jmaneyapanda wrote: please do not make the claim that the larger skimmers are not better at skimming smaller tanks- this is untrue. This is the only point I am arguing.
I don't believe that was an issue for debate at least for me. I simply stated that overskimming is impossible (I think we all agreed on that with some specific exclusions), that and I am quoting myself "You want to find a skimmer that is sized appropriately to your system or one that is very easy to adjust." as some large skimmers don't have gate vavles or can be difficult to setup in a small sump, and to quote again "The focus should be on the design of the water flow, pulling water into the skimmer from the correct place and making sure you don't have a skimmer too small." which again I think we can agree on.
Your original dispute with a statement I made later was quoting me (yet again)... "It isn't that you can't get a good skim out of a skimmer too large for the system, it just takes more adjustment (generally speaking). That said there are some skimmers that are huge and have excellent adjustment capability that could work on even the smallest systems."
At no point did I say you wouldn't get as good a skim from a larger skimmer. I think you would.
The point we seem to disagree fundamentally on is that there is some point where an oversized skimmer is skimming as well as a hugely oversized skimmer. I don't think short of a live test either of us will budge on that one.
The other and I am not sure how we disagreed was from my statement that some large skimmers are built for a certain bio-load and flow and are more difficult to adjust with smaller bioloads and possibly smaller flows (those without a gate valve... such as the larger ASM skimmers come to mind), but there are some large skimmers that are easy to adjust and aside from heat and price will work just fine. I am not sure how we disagreed, but I think it was in there somewhere.
jmaneyapanda wrote: But as per your example, the larger skimmer should be able to pull out more organics. Perhaps it will be a small bit more, or even negligible to the naked eye, but if it is capable of skimming faster and larger scale, it will skim better.
This would require a live to test for either of us to be satisfied I believe. I just don't think there is that many organics produced by two fish in a 20 gallon tank for either skimmer to miss much. Again, this is a fundamental difference of opinion and I don't think either of us is going to budge without some provable numbers.
jmaneyapanda wrote: Unless you want to make the claim that the smaller skimmer is pulling out 100% of the organics (which I assume you are not claiming).
I believe the fish and other parts of the tank are constantly excreeting waste and such so that a skimmer will never be done doing its job. However, I do believe that the smaller Tunze will pull out 99% of the waste in roughly the same time the larger Tunze will pull 99% of the waste out on a tank that small. They are both so massive and the turnover so complete that they are going to pull whatever could be reasonably pulled out quickly. There probably is some difference, I would just argue that it isn't noticeable on any level from the health of the fish to the measurements of the water itself. I believe in a blind study, the amount of skim and water quality will be nearly identical between the smaller skimmer (which is still oversized for the tank) and the massively oversize skimmer.
jmaneyapanda wrote: But does the performance of the larger get better as the tank volume grows- no. It will if anything, pull out less of the organics as the tank grows, not more (because it is not getting as thorough a turnover as when it was smaller).
I believe this is wrong in a certain aspect. If a skimmer is pulling 2 cups of skim a day and you increase bio-load in the tank, it isn't going to pull out less than 2 cups the next day. It might pull out the same because the skimmer is at capacity, but it won't pull out less. If you increase the water capacity of the tank and thus reduce flow, then yes you are probably going to get less skimmate. However if you increase a 20 gallon to a 25 gallon, bio-load remained exactly the same and you were getting a cup a week, you probably will still get a cup a week mainly because your supersized skimmer is still turning the water over a rediculous amount.
jmaneyapanda wrote: Lets look at it another way. Hang on power filters- One with 100 GPH and ones 400 GPH (same manufacturer, just larger "sized" models). Which one will work better on a equal tank? The larger, right? It is the same principle.
If it is a very small bio-load and the skimmers are both high quality, they will both work equally well when it comes to maintaining water quality. I also believe the skimmate will be nearly identical. Again, a fish can only crap so much. I know a skimmer can't get everything and fish continually crap but the speed at which it reaches maximum water quality can be obtained if both skimmers are sized significantly larger than what they are skimming even if one is much bigger than the other in roughly the same time (design elements being equal).
I need to copy this onto reef central and let some of those bio-chemist take a whack at this and see what they say.