as much contact as the smaller system. The skimmer in the larger system will still get skimmed just as efficiently because you have obviously added a larger skimmer. Dont forget this.... I agree with the skimmer statements Layton, but thats not what this is about. Look at it this way: Two tanks... 1: 1000 litres with 100kg LR, 20 corals and 20 fish, small skimmer. 2: 2000 litres with 100kg LR, 20 corals and 20 fish, larger skimmer. Tank 1 will have the same nutrient levels as tank 2 due to the waste load produced by the inhabitants and LR, (This a set measurement), however these nutrients are spread out throughout the larger water column and are diluted. The bigger skimmer will pull these out just as fast as the smaller tank and skimmer, as it is rated for more literage. Similar to the air at sea level in contrast to the top of Mt Everest where the air is almost zero. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.